Current Issues in Archaeological Computing 9780860543442, 9781407343358

Citation preview

Current Issues in Archaeological Computing

edited by

M. A. Cooper and J .· D. Richards

BAR International Series 2,71

1985

·B.A.R.

5, Centremead, Osney Mead, Oxford OX2 0ES, England.

GENERAL EDITORS A.R Hands, B. Sc., M.A., D.Phil. D.R Walker, M.A.

BAR -s271,1985 :'Cur r ent Issues in Ar chaeological Computing'

© The Individual Authors,1985

The authors’ moral rights under the 1988 UK Copyright, Designs and Patents Act are hereby expressly asserted. All rights reserved. No part of this work may be copied, reproduced, stored, sold, distributed, scanned, saved in any form of digital format or transmitted in any form digitally, without the written permission of the Publisher. ISBN 9780860543442 paperback ISBN 9781407343358 e-book DOI https://doi.org/10.30861/9780860543442 A catalogue record for this book is available from the British Library This book is available at www.barpublishing.com

Current issues in archaeological computing The third annual conference on techniques of archaeological excavation Edited by Malcolm Cooper and Julian Richards

iii

CURRENT ISSUES IN ARCHAEOLOGICAL COMPUTING

The Third Annual Conference on Techniques of Archaeological Excavation: Machine-based and machine-assisted post-excavation techniques edited by Malcolm Cooper and Julian Richards with contributions by: Martin Carver Malcolm Cooper John Hinchliffe Jeremy Huggett Joe Jefferies Gary Lock Dominic Powlesland Paul Reilly Julian Richards John Schofield Dick Spicer Paul Tyers The Conference was held under the auspices of the University of Birmingham Department of Extra-Mural Studies, Birmingham University Field Archaeology Unit, and the Institute of Field Archaeologists.

iv

CONTENTS

Page vi

List of contributors Editorial preface: Malcolm Cooper and Julian Richards J.Schofield ·and P.Tyers

1

Towards a computerised archaeological 5 research archive.

J.Hinchliffe and J.Jefferies

Ten years of data-processing in the Central Excavation Unit.

17

D.J.Powlesland

Random access and data compression with reference to remote data collection: 1 and 1 = 1.

23

G.Lock

A new direction or a new distraction: 35 a pragmatic assessment of computer applications in archaeology based on work at Danebury hillfort.

M.O.H.Carver

The friendly user.

47

P.Reilly

Computers in field archaeology: agents of change?

63

M.A.Cooper

Computers in British archaeology: the need for a national strategy.

79

J.D.Richards

Standardising the record.

93

G.Lock and R.D.Spicer

Real and imaginary limitations of micro-computers in archaeology ..

103

J.Huggett

Expert systems in archaeology.

123

V

LIST OF CONTRIBUTORS

Martin Carver, MIFA, Birmingham University F ield University of Birmingham.

Archaeology Unit,

Malcolm Cooper, AlFA, Birmingham University Field Archaeology Unit, University of Birmingham. John Hinchliffe, MIFA, Central Excavation Unit, H istoric Buildings and Monuments Jeremy Huggett, Research Centre f or North Staffordshire Joe Jefferies, Central Excavation Historic Buildings

Commission

Unit, and Monuments

Commission

Dominic P owlesland, Heslerton Parish Project. Paul Reilly, Research C entre For North Staffordshire

Computer Archaeology, Polytechnic.

Julian Richards, AlFA, Department of Archaeology, University of L eeds. John

Schofield,

Dick Spicer, Research Centre North

MIFA

f or

Staffordshire

Paul Tyers, Department of Museum of

Urban

England.

f or

England.

Computer Archaeology, Polytechnic.

Gary Lock, MIFA, Danebury Trust.

Department of Urban Museum of London.

f or

Archaeology,

Computer

Archaeology,

P olytechnic.

Archaeology,

London.

v i

ALICE:

Would

you t ell me

p lease,

which way

I ought to

go

f rom h ere? CAT: ALICE: CAT: ( Lewis

That

d epends

a good d eal on where

I don't much Then

i t

Alice

to g et

care where...

doesn't much matter

Carroll,

you want

which way you g o.

i n Wonderland)

v ii

t o.

EDITORIAL P REFACE Malcolm Cooper

a nd

Julian Richards

This volume i s the outcome of the third A nnual Conference on T echniques o f Archaeological Excavation, h eld on t he theme of machine-based and machine-assisted post-excavation t echniques. The Conference was h eld i n Birmingham on 8 th December 1 984 under the auspices of the University o f Birmingham D epartment o f Extra-Mural Studies, B irmingham University F ield A rchaeology Unit, a nd the I nstitute o f F ield A rchaeologists. The f orm which i t took was l argely decided by Martin Carver and Malcolm Cooper, whilst Judy Lawson u ndertook the organisation. These p roceedings have b een published through the encouragement and a ssistance o f David Baker, Publications Officer o f the I nstitute o f F ield Archaeologists, a nd others. Val Wainhouse, of the Department of Archaeology, L eeds University, word-processed many o f the papers, a nd Paul Reilly and c olleagues a t the Computer C entre, North Staffordshire P olytechnic, p roduced the c amera-ready c opy. Whilst the content o f each paper i s the work o f the i ndividual authors, overall r esponsibility f or the volume must r est with the editors. I t b ecame apparent i n Birmingham that a number of a rchaeol ogists were b ecoming i nterested i n g eneral theoretical a nd methodological i ssues of why they were u sing computers, a nd not j ust w ith particular d etails o f how they were doing i t. Throughout the day a number o f questions r ecurred, s uch a s h ow a rchaeologists s hould b ecome computerised, whether this was always b eneficial, whether s tandardisation was always a good thing, a nd s o on. I t became c lear that a number of these i ssues were p ressing, a s d ecisions b eing taken a t the moment were d etermining the future course o f d evelopment of British a rchaeology. I t also b ecame apparent that such decisions were f requently b eing taken w ith l ittle p rior d iscussion. When i t was d ecided t o publish these p roceedings the i dea was t hat the questions could t hen b e g iven a w ider a iring, a nd that d iscussion could b e p romoted i n the a rchaeological f raternity, not j ust i n Britain, b ut abroad

a s well.

Not all the papers p resented a t the Conference a re published h ere, nor do the papers appear i n the order i n which they were g iven, a nd s everal other papers, which w ere i nvited by the editors i n o rder to f ill particular g aps, have

a lso b een

i ncluded.

The volume b egins with d escriptions of e stablished c omputer f acilities i n s everal o rganisations. John Schofield a nd Paul Tyers d escribe t he computers i n u se i n the a rchive o f t he Department o f Urban A rchaeology i n t he Museum o f London. They d iscuss the range o f questions t hat might b e a sked of a computerised a rchive, a nd describe t he c urrent range o f enquiries. They c onclude that at p resent, the

1

development of a rchaeological models a nd hypotheses i s l agging b ehind the availability o f the data. I t i s suggested that eventually the data a rchive may r eplace the a ctual material a s the basis f rom which future r esearchers w ill work. I f t his i s s o, then f irst t he physical problems o f s torage of computerised data, particularly the ' shelf l ife' o f magnetic media, w ill have t o b e r esolved. This i s one o f the p roblems raised by John H inchliffe a nd Joe J efferies. They d escribe the development o f computing f acilities a t the C entral Excavation Unit. The Unit was o ne of the f irst t o go ' computerised', b ut they a re now r eplacing their o riginal Research Machines 3 80Z w ith a p owerful n etwork system. Dominic P owlesland d escribes h is experience i n i ntroducing on-site c omputerised r ecording i n a rather d ifferent type of organisation, a t the H eslerton P arish Survey p roject. P owlesland a rgues t hat the gains i n efficiency f rom u sing a d irect entry s ystem outweigh t he c osts of d evelopment. Some f orm o f data coding i s s een a s an e ssential f eature o f this k ind of system, a nd P owlesland g ives a f ull d escripti on o f the t echniques o f data compression i n u se a t West H eslerton. Gary Lock d iscusses s everal methodological i mplications o f the application of computers i n a rchaeology, i n the l ight o f h is experience a s computing officer f or t he Danebury p roject. Lock a rgues that mainframe c omputers a re p referable t o micro-computers. The l atter a re susceptible t o what h e d escribes a s " resident-expert" s yndrome. H e d ifferenti ates b etween p rimary a nd s econdary i nvestigations. The f ormer control a nd s tructure the i nitial data s et. They i nclude t he i nitial s torage o f the d ata a nd t he r etrieval of basic i nformation. The l atter a re u sually c arried out on subsidary d ata s ets which must b e extracted f rom the p rimary data. They i nclude t he more c omplex t ypes of multivariate s tatistical a nalysis. What i s r ecorded a t the primary s tage w ill d etermine what c an b e u ndertaken a t the s econdary s tage. L ock emphasises t hat i t i s e ssential that r ealistic g oals a re d efined a t the outset. Martin Carver p roposes that the w idespread u se o f computers w ill i nevitably c hange the n ature of a rchaeology. Research w ill b e more s ystematic a nd may b ecome a t eam effort, rather t han the work of the i ndividual. A rchaeology w ill a lso b ecome more expensive, but Carver p redicts t hat t he costs of system d evelopment may l ead to greater specialisa tion o f a rchaeological u nits, o r t o t he establishment o f a c entralised computer f acility. The n eed f or s tandardised r ecording t erms i s s een a s o ne c onsequence o f this. Carver's paper puts f orward a f ramework i nto which i t i s p roposed t hat a ll a rchaeological data w ill f it, a nd r elates t his t o h is current c ampaign of excavations a t Sutton Hoo. Paul

Reilly

i s

a lso

c oncerned w ith the

2

ways

i n

which

c omputers w ill p roduce c hange i n a rchaeology. H e d iscusses some o f the philosophical problems i nvolved i n r ecording a rchaeological data, a nd d escribes t he i mplications f or two i ssues o f computerisation: s tandardisation, a nd a rtificial i ntelligence. H is p aper p rovides a n i ntroduction t o the r emainder o f the volume, where the emphasis i s more on the t heoretical a nd methodological questions, r ather t han t he p ractical

applications.

Malcolm Cooper l ooks a t t he d evelopment a nd p resent o rganisation o f computers i n f ield a rchaeology. He s uggests t hat c onsideration s hould b e g iven t o g reater c entralisati on o f control a nd t o standardisation o f r ecording i n o rder t o i ncrease e fficiency a nd c ost-effectiveness. He a rgues t hat a rchaeology would d o well to l earn some l essons f rom t he

business

world.

A d ifferent v iew i s taken by Julian Richards. H e that s tandardisation s hould n ot b e i mposed f rom

a rgues a bove.

Standardisation o f hardware may eventually evolve naturall y. Standardisation o f r ecording s ystems, a nd t he i dea o f the universal data bank, a re philosophically untenable and may b e damaging t o t he d evelopment o f a rchaeology. Standardisation, however, should not b e c onfused with c ompatability, which h e b elieves i s a good t hing. Gary Lock and Dick Spicer also b elieve t hat the f ield o f c ommerce i s not n ecessarilly a s uitable model f or a rchaeol ogy. They c hallenge some o f the accepted wisdoms about c omputers, which have b een borrowed f rom the business world. I n particular theypropose that micro-computers a re f requently m is-used. They b elieve t hat m icro-computers have p ractical l imitations, but they also a rgue t hat a rchaeol ogists r arely r each t hese l imits, a s t hey u se m icrocomputers

i nefficiently.

F inally, J eremy Huggett takes up t he t heme o f a rtificial i ntelligence with a paper o n expert s ystems. Huggett p rovides a c omprehensive guide t o what expert s ystems a re, a nd h ow t hey have b een applied i n o ther d isciplines. H e d iscusses existing a rchaeological applications, but s uggests t hat their u se i n a rchaeology may b e l imited t o a reas where expert k nowledge i s f airly well-defined. The

editors

do

not

n ecessarily endorse

the

v iews

o f

each

o f

t he i ndividual authors. I ndeed, many o f t he papers a re mutually contradictory, a nd t o a gree w ith a ll would b e i mpossible. H owever, w e d o b elieve t hat t his i s a h ealthy s ituation f or the d evelopment o f c omputer u sage i n a rchaeol ogy. We h ope t hat, by a iring a w ide r ange o f v iews about t he direction s uch d evelopment should take, debate w ill b e encouraged amongst t he a rchaeological c ommunity a s a whole.

3

TOWARDS A COMPUTERISED ARCHAEOLOGICAL RESEARCH ARCHIVE John

Schofield a nd

Paul Tyers

This paper i s i n f our parts: a b rief d escription o f the u se o f c omputers i n t he a rchive o f the Museum o f L ondon's Department o f Urban Archaeology; the k inds o f question that m ight b e a sked o f s uch a n a rchive; a r eview o f the current r ange o f enquiries; and concluding s uggestions < 1>. The i ntention i s t o d escribe our own d iscussion o f the v iabili ty o f s etting up a computerised a rchaeological r esearch a rchive o f t he extensive excavations c arried out f rom 1 973 t o

the

p resent

i n

the

City o f

London.

THE ARCHIVE AND THE COMPUTER I n a rchaeological r ecording, the l evel 3 structural a rchive r eport i s the most extensive d escription o f the l ayer by l ayer h istory o f the s ite. The p rocedures u sed i n i ts c ompilation s hould b e s tandardised w ithin t he unit, a nd i n t he C ity o f London we have prepared a n Archive Report Writing Manual ( DUA 1 985b) to match our S ite Manual ( DUA 1 980). Some s ites, o r parts of s ites, will only merit publication a t l evel 3 , a nd i n extreme c ases, o r when f unds d o not p ermit i t, a n ordered l evel 2 archive w ill have t o s uffice u ntil more funds a re available. But t he majority o f the l evel 3 a rchive r eports w ill b e the solid basis both o f a n a ctively c urated a rchive a nd t he c onventional l evel 4 publication programme. We h ave experimented a t a ll l evels o f the a rchive w ith computers. The Museum o f London's computer f acility was s et up by Kevin F lude, w ith advice f rom I an Graham, i n l ate 1 981. The specific s timulus was the i mmediately f orthc oming Billingsgate excavation, which l asted 1 3 months f rom January 1 982 and p rovided a t esting-ground f or the development o f excavation a nd f inds r ecording by c omputer. The s ystem p resently comprises a P DP 1 1/23 minicomputer with XENIX operating s ystem a nd 8 Shelton S ig-Net m icrocomputers p laced a t workplaces throughout the Museum, i ncluding i ts s atellite o ffices, f or data c ollection a nd word p rocessing o f r eports. We have r ecently also acquired two Epson P X-8 l ap-held c omputers f or t he s ame purposes i n s ituations where conventional d isc-based machines a re i nappropriate, i .e. o n s ite o r i n f ar-flung Museum s tores. This data c ollection f unction was extended t o the excavation s ite o n Billingsgate, where s trata were i nput during s ite r ecordi ng. This experiment i n r ecording c ontexts s traight i nto t he computer a nd i n e ffect d uplicating the paper r ecord has y et t o b e evaluated f ully, s ince the i ncreased e ffecti veness o f a nalysis by t he c omputer must b e t ested by a ll departments using the a rchive the supervisor i n writing u p, t he f inds a nd environmental a nalysts. F irst i mpressions s uggest t hat f or medium a nd l arge s ites ( over 3 000 c ontexts), t he c omputer c an s ave t ime i n a nalysis o f -

-

-

5

i nformation considerable

which would otherwise b e r epresented p iles of context s heets a nd p lans.

by

I t i s c lear that many types o f question can a nd should b e a sked o f a detailed a rchaeological r esearch a rchive. They can b e roughly d ivided i nto two k inds: t hose which c an b e a nswered by a s imple manual s earch through the a rchive r eports or f inds s tores, and those which c annot. By the f ormer group we mean a r equest f or a specific s ite r eport, p erhaps running to s everal hundred t ypescript pages and accompanying drawings; o r a s ection of a r eport where t he enquirer knows ( or has f ound out b y r eading the r eport i tself) exactly what i s r equired. P roviding s uch a s ervice within the paper archive i s a matter of adminstration and t he s ervices of a n a rchivist o r l ibrarian. S imilar ' simple' s earches through a f inds archive may b e possible when the a rchive i tself i s small; but the s ize o f our a rchive i s already s uch t hat we a re f inding t hat a computer i s n ecessa ry t o r ecall the p recise l ocation o f even t he most memorable material. C ertain guides c an b e compiled to a id b rowsing o r examination of the a rchive r eports. The f irst l evel of guide must be a n A rchive Catalogue, which b riefly s tates the main f indings on each s ite, l ists the a rchive r eports ( structural, f inds, environmental) g enerated f rom i ts material, and the l evel 4 r eports, both i nterim and compreh ensive, which have r esulted. I t i s hoped t o have o ne f or the DUA s ites of 1 973-82 r eady i n 1 985 ( DUA 1 985a). Many enquiries w ill b e answered by consultation o f the a rchive r eports, without further r esort to the l evel 2 a rchive material, whether r ecords o r f inds, b ehind them. The s econd l evel o f enquiry, o ne not s atisfied by the l evel of detail i n the r eports, w ishes to i nterrogate the descriptions of t he data, especially on the f inds. A lthough ' another experiment i n r ecording s tratigraphic data o n s ite i s possible i n the n ear future, our current efforts a re d irected t owards computerisation i n p ost-excavation, a nd the main progress h ere has b een i n f inds analysis. I nforma tion on a ll the f inds f rom current s ites i s entered o n the computer a s a matter of course, a nd the r ecord has b een extended to cover s ome s ites excavated b efore c omputers were available. A h ierarchy of data types i s available. The s implest l ist t he b road a rtefact c lasses ( Roman pottery, animal b one, post-med building material) o r objects o f particular i nterest ( Coins, metalwork) i n each context, but more d etailed i nformation o n some o f t hese c lasses i s a lso h eld; t he exact t ypes o f pottery f rom a Context, or d etailed measurements o f a rtefacts s uch a s s hoes. Where quantified d ata i s c ompiled, t ables a nd h istograms showing differences b etween contexts or b etween s ites a re g enerated quickly and easily, a s a n a id t o chronology and other f ields o f i nterpretation. The of

t he

most

p ractical

computer

a t

a nd

p resent

i ndeed most i s

t he

6

n ecessary

construction

o f

f unction i ndexes.

These enable the r esearcher, whether a c olleague f rom the f inds o r environmental s ection o r a n outside enquirer, to examine material f rom a number of complex s ites. There s eem to b e two options h ere: i ndex the abstract o r s ummary o f the archive r eport, o r i ndex the actual t ext. We are about t o experiment w ith the i ndexing, by a qualified b ibliographer, o f a t rial r un o f a rchive r eports to d ecide which i s p referable. Word processing o f a ll l evel 3 r eports within a unit i s now a v iability; but t he p resent quality o f r eading, a nd t herefore i ndexing, o f f ull t ext by Optical Character Recognition machines i s s till i nsufficient. I t therefore s eems more p rudent t o opt f or t he i ndexing o f fairly f ull abstracts.

THE KINDS

OF QUESTION

AN ARCHIVE MIGHT ANSWER

What a re these questions which r esearchers might b ring to the a rchive? To s tructure the i ndexes correctly, w e have t o l ook partly a t t he way i n which the i nformation was put i nto the r ecord a nd t he p rinciples b ehind data-gathering, s o that our enquiries n either stretch nor underestimate the data, a nd partly a t the l ikeliest k inds o f question that might b e put. The paragraphs which f ollow outline our c urrent i nternal d iscussion. The

s ite

i nformation

i s

o rdered

a t many

l evels,

f rom

the p ercentages o f various constituents i n a l ayer to the j uxtaposition o f s everal d iscrete but c ontemporary s ites i n a named s treet o r a rea o f town. At a h igher l evel t he computer should b e able t o generate d istribution maps o f a ny specified i tem, such a s special a rtefacts, house-types, churches o r s ites of excavations. Functions of r ooms o r buildings c an b e d efined by a rtefacts o r by the t echnologi cal p rocesses b etrayed by i ndustrial s crap, but often t here a re more a rtefacts i n the dumping l ayers b etween floors t han o n o r i n the f loors themselves, l eading t o misleading a ssumptions. Roman t imber buildings, w ith f requ ent f ires, appear t o offer t ighter a ssemblages. For the m edieval p eriod, c esspits, i f not c leaned out by t heir u sers, can offer good c eramic g roups ( Vince 1 985). Defining workplaces by s tudying the s tructure o f a building, wholly o r i n part, i s easy i f there a re c lear t races, u sually o f h eavy i ndustry, but i n many Roman a nd medieval b uildings r ooms c ould a ssume a variety o f f unctions, a nd often d id over s hort p eriods o f t ime. C ertain buildings c an b e i denti fied by structural a ttributes ( e.g. hypocausts) o r d ecoration; t he purpose o f rooms may b e d educed f rom their p lan f orm, access patterns or p roportions ( e.g. P erring 1 985 on Roman u rban domestic buildings). Particular parts of buildings, s uch a s shops o r c ellars, a re g enerally only f ound i n quantity i n u rban c ontexts a nd c an f orm the basis o f a s tudy of u rban building f orms. Between t he building a nd the t own there i s a n i ntermediate l evel o f a nalysis, t hat o f t he u se o f space w ithin t he property i n which the buildings o r s tructures l ie. The

7

d istribution of p its which may b e d ivided i nto functional groups on their shape, s ize and p rimary backfill may r eveal spaces f ormerly occupied by buildings, s how the e stablishment of p roperty boundaries o r contain specific c oncentrations o f i ndustrial waste. H ere however s ome caution may b e r equired, s ince u rban rubbish of the s ame date t ends to b e o f s imilar character r egardless of whether i t ended up i n a domestic p it, the c ity d itch o r the waterf ront r eclamation z one. Thus mapping o f a rtefacts i n s econdary contexts may not produce satisfactory r esults. F inds i n dump d eposits a re u seful f or g eneral hypotheses rather than particular topographical s tatements. -

-

We c an t herefore o rder the questions i nto types, a rranging them h ierarchically f rom the c lose-up of the l ayer o r pot to wide-ranging topographical, economic a nd social hypotheses. H ere a re some examples: ( a)

At the

l evel

of

the

a rtefact o r

1 . A specific a rtefact: f rom Milk Street. 2 . All s tirrups f rom s earch a ll the s ites). 3 . All s amian bowls r esidual contexts.

of

s ingle

the

t he

Saxon

p eriod

f orm Dr

4 5

4 . All arched s tone f oundations, d ivided i nto s ecular and r eligious ( b)

At

the

l evel of

5 . A specific carpenter's axe

t he

f eature

f eature: f rom Milk

or

i n

context-type: c arpenter's

1 200-1330

2 nd

axe

( i.e.

century non-

o f whatever p eriod, s tructures.

a rtefact g roup:

t he p it i n which the Street was f ound.

Saxon

6 . I nferences about s ocial s tanding f rom a specific medieval c esspit g roup of pottery, g lass and wooden a rtefacts. 7 .

( c)

b ridge

abutments

t imber

o r

8 .

All

c hurch windows

9 .

All wattle-lined p its,

1 0.

ed by

All

s treet o f

a rtefacts 1 1.

A

over

whether

o f

-

h ow were o r

o f date. t hey

l aid?

l and-use,

a s

d efin-

c haracteristics:

b lacksmith

g roup

a cross.

p reference

s tructural

tools,

8 '

r egardless

surfaces

a rtefact or

A ll

workplaces, 1 2.

s treams,

stone.

Roman

Patterns

over

a ssemblages

( slag

d ebris,

shops).

o f moulded

8

s tones

f rom a named

p arish

c hurch a nd churches. 1 3. All r eligious

t heir

connections

w ith

1 5th c entury pottery houses.

i n

s tones

i n

o ther

p rimary deposits

i n

1 4. Evidence ( structural or a rtefactual) f or t he a rrival o f the Blackfriars i n the a reas known o n documentary ground to have b een occupied by them f rom c .1275. 1 5. All excavated

medieval domestic s ince the War.

1 6. Alterations c 1 250-c.1550 .

t o

buildings

the

C ity

t he

Great

i n

gates

Thames

a nd

S t.

d efences

.

1 7.

The

a rchaeology of

1 8. The medieval shoe t ools, workplaces. We can s ee that t hesis-length a nd

i ndustry:

a t this l evel we complexity.

F ire

o f

shoes,

a re

London, l eather

1 666. waste,

posing questions

of

Choice of s oftware to i nterrogate the archive i n t his way d epends upon the computer; o n the other hand, i f we t hink t his i s a major direction t o f ollow, then the s oftware r equirements govern the choice o f c omputer. At a n experimental l evel existing database management s ystems s uch a s dBase I I ( and now, dBase I II) s how that questions o f t his k ind can easily b e a nswered ( figure 1 ).

RECENT ENQUIRIES

OF THE MUSEUM OF

LONDON' S ARCHIVE

A t . this p oint i t i s appropriate t o a sk f or a s tatement o f p rogress with the embryonic computerised a rchive i n L ondon. What k inds o f question have b een a nswered s o f ar, and h ow f ar i s t he scheme outlined a p ractical possibility? The

range

of

enquiries

that

can

b e

a nswered

by

the

data i n the a rchive a nd i ndeed most r equests f rom other d epartments of the Museum a nd f rom outside bodies and i ndividuals a t p resent f all i nto this c ategory a re o f the ' Do you h ave a ny examples o f artefact type ' X' f rom y our excavations?' variety. A s imple i nterrogation o f t he computer w ill r eveal the numbers, p rovenances a nd t hus p resent s torage l ocations o f a ll examples o f ' X' amongst t he 5 1000 currently h eld r ecords. The i nformation i s more c omplete, more consistent a nd more quickly p roduced t han t he equivalent i n p re-computer days. The ease a nd speed o f p roduction a re i mportant considerations f or a D epartment w hose primary r esponsibility does not currently l ie i n c atering f or s uch r equests. -

-

Before

o r

a fter

examination

9

o f

the

i tems

i n

questior

G erard's H all B ishop o f C hichester

B asing L ane C hancery L ane F enchurch S t H olborn M incing L ane P ancras L ane S outhwark S t M ary a t H ill T hames S t T hreadneedle S t

D arcy 1 17 F enchurch S t g r B ishop o f E ly C lothworkers' H all 3P ancras t h 1 B ishop o f W inchester A bbot o f W altham S eal H ouse B uilding F M erchant T aylors' H ail [ the d Base c ommand i s:

d isplay s ite,address f or docfm < 1300 . and . ' hall '$Mrooms . and . m easure ]

F ig.1: two e xamples o f s imple q uestions p ut t o a d Base I I d atabase f ile o f S MR-like r ecords o f 2 50 m edieval h ouses i n t he C ity o f L ondon . A bove , " list a ll t he h ouses i n t he f ile w hich a re k nown f rom d ocuments b efore 1 300, which h ad h alls f or w hich w e h ave p lans" i .e . t hree c onditions t o t he q uestion . B elow, u se o f t he s ub-string f unction: a small p rogram c onstructs t he h istory o f t he p arlour b y c iting d ated e xamples i n c hronological o rder. I t c an do t he s ame f or o ther r ooms a nd f eatures s uch a s t he h ail, k itchen, g arden, o riel window; o r materials ( stone, b rick, t inber). -

1 310 c ontract G oldsmiths' H all 1 383 c ontract A ddle L ane D rapers' H alll G rocers' H all C arpenters' H all C utlers' H all P ewterers' H all B lacksmiths' H all B ishop o f W inchester F ishmongers' H all D udley's h ouse C annon S t A bbot o f B attle P arish C lerks' H ailI D rapers' H all I I B utchers' H all

p ar 1 1 310 1 st f loor p ar l 1 382 p ar 1 1 383 1 st f loor p ar 1 1 425 p ar 1 1 429 p ar 1 1 442 465 p ar 1 1 490 p ar 1 1 p ar 1 1 496 500+ a rch p ar 1 1 p ar 1 1 500+ 509 ( 2 ) p ar 1 1 528 p ar 1 1 p ar 1 1 543 p ar 1 1 544 * oriel p ar 1 1 545 566 *v i ew s p ar 1 1

L eathersellers' H all I I S kinners' H all A rmourers/Braziers' H all

p ar 1 1 580 p ar 1 1 585

C lothworkers' H all 3P ancras L ane 1 D arcy 1 17 F enchurch S t O ld F ishmongers'

p ar 1 p ar 1 p ar 1 p ar 1

H all

1 0

1 594 1 610 1 612 1 618

* plan * plan * pla n s * plan

f urther i nformation may b e r equired. F rom most r ecently excavated s ites i t i s possible to r etrieve l ists of a ssoci ated a rtefacts, such a s dateable p ottery, c oins, c lay p ipes etc. on the basis of which the s cope of the s earch may b e l imited to, f or i nstance, o nly i tems o f c ertain dates o r f rom particular c lasses of context. Unfortunately t he r elevant i nformation f rom many earlier excavations, a nd f or much of the e quivalent material i n the Museum 's non a rchaeological collections, was n ever adequately r ecorded, o r i ndeed subsequently d iscarded. For most enquirers this i s currently the most that i s r equired the computer a rchive i s s een a s a ' pointer' i nto t he physical a rchive o f the a rtefacts themselves, a means o f s electing and s orting the l atter p rior to the examinati on of the objects. When, eventually, d etails o f the objects i n the curatorial ' period' departments o f the Museum ( who hold the material f rom pre-1973 excavations and c asual f inds) a re available on computer, s uch a s earch w ill g enerate l ists o f a ll available objects of a particular type and not merely those f rom r ecent archaeological -

excavations. The a rea of r esearch where computers have made most advances w ithin the Department i s p robably i n the processi ng of c eramics ( Tyers and Vince 1 983). The d eeply stratif ied a rchaeology of London y ields enormous quantities o f pottery o f all p eriods, which has b een r ecorded i n a two s tage p rocess. Within a s hort p eriod o f i ts r ecovery all pottery i s v iewed by the ceramics specialists who produce a s imple qualitative l isting o f the types ( fabrics a nd forms) p resent i n a ll g roups, together with a n a ssessment of the date o f the a ssemblage. This i nformation was o riginally r ecorded on s imple i ndex cards, but these have b een supers eded by the u se o f small portable computers ( Epson P X-8) and l ater t ransfer to more p ermanent s torage within the Museum. The ' spot-date' r ecords a re o f b enefit both to the excavators o f t he s ite and t o the study of London's c eramics a nd over 5 0000 i ndividual r ecords o f this t ype have b een collected f rom s ites excavated s ince 1 981 b efore that date the r ecord i s o nly partial. For many s ites, particularly those excavated with l imited funds, i t i s not possible to analyse a ny pottery i n more detail a nd the ' spot-dates' w ill p robably s tand a s the only available -

i nformation

on

t he material.

As they s tand, l ists o f the occurrence of particular p ottery types a cross many s ites i n the C ity can b e g enerated f rom the ' spot-date' r ecords. Without further p rocessi ng many i nteresting patterns c an b e observed i n this data f or i nstance, c ertain types a re c learly more common i n a reas n ear the waterfronts than o n ' inland' s ites. S imilarl y i t i s possible to r etrieve l ists o f pottery f rom c ontexts o f particular types, such a s c ollections of smashed or burnt pottery, o r l arge g roups o f a specified date. -

However,

f or

more

d etailed

1 1

i nformation

a nother

source

o f i nformation i s available. P ottery s tudied a s part of a publication p roject i s c lassified a nd f ully quantified by both weight a nd v essel equivalents. A fter t he i nitial r ecording, t he r elative quantities of d ifferent wares f rom s ites o r phases c an b e calculated w ith ease, t he r esults b eing presented a s tables o r s imple h istograms. S imilarly i t i s a s imple task to analyse the d istribution o f a s ingle ware or g roup o f wares expressed a s a p ercentage of any other combination of wares, a cross a s eries of s ites o r phases. The quantified and ' spot-date' data complement one a nother the l atter l acks t he detail, but covers a l arger s eries of s amples than the f ormer. O ften the ' spot-date' r ecords can p oint t o the s ites a nd a ssemblages whose detailed analysis may shed l ight o n a particular d evelopment of i nterest. -

A s a n example of this system i n action we could d raw a ttention t o a n a nalysis of some of L ondon's v ery earliest pottery ( Chadburn and Tyers 1 984). The p re-Flavian a ssemblage f rom the 1 983 excavations a t 5 -12 F enchurch S treet i ncluded l arge quantities of a coarse o range/brown f abric which had b een previously noted i n 1 982 a t a small s ite i n Sugar Loaf Court i n a nother part of t he C ity the f abric's l ocal origin was s uggested by t he r ecovery of a s mall number o f wasters a nd other k iln waste a t t he l atter s ite. However,with the exception of F enchurch Street the f abric was v irtually unknown elsewhere i n t he C ity. The ' spotdate' r ecords f or the contemporary l evels o n a number o f s ites i n various parts of the Roman t own were r etrieved and the r elevant material was quantified i n d etail. The r esults, i nitially tabulated but l ater t ransferred t o a map ( not a s y et computer g enerated) d emonstrated wide d iscrepancies i n t he percentage of the l ocal f abric i n g roups across the C ity, w ith particular concentrations i n the a rea of the f orum a nd i n the v icinity o f the p resumed k ilns ( figure 2 ). -

A rather s imilar approach was t aken w ith a l arge p it containing pottery o f the m id-second c entury AD ( Tyers 1 984). I t was noted t hat the d istribution of pottery f orms i n the group was rather d ifferent to that f rom contemporary groups on other s ites. Direct comparison s uggested a n over-representation o f bowls a nd r elatively smaller numbers of b eakers a nd j ars. The a ssemblage, which s eemed t o h ave b een d eposited a s a s ingle event rather t han a ccumulated over a l onger p eriod of t ime, was a ssociated with a r ather unusual range o f animal bones, a nd taken t ogether a s imple functional i nterpretation of t he contents o f the p it a s the debris f rom a ' cookshop' or s imilar establishment c ould b e attempted. A s a non-ceramic example we c ould c ite a r ecent s tudy of medieval knives, some 3 00 i n a ll, f rom waterfront s ites i n t he C ity o f L ondon. The a im was t o s tudy the d evelopment of knife typology a nd manufacture f rom c . 1 140 t o 1 460. Each r ecord c ontained c . 3 0 elements, i ncluding d imensions, materials, s hapes etc. The principal u se of the c omputer

1 2

F igure 2 : M ap o f t he C ity o f L ondon, i llustrating t he d istribution o f l ocally-produced S ugar L oaf C ourt w are t hroughout t he R oman c ity . H ere o nly t he s tatistics h ave b een g enerated b y c omputer, b ut f uture p ossibilities i nclude c omputer-generated m aps o f s ites u sing g rid r eferences.

H

I ,

F 0 U

13

the changing patterns o f these elements against t he f ive t ime periods r epresented, patterns t hat altered f requently a s i tems were added to o r r emoved f rom the g roup, o r a s dates a nd i dentifications c hanged ( pers comm Jane Cowgill). A r elated example i s the c reation o f a c ross-reference table i llustrating the t otal numbers of d ifferent c lasses o f objects by p eriod and s ite ( figure 3 ). I t would also b e possible t o compare the d istributions of pottery types with that o f other c lasses o f a rtefact, o r attempt a correlation b etween pottery a ssemblages a nd type o f deposit. The r equests, and the r esults, outlined a bove would have b een r ecognised by archaeologists working i n p re-computer days. We a re not a s y et having to c ater f or r equests whose nature has i n any s ense b een generated by the computerisation of the archive i tself; rather w e a re fulfilling demands which could have b een a nswered by paper r ecords, a lbeit with consideraby greater effort a nd r esourc es r esources that would not a lways have b een available. -

CONCLUSIONS There w ill i nevitably b e some t ime l ag b etween the availability of i ncreasing quantities of a rchaeological d ata i n machine r eadable f orm a nd the development o f models a nd hypotheses to b e t ested with this material specifically i n m ind. This i s not a computer p roblem per s e but rather l ies with d evelopments i n methodology a nd theory of a rchaeology i tself, f or only there w ill a rise t he questions t hat the masses of i nformation now b eing collected w ill b e able t o a nswer. But there a re of course dangers. The i ntention, i f not c ertainty, t hat the i nformation r ecorded t oday w ill c ontinu e t o b e available i n a rchives l ong i nto the f uture a lso throws on t hose collecting the r ecords the r esponsibility f or ensuring their v alidity. We w ill u ndoubtedly s ee t he s ituation i n the future where r esearch s tudents a nd o thers w ill prefer t o a nalyse a g roup o f material t hrough t he extant computer r ecords rather t han by r e-examining the o riginal material. C learly i f these a re not correct i n t he f irst p lace, chaos a nd great damage w ill e nsue. The i mpact o f c omputerisation a t t he ' sharp end' o f a rchaeology has y et to b e f elt, and the r esults c annot b e f ully p redicted. The unforgiving nature o f computerised data s hould l ead u s to b e b etter archaeologists approaching p roblems i n more c onsistent a nd r epeatable ways a nd building i n s ystems t o cope with uncertainty r ather t han s weeping i t under the c arpet. This will a llow more t ime t o a nalyse p roblems t han f or coping with a dministrative d etails o f s toring a nd r etrieving i nformation. -

I n s um, we l ook t owards t he n ear f uture when a c omputerised a rchaeological r esearch a rchive i n L ondon c an b e i nterrogated to a f ine l evel; a nd s uggest t hat the e ffect-

1 4

F igure 3 : C omputer-generated a nd p rinted t able i llustrating t he d istribution o f d ated m edieval s cabbards, s cissors, s hears a nd k nives f rom v arious s ites i n t he C ity o f L ondon ( work b y J ane C owgill). A s t he v ariables o f d ate, p eriod a nd n umbers o f e xamples c hange d uring r esearch, t he t able c an b e r egenerated.

I 4STRAT B C72

P 1 02

IP ERIOD 2

1P ERIOD 3

IP ERIOD 4

IP ERIOD 5

IP ERIOD 6

I

I 2K NIVES I I5 S CABBARDS I I I

I I I I

I 9 KNIVES I2 3 S CA P EARDS I1S HEARS I

I6 2 KNIVES I7 S CAPP .A RDS I1S CISSORS I13 SHEARS

I

I

I I I

I I I

I I

I 3 KNIVES

I 2 KNIVES

I3 K NIVES

I2S CABBARDS

I

I4 S CABBARDS

I

I I

I I

I

I6 S CABBARDS

I I

I

I I

R 1S82 P t d883

I PERIOD I

I

I

I

+

I

I

I 2 KNIVES I I 4 SCABBARDS I IIS CISSORS I -

I

4 -

+

IIK NIFE

I

+---- --------+

+

CU573

PI SHEARS

I 4

+--- -- ----- --+

I

I

+

I

11 00 K NIVES I IR AZOR

I1K NIFE

I

I

I

I

I2 1 S HEARS

I

+

+

+

+

I

I

I

IB K NIVES

IIK NIFE

I

I

I

I

I1 3 S CABBARDS

13S CABBARDS

I

I

I

I

-4----- ------+

D (J (77 I I --- -I--- ------+

I1 SHEARS

+

I

+

I

I

+

I

IIK NIFE

I

+

+

------------+

+

I1 K NIFE

F LE82 -4

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-+

-+

I1S CABBARD

I

IIS CABBARD

+

1W82 I I S CABBARD I O PTBI I I B ED I I

I +

I +----- - -

I 4

I

I

I7 S CABBARDS

+

+

I

I

4---- --------+- -------

I +

I2 S CABBARDS

4

+

I +

I

I

+

I 4

I +

I

+

I

I

4 -

+

IIK NIFE +

I +

I

I

+

+

I +

+

I2 K NIVES

I7 K NIVES

I

I

I 2 KNIVES

I

I

I

I

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I

I

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I

I

4 -

4

S I JABi

1 L74

11 )78

4-- ----------+

I2 SHEARS +

I 8 KNIVES I6 K NIVES 14 K NIVES I2 S CABBARDS I I S CARBAR I ) I 1 SCABBARD I 1 SHEARS I 1 SHEARS I IS HEARS

4

I

I +

I2 K NIVES

I

I

I

5 1 474

+

I

I --4

14 K NIVES I

-4

I

I

-+

I +

P 0M79

I

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4

I I

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+

+

-4 -- ----------+

+

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I I S CABBARD

I

+

I

+

I --+

I

-

IIK NIFE

I

L N74

I +---

I

-4

4

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+

11 9 K NIVES

I1K NIFE

I1 R AZOR

I

-

1 3 KNIVES

+

I +

I1 3 K NIVES I1S CAP[ 'ARD

I1 3 S CABBARDS I

+

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+

+

+

+

+

4

IIK NIFE I 1 SCABBARD I 1 SHEARS I I

I

I

I3 S CABBARDS

i1 8 K NIVES I IS CA BARD I IS CISSORS

I1 2 K NIVES 11 4 K NIVES I I3S CA BARDS I I S CAEFARD I I 1 SHEARS I4 S HEARS I

I I S CABBARD

I I

I

+-- -----

I

I

I +

I

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+

+

I

I

4

+

1 5

I 4

I +

+

I 4-----

4

I +

+

by the development o f s imilar a rchives elsewhere, a t l east for h istoric towns. We l ook forward also t o the exchange of a rchaeological i nformation of a ll k inds f rom computer t o computer, perhaps by means of a rchaeological bulletin boards i n the major u nits a nd r esearch i nstitutions.

ENDNOTES 1 . The paper a s p resented a t t he conference by John Schofield i s to be published elsewhere ( Schofield 1 985). When publication of these proceedings was agreed, a n ew paper based i n part on that presented but taking the arguments i n i t a s tage further was commissioned.

REFERENCES Chadburn,A. a nd Tyers,P. 1 984. Early Roman P ottery Fenchurch Street, DUA l evel 3 r eport, April 1 984.

f rom

DUA 1 980. D epartment o f Urban Archaeology, S ite Manual: Part 1 , the Written Record, Museum o f London, 1 980. DUA 1 985a.

D epartment

Directory,

Museum o f

DUA

Department

1 985b.

Writing

Manual,

Perring,D. J .

and

1 985.

Schofield,J.

i n

Britain,

o r

' Roman ( eds.),

1 985.

( ed.),

Schofield,J.

Urban

Archaeology,

Archaeology,

London,

Domestic

Buildings'

i n

Schofield,

' Excavation

a rchives

i n

London'

i n

1 985.

a nd

L eech,R.

( eds.),

1 985.

Urban

Archaeology

CBA Research Report.

1 984. London

Tyers,P.

and Vince,A.

1 983.

' Computing

Archaeologist,

4 .11,

2 99-304.

' An

a ssemblage

( ed.),

of

Archaeologist

Vince,A. 1 985. ' The s tudy of excavations' i n Schofield,J.

and Museums,

Report

1 985.

London',

White,A.

Archive

1 985.

Tyers,P.

London

Archive

1 985.

Urban

Museum o f

L eech,R.

White, A.

of

London,

1 985.

Dust

Society of

Roman

4 .14,

c eramics

f rom

3 67-74. the

DUA pottery'

pottery f rom u rban and L eech,R. ( eds.),

to

Dust?.

-

F ield

A rchaeology

Museum Archaeologists,

1 6

1 985.

1 985.

TEN YEARS OF DATA-PROCESSING IN THE CENTRAL EXCAVATION UNIT

John Hinchliffe and Joe Jefferies When the Central Excavation Unit was established in 1975 it was intended from the start that an automatic data­ processing facility should form an integral part of its operation. For this reason the primary paper records were of a form which allowed them to double as data-input documents. The principles of the system were outlined in Jefferies (1977). Although t syitem has undergone mo..di_f ication since its adoption its aims remain as state'd in that document. 1. To formulate a standard which could apply to all Central Excavation Unit records irrespective of the type of excavation. 2. To ensure computer input sytem to store, these records.

the compatability of these records for and to design an automatic data-handling re�rieve, check, analyse and disseminate

3. To set up and maintain an extensively indexed archive to form a basis for specific enquiries and research, and to consider methods by which the archive may be disseminated. The need to adopt a highly systematic approach to the collection, analysis, storage and dissemination of information from excavated sites arose from the 'data explosion' of the late 1960s and early 1970s - the product of a substantial increase in the numbers of excavations, with more detailed recording systems, producing a greatly extended range of material regarded as informative•. Two specific points relating to the CEO system be stressed at the outset:

should

1. Although a series of pre-printed pro-formas containing a suite of fields make up the primary documentation we have been concerned that the requirements of the data-processing system should not restrict the recorder. For this reason additional fields may be used as required and free text has always formed a significant part of the record. 2. The underlying concept of the recording and data­ processing with regard to the relationship of individual contexts is that of a structural hierarchy rather than a purely stratigraphic sequence. Although the latter is inherent in the accumulated data base it has always been our practice that the record, and the concept of 'context' extends beyond this, e.g. a post hole (one context) may be re�orded as part of a structure Cone context).

17

HISTORICAL SUMMARY

Back in 1975 CEU began by making use of a commercial time­ sharing service - Honeywell Mark III, based in Cleveland, Ohio. Under this system data was transferred on to paper tape using a teletype before being read into a temporary computer file using a tape reader or the teletype, via a Modem and GPO lines. It soon became clear that the inherent e�pen�e of this system, together with the problems with associated telecommunications networks by no means represented the right solution for what we were attempting and by 1977 the very rapid developments in microprocessor technology meant that the processing of archaeological records by an inexpensive desk-top computer was becoming feasible. The advantages of such a system in terms of economy, accessibility and independence were seen to be considerable. We therefore acquired a Research Machines 380Z micro­ computer which was just beginning production at the end of 1977 and, being based on the then new Zilog Z80 microprocessor was, for its time, an exceptional machine. No disc drive was then available so the machine was first used with cassette recorders as the mass storage medium. This greatly restricted the capabilities of the machine and thus it was used mainly in conjunction with the existing time-share facility. Some months after the initial purchase a twin floppy disc system became available and the 380Z was upgraded accordingly. The RML 380Z has CP/M as its disc operating system and this has since become the de facto standard for most micro­ computers of this specification. Although this configuration produced for its time unprecedented computer .power for its cost software developments had lagged behind ·those of hardware . and there was a paucity of suitable software at the time the computer was first purchased. The only languages then available were a simple assembler and a BASIC interpreter. Although more suitable languages subsequently became available we were by that time sufficiently far on with the implementation of the application software that recoding was not a viable proposition. The CEU has undertaken excavations on a wide variety of sites throughout the country. Almost all of these excavations have had their data processed by computer, the majority on the 380Z. This work has involved the processing of 80,000 to 100,000 structural records and several hundred thousand artefact records. In spite of the sterling performance of the 380Z it became clear over the past couple of years that a more sophisticated system was required. Not only was the comparative age (in computer terms) of the equipment a factor but also: 1. The quantity

380Z did not have the capacity to store the of data generated by the larger CEU excavations 18

and hence comprehensive analyses of the data from these sites could not be undertaken, to the detriment of both archives and reports. 2. The equipment was only accessible to one user at a time, whether for programming, data-input, data-processing or printing. There was little opportunity for staff engaged in post-excavation work to work on their data interactively - all editing and analysis had to be done through the cumbersome format of print-outs. SEEKING A SOLUTION

In view of the problems outlined above we set in train a process of investigation to find a system which met our needs. Our terms of reference were: 1. The system must be capable of storing large amounts of data (from 30 - 50 megabytes). 2. The system must be simultaneously accessible to several users. 3. The system must be capable of running all existing CEU software without modification. 4. The system must have a large directly addressable memory to allow the stratigraphic and structural relationship processing to work for the data from the largest excavations. A suitable facility was found in the form of the DMS HI-NET network system consisting of a server, six workstat­ ions and a hard disc storage system. In theory at least the system is capable of storing 46 times the amount of Its principal impact data its predecessor could handle. on CEU practice will be the availability of workstations for interactive use, which together with a revised suite of programs presently in preparation (CEU forthcoming) will allow greatly extended personal machine use by more of the unit staff than has been possible in the past. The most fundamental change in the new software is to replace the present sequential filing system with a proprietary data-base system. This will mean that individ­ ual records and groups of records can be quickly and easily retrieved from the data-base. It is intended to provide an interactive editing facility so that a new record may be created and immediately added to the data-base or an exist­ ing record may very easily be displayed on the screen, edited and replaced in the data-base. This editor is to be a screen editor similar to WordStar in action but working specifically on the records in the data-base. The previous system was not designed for non-expert use. The new version will be entirely menu-driven so that 19

at every step the user is offered a number of choices to select. The documentation will take the form of a number of files which may be printed out in whole or in part and are instantly accessible on the screen during processing. The extension of 'non-expert' use implicity in the new facility will also require safeguards against accidental loss of data and hence will involve the concept of users of Instead of BASIC the new system will different privilege. use language C which has a very logical structure and is easy to document and maintain. CEU DATA-PROCESSING IN PRACTICE Five 1.

discrete processes can be identified in CEU

practice:

Input

Context sheets, artefact sheets, sample and skeleton record sheets are completed or begun on site (for details of the recording system see CEU 1985). The records entered under the 72 defined fields on the recording sheets are typed on to disc at the CEU base to create the primary site data­base. Original paper records are maintained unaltered - as part of the archive. 2.

Editing

Once the primary data-base has been created it can be interrogated. At this stage the most significant program, for the structural record, is that designed to check reciprocity between relationships so that omissions and errors can be rectified. Clearly this form of error­ c�king is essential before any form of analysis is attempted. The process of editing and error-checking is of course not a once-and-for-all event but continues so long as the data-base is under active enhancement. 3. The

Enhancement results of the various analyses undertaken within

the

terms of the post-excavation research design are added to the data-base. Hitherto this has been undertaken by the typing-in of additional data which is accomplished by addition to the original record sheet by the specialist, conflation with a data-base created by the specialist, or through the design of a pro-forma for 'common artefact records' - the most commonly used·in the processing of pottery. In the latter area we are currently examining the potential of transferring characteristic data and other information directly on to the data-base using computer­ linked scales and a graphics pad. 4.

Analysis

Once the data-base is completed it can be interrogated and sorted on the basis of any field or combination of fields. 20

It is in this area that the new facility will be particular benefit in fully exploiting the potential automatic data-processing. 5.

of of

Dissemination

At the completion of the process the data resulting from the original records, their enhancement and specialist analyses is stored on disc. As such it is capable of dissemination in three forms - computer print-out, The first of microfiche and on disc (or magnetic tape). these would conventionally form part of the archive as a series of catalogues. The drawbacks are, firstly, the bulky nature of the material and, secondly, the fact that the manner in which the data is presented is 'fixed' and hence fails to exploit the full potential of the machine base. The second form of presentation, microfiche, obviously avoids the problem of bulk but the data contained within the fiche is subject to the same constraints as the paper record. The third form of dissemination is by magnetic disc or tape. The major advantage of this form is that it will allow a future user of the archive to direct himself/herself directly to the data if suitable equipment is available. It is in this sense a 'live' archive. There are of course technical problems, given the diversity of systems and there remains the question of the 'shelf life' of the magnetic storage medium but these are by no means insuperable. Attention must be given to this aspect of the storage of archives as it will be a great pity if data­ bases compiled at considerable cost and capable of interactive interrogation are literally allowed to fade away leaving only fixed catalogues of data for future . researchers. REFERENCES

CEU 1985. Central Excavation Unit Manual: Part 2: Recording. HBMC(E). CEU forthcoming. Central Excavation Unit Manual: Part 3: Processing and production of archives and reports. HBMC ( E). Jefferies,J.S. 1977. Recording systems in use by the Central Excavation Unit. DAMHB Occasional Paper No. 1. HMSO.

21

RANDOM ACCESS

AND DATA COMPRESSION WITH REFERENCE TO REMOTE DATA COLLECTION: 1 AND 1 = 1 Dominic

Powlesland

That the micro-computer should p lay a major role i n the c ollection, s torage a nd a nalysis o f a rchaeological data i s now w idely accepted, although exactly how and a t what point i n t he p rocess o f data c ollection t his n ew t echnology should b e applied has y et t o b e agreed. There i s amongst many a d egree o f c aution r egarding t he application o f computers i n the management o f a rchaeological data, c aution a rising out o f a n awareness o f early u nproductive applicati ons, a l ack of c onfidence i n hardware that i s already out o f date when i t appears i n the s hops a nd f inally, a l ack o f confidence i n the c omputer's ability to r etain l arge quanti ties o f data a s opposed t o the paper r ecord. One i s f orced t o wonder what was the i mpact o n the s cribes o f Mesopotamia o f t he i ntroduction o f papyrus i n c ontrast t o t he c lay o r s tone tablet.

THE COST OF COLLECTION The application o f the micro-computer t o the management o f a rchaeological d atabases c an b e h ighly c ost a nd r esearch effective. Although one i s a lways impressed by the ability o f c omputerised s ystems t o a ccess, a nalyse a nd d isplay data, the most expensive a spect o f most systems i s not the c ost o f h ardware o r s oftware but t hat o f data e ntry. The a rchaeologist's d esire f or a primary paper a rchive coupled w ith t he g eneral i nability o f t he c omputer i ndustry t o p romote r emote c ollection d evices has l ed t o a position where v irtually a ll a rchaeological databases a re based upon p ro-forma r ecord sheets t hat a re hand-written i n the f ield a nd s ubsequently t ranscribed o nto c omputer, o ften a t a t ime a nd p lace quite r emote f rom the s ite or source of t he data. This method o f data c ollection, t hough p roviding a c urious s ense o f s ecurity i n the f orm o f huge s tacks o f f requently muddy f orms, i s n ot c ost-effective s ince not o nly does a ll data, i n effect, have t o b e r ecorded twice, but i t must a lso b e c hecked b oth b efore a nd a fter data entry i f t he r esultant database i s t o have any value f or analysis. Over t he l ast f our y ears a variety o f small h and-held c omputers h ave b een r eleased onto t he market providing a f acility f or t he collection o f data d irectly i n the f ield, l iterally i n t he t rench. D espite t remendous advances i n micro-computer t echnology t hese d evices t end t o b e v iewed a s oversized c alculators a s opposed t o ' real computers' Work a t H eslerton over t he past t hree y ears h as d emonstrated t hat the u se o f hand-held computers a s r emote d ata c ollection d evices i s not o nly v iable but a lso d esirable i f t he c ost o f database c reation i s t o b e h elp within a cceptable l imits. .

Although much

i s

made

i n

2 3

the

advertising

l iterature

of

the l arge memories of currently available micro-computers, 2 56k b eing s tandard o n 1 6-bit machines, t his i s i nsignific ant by comparison with mainframe computers which c an access huge memories. S ince a lmost a ll i mplementations o f BASIC, Pascal and the majority o f l anguages available o n m icro-computers c an access no more t han 6 4k o f data a t a ny one t ime this l imited a rea, equivalent to about 2 5 pages o f t ext, s hould b e u sed w ith c are i f the s ystem i s t o r un efficiently; o n hand-held d evices with capacities o f up t o 2 4k, i nclusive o f p rogram a rea, t he n eed f or h ighly s tructu red data s torage i s even more important. The system d evised a t H eslerton was d eveloped i n r esponse t o the r ealisati on t hat much o f the potential o f a mainframe database, d esigned i n a ssociation w ith North Yorkshire County Counc il, was l ost o n account of the duplication of effort i n t he data c ollection p rocess ( Powlesland 1 983). By comparison with the most c ommon applications o f m icro-computers, word p rocessing a nd f inancial management, the problems presented by the construction o f archaeologic al databases a re i mmense. The w ide r ange a nd l arge quanti ties o f data b eing collected mean t hat f or any database t o b e o f value i t must o ffer r elational f acilities p roviding access t o a l arge number of d ifferent data f iles a t a ny o ne t ime; by v irtue o f this n eed i t i s e ssential t hat d ata b e s tored i n the most efficient manner possible, a n a spect emphasised when u sing t he h and-held d evices.

DATA STRUCTURES:

THE

POTENTIAL

I f o ne i s t o u se t he c omputer merely a s a n e lectronic f iling c abinet then t here a re f ew c onstraints upon h ow a database s hould b e c onstructed; moreover i f this i s t he p rimary a im then a paper based s ystem would probably b e more e fficient. Although n ew computers a re r eleased o n t he market a lmost daily the d ifferences b etween o ne s ystem a nd a nother a re l argely c osmetic w ith f ewer t han s ix CPU's, t he Central P rocessing Unit t hat does the majority o f the work, b eing i n g eneral u se. Wide d ifferences i n p erformance c an b e d emonstrated but the t rue power o f a ny micro-computer i s o nly h arnessed t hrough t he u se o f p owerful s oftware. Although p rocessing speed i s f requently quoted a s a n i ndicator o f c omputer p ower, which i ndeed i t i s, t his i s o f considerably l ess i mportance than t he ability t o access data o n a w ide r ange o f d ifferent a ttributes f rom d ifferent r ecords, especially g iven the s peed of access u sing a n a lternative s ystem t he paper r ecord. The ability o f a ny computer program t o provide r apid a ccess a nd analysis i s ultimately d ictated by t he r ecord s ize a nd s tructure -

employed. I n

t he

past,

a nd

i n

many

databases such a s Cardbox, r ecords u sing variable l ength s equential which w ill b e f amiliar t o anyone c omputer w ith a c assette machine.

2 4

c urrent

g eneral

p urpose

h ave b een s tored o n d isk f iles, a r ecord f ormat who has u sed a homeT his f ormat i s g rossly

i nefficient f or a nalysis a nd quick a ccess. S equential access systems r unning o n micro-computers suffer o n a ccount o f the f act t hat every t ime data i s a ccessed the whole data f ile must b e r ead until the d esired r ecord i s l ocated whether t he f ile i s i ndexed o r not: moreover when data i s edited t he complete f ile then has t o b e r esaved. I n a rchaeology, where t he f acility f or e ntering f ree t ext i s r evered, this data s tructure has b een widely u tilised s ince i t p rovides t he most obvious r oute t o e fficient d isk s torage. S equential f iles a re, however, more susceptible t o c orruption a nd can l ead to excessive d isk w ear. Quick access can only b e a ssured i n v ery l arge databases with the u se o f f ixed l ength r andom access r ecords where r ecords a re r ecalled o n the basis o f a n i ndex s uch that a ny i ndividual r ecord c an b e d irectly accessed. Unfortunately t he s heer quantity and range o f data collected by the f ield a rchaeol ogist a nd a ssociated specialists i s s uch t hat a r eliance upon the u se o f t ext f ields means t hat r ecords will b e v ery l arge unless some d egree o f c oding i s i ntroduced. Recording s ystems based o n the extensive u se o f c odes g enerate a s urprising d egree o f r esistance, e specially c onsidering t hat many databases operate o n the basis of ' keywords' which i n themselves r epresent a r ather c umbersome f orm o f c oding; why r ecord a ' post-hole f ill' i n t ext which takes up 1 4 and i n many cases 1 6 bytes o f memory when a c ode c an b e stored i n a s ingle byte? I f we a re t o u tilise the f ull potential o f the excellent h ardware available t hen we must u se the data compression and i nterpretation facilities that t hese

machines

o ffer.

DATA COMPRESSION Although c omputers p rovide t he f acility f or p rocessing character data, a ll p rocessing i s based o n the movement and manipulation o f numbers. The s implest m ethod o f data c ompression i s t o use abbreviated t erms a s d iscussed by F lude ( 1984). More elaborate s ystems f or t ext c ompression which u se the unprintable codes i n the A SCII t able t o r epresent f requent words have b een d iscussed by L ewis, b ut i n this case the methods a re more appropriate t o t ext f iles r ather t han data ( Lewis 1 984, 1 985). Two m ethods p rovide h igh l evels o f c ompression o f c oded data. F irstly, u tilisi ng Boolean mathematics to operate o n the i ndividual b its which combine t o f orm each number, a nd s econdly, by s torage o f numbers a s s ingle bytes o r two byte words. A b yte, equivalent t o a s ingle character o f s torage, comprises e ight b its which a re s et a s either 0 o r 1 p roviding a numeric range f or a s ingle byte b etween 0 a nd 2 55; a two byte word c omprising a 1 6-bit number c an, i n t urn, s tore a ny number b etween -32767 and + 32767. By u sing the Boolean l ogical operators A ND, OR, NOT, a ccess c an b e easily g ained t o each b it s o t hat a number ( 8 i n a s ingle byte, 1 6 i n a 2 -byte word) of t rue/false s tatements may b e s aved u sing

2 5

TABLE 1 Binary Number

Decimal Number

0 000000000000001 1 000000000000001 0 000000000011001 1 000000000011001 0 001010010010011 1 001010010010011

1 -1 2 5 -25 5 267 -5267

= = = = = =

The most s ignificant, o r f irst b it i ndicates whether the number i s positive o r negative, the l east s ignificant, o r l ast b it i ndicates whether o r not i t i s o dd ( 1) o r even ( 0). Reading f rom r ight to l eft, b its 2 to 1 5 have v alues d etermined o n t he basis o f 2 t o the p ower o f p osition m inus 1 ( 2-( position 1)). Thus bit 2 has a value of 2 , b it 3 has a value o f 4 a nd s o o n. The b it v alues c an b e equated with y es o r no a nswers. The b inary operators compare the bit pattern o f each n umber, a nd a ny number c reated by adding a s equence o f b it values c an b e d isassembled by u sing t he operator AND w ith the absolute b it v alues, f or example: 2 5=1+0+0+8+16 1

AND

2 5

=

1

AND

0 000 0 0000 0 000001 0 000000000011001

AND

4 AND 2 5 = 0 0 000000000000100 0 000000000011001

• The s et

r esult t o s o

( bit

1

( bit not

3 w ith u sed

o f the AND operation t hat B AND 2 5 = 8.

=

1 i n

i ndicates

both

n umbers)

a value o f t o make

which

b its

4 i s 2 5)

a re

This f acility i s o f particular v alue when d ealing with c hecklists a s part o f a r ecord. P owerful t hough i t i s, i ts value, when applied t o the archaeological r ecord, i s l imited s ince s imple y es/no a nswers a re r arely appropriate. I n contrast, c haracter compression u sing the A SC$ a nd CHR$ functions i n BASIC i s i mmensely powerful, c overing a vast numeric range. Experience a t Heslerton has s hown t hat a s ingle byte i s quite sufficient f or t he s torage o f a ny c oded f ield, and despite the c oding o f most f ields i n a ll r ecords, u sers o f t he s ystem h ave quickly f amiliarised themselves with t he code l ists. The u se o f these t echniques o n t he h and-held c omputers, i nitially w ith a c apacity of l Ok ( 24 Context Records) and now expanded t o 2 4k, has made i t possible t o s tore more t han a d ay's w orth o f r ecords ( 50 Context Records or 2 00 Small F inds Records) w ithout t he n eed t o dump t hem t o a l arger d evice. The u se o f these methods o f course c onsiderably i ncrease the

2 6

data compression p rocessing t ime

d oes o f r equired

to d isplay any r ecord, t hough this i s o nly noticeable i n t he hand-held machines which u se battery power and r elative ly s low p rocessors. The hand-held d evices c ould not b e u sefully u sed f or analysis o f a ny but the smallest data s ets but s hould b e v iewed more a s a f orm o f electronic notebook. The b enefits o f data compression once d ata i s t ransferred o nto a c onventional d esktop m icro-computer f ar outweigh any r eduction i n speed c aused by the n eed for t ranslation o f c odes s imply by p roviding a ccess t o t he maximum number o f r ecords a t any one t ime. By combining c haracter c ompressed c odes i nto f ixed l ength r ecords, s earch and sort r outines can b e maximised s ince they n eed o nly operate o n a small number o f bytes a t a ny o ne t ime. Given the 6 4k l imitation imposed on the data a rea under most l anguages t he u se o f this t ype o f c ompression a llows whole i ndexes t o b e h eld i n comparatively small memory a reas, a f eature which c an d ramatically r educe t he c omplexi ty o f sorting r outines ( Knuth 1 973). A rchaeological

data

i s

i n

f act

i deally

s uited

f or

c odification and s ince the u se o f codes i s only n ecessary a s part o f data entry o r editing, this m ethod o f data handling i s h ighly desirable. Once the data has b een s aved t he c odes b ecome t ransparent t o the u ser s ince t hey merely p rovide i ndicators which a re i nterpreted i nto English when r ecords a re r ecalled t o t he s creen o r p rinter. S ince t he c ode l ist u sed i n the t ranslation o f the r ecord i s d efined by t he u ser, considerable f lexibilty i s i ntroduced o ffering the facility, f or i nstance, o f generating r ecords i n a f oreign l anguage. At H eslerton over 1 0,000 r ecords h ave b een p rocessed u sing the hand-held computers which provided i n e ffect a s eries o f c heap t erminals a llowing s imultaneous data entry by a number o f p eople a t the s ame t ime; the task c ould n ot have b een c ompleted w ithout the m ethods d iscussed. A lthough a b road r ange o f data c an b e r eadily c oded, the Context Record i n particular r equires some space f or t he entry o f f ree t ext notes. However, t his n eed not b e a l arge a rea s ince the majority o f r ecords r equire only l imited n otes e specially s ince most o f t he c ontext's a ttributes have already b een i ncorporated i n c oded f ields. The r ecord s tructure f or data c ollected u sing t he h and-held computers was d esigned t o c over the basic data r equired i n a ll cases p lus a s hort 1 50 c haracter a rea f or notes; t his has p roved sufficient f or more than 9 5% o f a ll the r ecords p rocessed. Where additional data i s r equired, t his i s b est handled by additional r ecords which a re accessed a s continuation r ecords. By u sing t his m ethod t he data s torage a rea r equired c an b e k ept t o a n absolute minimum, a v ariety o f d ifferent d emands, whether t hey b e f or extensive f ree t ext o r f or r ecord

additional stratigraphic data. I n t his numbers a re v ery small, s equential f iles

e fficiently.

2 7

c ase, where c an b e u sed

DATABASE STRUCTURE Whilst t he s tructure o f the i ndividual r ecords i n a database d etermines both the speed and f lexibility o f a ccess, t he a nalytical a nd s tatistical potential i s d etermined by the r elational facility t o access a nd c ross-reference a s election o f data f iles a t a ny one t ime. Over t he l ast two y ears a number o f r elational databases have b ecome available f or u se o n micro-computers r anging i n p rice f rom £100 t o £30,000, but i n many c ases these universal d atabase p rograms s hould b e v iewed w ith c aution. DBase I I ( shortly t o b e superceded by a f ar superior dBase I II) i s the most w idely u sed by a rchaeologists i n Britain; h owever, s ince i t c an o nly access two f iles a t a ny one t ime and s upports only 3 2 f ields p er r ecord i ts potential i s l imited t o small databases. I ts t rue potential should p erhaps b e s een a s a n adjunct t o a more s ophisticated s ystem. At t he t ime when the hand-held computer was i ntroduced i nto the r ecording s ystem a t H eslerton t here was no available s ingle d atabase package t hat would carry out the multiple tasks r equired; t his i s s till the c ase. Besides the f acility t o work o n a combination of different data f iles Contexts, Objects, F inds, I llustration Records, etc. f acilities w ere n eeded f or the t ransfer of p rograms and d ata f rom the hand-held machines a nd f or t he g eneration of g raphics d irectly f rom the r ecord. Those p rograms that might have g iven the c ombined f acilities r equired g enerally u tilised d isk s pace i nefficiently and thus the only solution was t o write the n ecessary software i n available s pare t ime over a l ong p eriod. The r esulting programs were f irst u sed f or p rocessi ng t he paper r ecord g enerated over a s ix y ear excavation a t Heslerton S ites 1 and 2 , a nd have s ince b een u sed over t he l ast y ear i n t he f ield b oth i n H eslerton a nd by t he St. Patricks I sle Archaeological Trust o n the I sle o f Man, who bought t he h and-held s oftware a nd p art o f t he m icrocomputer software during i ts development. I n o rder f or any r elational database t o f unction s uccessfully i t i s n ecessa ry t o l ink the r ecords through a p rimary k ey o r i ndex f ield; i n t erms o f excavation data t he S ite, A rea a nd Context Number combine t o provide t his k ey f ield which i s i ncluded i n a ll r ecords. By u sing t his p rimary k ey a s a r ecord f inder i t i s then possible t o access data o n the basis o f a ny f ield o r c ombination o f f ields f rom a combination of r ecords. Besides the n eed t o a ccess data t he database must o ffer t he f acility t o output data i n a number of f orms b esides s tandard p rinted r ecords, c atalogu es a nd i ndexes. I t i s i mportant t hat d ata c an b e d umped t o d isk a s t ext f iles t hat c an then b e accessed f rom a word p rocessor a nd t hat d isk f iles c an b e g enerated i n s uch a way t hat they may b e accessed by other databases. The most easily a ccessed f ile t ype i s t he Common S eparated Value ( CSV) f ile i n which all data i s written t o d isk enclosed i n quotes a nd s eparated by c ommas. Using t his data s tructure data c an b e quickly t ransferred t o a p rogram s uch a s d Base I I o r t o s preadsheet p rograms s uch a s SuperCalc2 which provides a n i deal environment f or the g eneration o f t ables. Most i mportantly t he u se o f C SV f iles m eans t hat t he -

-

2 8

excavator c an p rovide specialists w ith a n abstract o f data o n a d isk which c an b e easily accessed, a f acility which, p rovided t he d isk f ormat i s s uitable, s hould i ncrease t he i nterchange o f r aw data a nd t hereby d ramatically r educe basic specialist r esearch t ime. Data i n t he H eslerton database c an b e output o n d isks u sing a range o f f ormats, t he a rchive i ncludes o ne s et o f r ecords a s t ext f iles i n I BM disk f ormat u nder MSDOS, the current i ndustry s tandard f or 1 6 bit m icro-computers.

HARDWARE AND

SOFTWARE

Getting t he r ight c ombination o f hardware a nd s oftware i n a n a rea where g reat c laims a re made about a ll machines s eems a t f irst t he most daunting t ask; i t i s h owever s oftware which s hould b e the p rimary controlling factor i n t he c hoice o f h ardware. I f the r equired s oftware i s t o b e written i n house t hen any hardware that w ill d o the j ob can b e s elected. H owever t he c ost i n man-hours o f w riting effective and durable s oftware i s a stronomical, a nd i t s eems p ointless t o r einvent the wheel. Although t he r ange o f hand-held d evices i s now f ar greater than three y ears a go, t he Sharp P C1500A r emains t he most s uitable machine f or u se i n the f ield; a possible alternative, the S harp P C1350, may i n t ime r eplace t he P C1500A but t his machine, which u ses r emovable 1 6k RAMCARDS, has y et t o b e p roven i n t he f ield. Larger machines c ommonly c alled ' lap-held computers' such a s the Epson HX20 a nd P X8, whilst i deally s uited f or u se i n g eophysics o r i n the s ite hut, a re s till t oo l arge, exposed and expensive f or u se i n the t rench. All the hardware c urrently i n u se a t H eslerton i s manufactu red by Sharp. Each d evice offers something not g enerally avalable i n o ther p roducts. A Sharp P C5000 l ap-held machine offers the f ull power o f a d esktop machine i n a s ingle battery p owered u nit t hat not o nly i ncludes a p rinte r but also u ses bübble memory cartridges which, though expensive, a re v ery durable a nd c ontinue t o f unction w ithout r isk of data l oss i n the dusty environment o f a s ite hut. Once back a t t he excavation h eadquarters, d ata i s t ransferred t o s tandard I BM f ormat f loppy d isks a nd a lso passed t o a l arger machine where r ecords a re s tored o n a 1 0 megabyte hard d isk. A s data i s t ransferred t o f loppy d isk t wo c opies a re automatically g enerated w hich a re k ept a s backups. The d esktop machine currently i n u se i s a S harp M Z5600 w ith 5 12k o f RAM, 1 0 megabyte h ard-disk, t wo m inif loppy d isk ( capacity 6 40k each) d rives, a nd eight c olour g raphics f acilities. Under Sharp BASIC t he u ser h as a ccess t o 3 80k o f memory, a f eature not available o n a ny o ther machine, which a lso i ncludes f acilities f or i nteractive g raphics u sing a ' mouse' a nd a n umber o f t ext a nd g raphics w indows. An i ncidential advantage o f u sing a s ingle manufacturer's p roducts i s i n a lways b een outstanding. The upgraded t hrough t ranslation i ncrease t he i t possible

speed o f t o run

t erms o f support, which has s oftware i s g radually b eing i nto P roPascal which w ill

operation a t t he i t o n a greater

2 9

s ame t ime range o f

a s making machines.

Although hardware f eature

much o f the software w ill not run o n more l imited t he i nteractive g raphics, which a re a major o f the system, c annot n ecessarily b e s upported.

The u se o f f aster l anguages s uch a s P ascal a nd C offers a considerable speed advantage over BASIC; h owever, t he f acility f or i ndividual u sers t o tailor s oftware t o their n eeds i s then l ost. To those who e njoy p rogramming t he availability o f packages which c an b e t ailored t o t heir own n eeds may s eem i nteresting, but a t the s ame t ime i t i mplies t hat t he s oftware h as f ailings which t he u ser may w ish t o r ectify. The s ingle d istinguishing f actor i n good s oftware i s t hat i t s hould r un s uccessfully w ithout the u ser having any knowledge o f computing a t a ll; i t s hould not n eed t o b e a ltered. F or t hose c ontemplating writing a ny software i t must b e a ccepted t hat u ntil a p rogram i s c ompletely durable o r i diot-proof i t i s not complete; we cannot a fford t o r ely o n the presence o f a p rogrammer i n o rder t o u se our databases. I t i s a lways t empting t o g et o n with the next j ob o nce a p rogram i s s een t o r un, e specially s ince i diot-proofing t akes a s much a s t en t imes a s l ong a s writing the p rogram i tself. We h ave a ll s een o r even g iven d emonstrations o f s oftware u nder d evelopment which have not f or some i rritating r eason done t he expected; i t i s not o nly embarrassing but f rightening considering the once-only nature o f the a rchaeological evidence we a re handling.

POST-EXCAVATION

SAVINGS

Although t he u se of o n-site c omputers f or c ollection a nd p rimary analysis of data c an improve b oth t he quality a nd u niformity o f the r ecord t he advantages o f d irect e ntry a re not f ully r ealised until t he post-excavation s tage. Tom Hassal h as r ecently estimated t hat t he r elative expenditure o f t ime o f a n excavation d irector i s about 1 :3 i n r elation t o excavation a nd post-excavation ( Hassal 1 984). This r atio can b e d ramatically c hanged by the application o f a d irect e ntry s ystem s ince a t t he e nd o f t he day t he g reater part o f post-excavation t ime i s spent o n compiling a nd i ndexing t he paper a rchive. A rchive p reparation t ime c an b e r educed t o l ess t han a half with a d irect entry s ystem, whilst i ndexing a nd c ross r eferencing c an b e f ully automated. T he ' Cunliffe Report' o n publication ( CBA/DOE working party, 1 982) r epresents a r esponse not o nly t o t he appallingly l ow r ecord o f published excavations but a lso t o the t ime a nd energy u sed i n g enerating r eports. T he i nvestment o f l arge r esources a t a post-excavation s tage h as b een n ecessary b ecause o f t he appalling data management p roblems g enerated b y l arge paper a rchives f requently c reated against a backg round o f v ery l imited r esources. By u tilising a d irect entry system the post-excavation p rocess c an b e r adically a ltered. Basic s tatistical a nd s patial a nalysis, which cannot b e cost j ustified u sing a paper based archive, c an now a nd s hould b e p erformed a s a matter o f c ourse i n a f ew minutes d irectly f rom the a rchive c ompiled o n t he s ite.

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D A T P R O C E S I N G A T H E S L E R T O

F igure

When i ntegrated with word processing f acilities the t ime and c onsequent f inancial s avings a re s uch t hat t hough postexcavation t ime may b e r educed t o about a half o f that conventionally r equired t he end p roduct c an i nclude a range of data and p rimary analysis not p reviously possible. At H eslerton t he post-excavation a nd publication ( including the majority of the a rchive i n microfiche) o f a t en acre multi-period s ite w ithin a two y ear p eriod h as o nly b een possible o n account o f the extensive u se o f a range o f m icro-computers a nd a variety of i ntegrated p rograms maximi sing the u se of the d ifferent hardware.

SUMMARY A w ide range of computer hardware a nd s oftware i s currently available which c an b e u sed t o e nhance t he management a nd c reation o f excavation databases. By u sing d irect entry s ystems f or data c ollection o n s ite t he u niformity a nd quality of the r ecord c an b e i ncreased whilst the c ost o f database c reation c an b e k ept t o a m inimum. I f a ny c omputer system i s t o b e o f value i s must b e designed w ith t he end p roduct a rchives a nd r eports i n m ind. I n o rder t o maximise the use of d isk storage, s earch a nd a nalysis t imes u sing micro-computers s ome d egree o f c oding must b e e nvisaged which, combined w ith random a ccess f ixed l ength data f iles, p rovides t he most f lexible e nvironment f or output and analysis. I n o rder t hat t he potential o f machine-based systems c an b e f ully r ealised s oftware s hould b e c onfigured to produce a wide range o f output f iles t hat c an easily b e u sed w ith other p rograms s uch that s pecialist a nd r esearchers can quickly gain access t o all r elevant data. The d evelopment a nd s ubsequent u se, b oth i n t he f ield a nd during post-excavation, o f a d irect c ollection system a t Heslerton, North Yorkshire, has r evealed t hat, excluding the cost o f software d evelopment, which was b orne b y the author, t he overall c ost o f t he s ystem, ( c. £ 5000) would easily b e s aved during t he post-excavation s tage o f a ny l arge p roject ( see a lso P owlesland f orthcoming). -

-

REFERENCES C BA/DOE working p arty, 1 982. The publication o f a rchaeological excavations. Council f or British Archaeology. F lude,K. s ystem -

1 984. " Setting u p a n a rchaeological computer a n i ntroduction" i n Martlew,R. ( ed.) 1 984, 3 1-44.

Hassal,T. 1 984. "Publication: c risis Martlew, R . ( ed.), 1 984, 1 42-57. Knuth,D. 1 973. Massachusetts.

Fundamental

a nd

Algorithms.

3 2

i naction"

Reading,

i n

Lewis,M. 1 984. Computing June

"A quart i n a p int 1 984, Vol. 7 No. 6 ,

1 985. "More i nto Vol. 8 No. 4 , 4 3-4. -

l ess",

pot", 4 7-8.

P ractical

P ractical

Computing,

April

1 985,

Martlew,R. ( ed.) 1 984. I nformation Systems i n Archaeology. New Standard Archaeology, Alan Sutton, Gloucester. Powlesland,D. 1 983. "Pots, pits Computing, Vol. 6 , No. 6 , 1 44-6. f orthcoming. papers. -

"A computer

i n

3 3

and

the

portables",

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P ractical

I FA Technical

A NEW DIRECTION OR A NEW DISTRACTION: A PRAGMATIC ASSESSMENT OF COMPUTER APPLICATIONS IN ARCHAEOLOGY BASED ON WORK AT DANEBURY HILLFORT Gary Lock "If we can see the present clearly enough, we shall ask the right questions of the past" (Berger 1972, 16). There is increasing debate in certain areas of archaeology concerning the use of computers; are they beneficial at all, and if so in what ways, or are they expensive "white elephants" detracting from the business of "real" archaeo­ logy? The answer, of course, will depend to a great extent oo the individual's philosophical outlook and methodolog­ ical approach to the subject. Even so, it is possible to generalise about archaeological attitudes towards computers and to identify different levels of belief. This paper is offered from a position within the centre of the range, it incorporates a cynicism which predicts that computers can cause as many problems as they solve and at the same time acknowledges their potential. Such a position seems to be a lot healthier for archaeology than the two extremes; on the one hand those who dismiss computers completely, and on the other, those whose interest in the technology is so over­ powering that they become distanced from the original archaeological questions. The main problem is in identify­ ing suitable applications before they are attempted; the present paper is meant as a step towards this aim. The views expressed here are necessarily pragmatic as they result from involvement in the computerisation of the 17 seasons of excavation at Danebury hillfort. The ideals of theor have been reshaped by the re��ities of practice. Despite this, Danebury-stands out as one of the very few large-scale British excavations to reach publication where computing has formed an integral part at all levels from data collection, through routine information retrieval to multivariate statistical analyses. The rollowfng discussion fallsi n to two areas, the first describing aspects of computing which can be called 'new distractions'. The second part is more descriptive and concentrates on work at Danebury hillfort which has actually achieved results, indicating possible 'new directions', (see Cunliffe 1984, Lock 1984). When and why the initial decision is made to use a computer can drastically affect the outcome of the exer­ cise. The Danebury experience has shown that to �aximise efficiency and economy, computerisation must be an integral part of the original research design witp its own adequate budgeting. If it is included as some kind of 'interesting extra' or even as a well-intentioned afterthought serious problems can result. Problems can also arise because of the 'co�puting environment' within which the work is carried out. This involves a complex network of pressures including 35

whether the wor_ker is · solate.d or part of a team and whether mainframe, mini or microcomputer facilities are available. It must be unequivocally stated here that the present writer is totally in favour of using mainframes when available. Admittedly, for the user, they can appear to be remote and inaccessible, but experience has shown that the advantages gained by their use can heavily out­ weigh these initial impressions. Mainframes are much more capable of accommodating the large amounts of complex data that archaeology routinely generates. They also have numer­ ous packages which can not only store the data via a Data Base Management System (DBMS) if so desired, but will also analyse them and present the results in various ways. Their analytical capabilities need to be emphasised as a growing number of recent reports on computer applications in archaeology have been concerned with data capture and stor­ age. This trend is reflected by the changing content of papers presented at the annual Computer Applications in Archaeology conference (CAA), the only regular national forum. In 1981 only one of the 18 papers was directly concerned with databases as opposed to eight out of the 23 papers given in 1984. This increasing obsession with the particulars of data collection and storage is worrying because commercial packages exist that will do the job, albeit not·. perfectly but at least as well, if_ not better, than the programs that most archaeologists are currently capable of writing. The commonly used micro-base package dBaseII is an example of a commercial DBMS that will collect and store data as well as perform basic information retrieval exercises. Admittedly it has shortcomings, the theoretical limitation of 65,536 records, for example, appears off-putting to some archaeologists. Nevertheless, with a little ingenuity these constraints can be overcome, records can be sub-divided, for instance, or several files used to increase capacity. It is just not worthwhile for the average programming archaeologist to try writing a substitute. This phenomenon of massive duplication of effort in data-capture existed before computers, with some archaeo­ logists seeming to have a _psychological barrier _A_gainst using another's recording system. With the increasing availability of micro computers, however, the duplication has become exaggerated by the increased time and effort needed to write a complex DBMS. The writing of the program can become more important than its eventual use to archaeo­ logy. Surely as archaeologists we should be concentrating equally, if not more, on what to do with the data once we have it on a machine. Referring again to the 1984 CAA conference, only two of the 23 papers give a straight­ forward account of an analysis with archaeological results. Interestingly these are both on mainframes illustrating their analytical capabilities not only through the use of packages but also because of their power and speed. This power includes a choice of high-level programming languages and usually a team of professional applications and systems programmers who, along with installation specific document36

ation, increase the probability of obtaining worthwhile results. An example of a data-capture procedure which high­ lights some of the advantages of mainframes has been recently reported by Stallard and Gray (1984). Here an intelligent 'front end' for a commercial mainframe database package was written to collect and validate conservation data from the archaeological laboratory at Cardiff University. Significantly, it was written by the Univers­ ity's computing staff in response to an archaeological problem. It mus! be appreciated, however, that computing staff are not going to be fully aware of archaeological needs and problems, and that close liaison is necessary.

-

This is not to suggest that microcomputers do not have any place within archaeology. Voorrips has recently argued (1984, 49) that their greatest potential future uses are probably as intelligent terminals for mainframes and as dedicated machines. T.hese will include the areas of data collection and validation with eventual transfer to a main­ frame for analysis as well as operations such as inter­ active graphics and word processing. This latter area has already proved to be of considerable importance within an archaeological environment, probably due to the amount of text archaeologists produce, the size of most publication backlogs and the inherent advantages of word processing. It is, however, very expensive in machine-time often resulting in drastic under-achievement, well below the potential of the computer being employed. Less expensive machines dedi­ cated to word processing are already available which should release powerful microcomputers for more suitable tasks. As stated earlier, the 'computing environment' can seriously influence the results of a computer application. Here we can identify a major problem area specific to microcomputers; the 'resident expert syndrome'. For various reasons including non-availability of mainframes, finances and peer group pressures, many archaeological teams, from university departments to units, purchase a microcomputer. It is a familiar pattern that no one within the team has any knowledge of computing but eventually one person is curious enough to use the machine or else is delegated to do so. Once that person has gained a basic familiarity with the machine the 'resident expert' is born who then becomes the focal point for any discussion or projects involving the computer. In this context 'basic familiarity' is used in its widest possible sense; personal experience has shown it to range from switching the computer on to attending an induction course. There are fundamental philosophical prob­ lems involved in our reliance on 'experts' and how a blink­ ered belief in them can limit the progression of knowledge (Feyerabend 1978). This is becoming more disturbing with the introduction of so-called 'expert systems' and archaeo­ logists should seriously assess whether they will benefit from such intellectual straitjackets (see Huggett, this volume). In the present context the 'resident expert' is likely 37

t o l ead to the c ompounding a nd p roliferation o f f actory microcomputer t echniques. The author Voorrips r ecent v iew that a ny a rchaeologist i nvolved with micros may d evelop i nto:

u nsatissupports who g ets

h is own bad s ystems a nalyst, h is own bad p rogrammer a nd h is own b ad operator. I n the end h e probably p roduces bad a rchaeology a s w ell ( 1984, 4 8). The point to b e emphasised h ere i s t hat u sing a computer s eriously, a nd especially a microcomputer, i ntroduces t he n eed t o appreciate the d iscipline o f c omputer s cience. The existing g eneral l ack o f understanding surrounding the u se o f computers i s supported by the h ierarchical structure o f British a rchaeology, where i t i s easy f or t he p eople a t the top t o l ose t ouch with what i s happening a t the everyday g rass-roots l evel. I t i s, however, these p eople who o ften possess t he power t o i nfluence the r esources o f a rchaeol ogy, who must b ecome aware o f the c omplexities i nvolved i n computing. I t i s t o b e hoped t his w ill then l ead t o t he acknowledgment that t o b e s uccessful i n this a rea s uitably t rained s taff must b e employed a nd t he p resent ' resident expert s yndrome' s hould b e d iscouraged. A n i nteresting example o f h ow someone i n a n elevated position within the a rchaeological h ierarchy can i ncorrectly p erceive work a t grass r oots l evel i s shown i n a r ecent paper by Cleere ( 1984). I n this h e o ffers a n a ssessment o f r ecent t echnol ogical d evelopments w ithin the f ramework of the overall n eeds o f modern a rchaeology. Two p rinciple examples a re c ited t o show where computer a nalysis has b enefited excavation data: Barry Cunliffe's work i n a nalysing t he thousands o f p its a nd post holes a t Danebury has b een f acilitated and enriched by computer a nalysis, a nd i t c annot b e c laimed that the p rocessing t ime was extended, s ince most of the examination a nd r ecording o f these f eatures was c arried out i n t he f ield during t he course of the excavation p roper a nd not during the p ost-excavation p eriod. Work by the C entral Excavati on Unit, at Winklebury f or example, has s imilarly d emonstrated t he worth o f c omputer handling o f s uch data ( d eere 1 984, 1 5). . .

.

The r eference t o Danebury i mplies t hat the c omputerisation has b een somehow absorbed i nto the mechanics o f r unning t he s ite w ithout a ny extra r esources o r f acilities b eing n eeded. This i s a dangerous misconception a s no c omputing i s i n f act done o n s ite a t Danebury; i t i s a ll c arried o ut a t the post-excavation s tage a nd has occupied one f ull-time worker f or s ix y ears, i nvolving a dvanced h igh-level p rogramming a nd the extensive u se o f mainframe p ackages. The r eference t o W inklebury i s equally m isleading a s t he work there actually n egates the i dea o f computer s tandardi sation a nd data-exchange which i s o ne o f the main t hemes of the c ited paper. which the W inklebury

The Honeywell Mark data w ere p rocessed

3 8

I II mainframe i s no l onger

u pon u sed

by the Central Excavation Unit and the pottery data alone have been transferred to a microcomputer making them avail­ able only on 8 inch IBM format disks. The remaining data, consisting of site plans, sections, context records and object summaries, are available on microfiche (DoE pers. comm. and Smith, 1977). The Winkle6ury case illustrates some of the problems to be encountered when computerised data-c�mpatibility is attempted and the im_g__ortance of hard­ ware enhancement and updating in the world of rapidly advancing technology. No personal criticism is intended here'""; but rather the aim is to illustrate how people in positions of influence, for example unit managers and site directors, often encourage computing in archaeology but can be labouring under damaging misapprehensions. The situation is further complicated because responsi­ bility for computing is often delegated to those further down the hierarchy. Enter the 'resident expert' once more who, having been elevated to this slightly prestigious position, may decide it is worth nurturing further by maintaining the mystique of the machine. This is not meant to sound covertly sinister and,indeed, we are all probably guilty of similar actions in one way or another. The motive could be to retain employment under conditions of ever increasing financial cuts, or a genuine interest in comput­ ing. It is well known that computing can become addictive; the Science and Engineering Research Council, for example, has stated that distraction from the main line of enquiry due to getting hooked on computing, is one of the major reasons for unfinished research projects "largely because of the sheer pleasure to be had from manipulating the computer" To be able to assess realistic goals for a computer application in archaeology it is necessary to be aware of ·machine limitation�. These are not only the limitations ·peculiar to the syste� to be used but also the more general theoretical limitations. The latter will affect every level of operations from the initial structuring of the data-set to multivariate statistical techniques. These will be dealt with here in the logical operational sequence starting with data collection and the structuring of the data-set. In an ideal world an archaeologist would be able to 1) capture all possible data and 2) declare all future analys­ es at the start of an excavation with both of these points controlling the structuring of the data-set. Indeed, it is a belief in these abilities that underlies the unattainable dream of an automated recording system to suit all sites. In reality both of these points appear dubious when exam­ ined more closely. Data exists as a physical continuum in the ground; from its initial recording on an excavation we are dealing with interpreted information which represents the actual data. This is a product of the mind with all the associated social and cultural conditioning and as such it can not be objective. If we accept this inherent subjectiv­ ity of data it is easy to see the dangers in the popular 39

misconception that computerisation somehow makes data more objective. Neat columns of figures on a computer printout can convey a misleading pseudo-objectivity. The data is no more objective than when initially recorded on the excavat­ ion, problems associated with its interpretation and the decision-making involved in its collection can become camouflaged by the process of computerisation. Having said that, it is undeniable that computerisation forces the archaeologist to think more logically about the structure and codification of the data. The second point mentioned was that all future analyses should be definable at the start of an excavation. The Danebury experience has shown that this is very unlike­ ly as many analyses are deductively generated as work progresses. In fact Danebury has shown that it is more likely for two data-sets to be needed to cater for what can be termed primary and secondary investigations. Primary investigations are concerned with the basic descriptive analysis of the site, which at Danebury fills most of the first two volumes of the published report (Cunliffe 1984). From the computing viewpoint the primary investigations consist of the retrieval of information used to produce the numerous counts and low-level statistics necessary for a basic excavation report. Computerisation at Danebury is essential because the data-set is large, occupying approx­ imately 17 megabytes of computer storage at present. The computerised data-set consists of over 150,000 pottery sherds, a similar number of animal bone fragments and numerous other find-types from nearly 1,500 rock-cut pits across the interior of the fort and from the stratified areas in the quarry hollows. Primary investigations control and structure the initial data-set. Secondary investigat­ ions are concerned with middle and high range questions and involve the use of specialised working data files which are either sub-sets of the primary data-set or constructed from various parts of it. Primary and secondary interests may progress in parallel although the former are likely to be conceived from the outset whereas the latter are more likely to evolve during the course of analysis. Computer applications in archaeology have traditional­ ly fallen into two principal areas: firstly that of sophis­ ticated filing systems for the collection, storage and retrieval of data, and secondly as tools to perform statistical and mathematical analyses. A third ancilliary area has developed which includes interests such as word­ processing and graphics, but the basic division holds good. This distinction is integral to the Danebury computing and correlates with the two types of data-sets just described. The former area of computer applications are here regarded as primary investigations and the latter as secondary investigations which may be seen as pure research. Admitt­ edly, this is a somewhat arbitrary division with very little chronological significance since both types of inquiry tend to proceed in parallel. It will, however, serve as a framework for discussion in the rest of this 40

paper. I t appears t hat c omputer applications a re moving away f rom the b elief o f a f ew y ears ago i n a t otally computeri sed s ite towards a more r ealistic approach. This i nvolves a n appreciation of the l imitations o f computers and the d efinition o f a ttainable goals. This n ew r ealism i s a lso apparent i n database applications w ith the s truggle t owards a world-wide c omputer o rientated databank ( Chenhall 1 971, 1 59) b eing r educed t o a more modest p lea f or a national policy o f data s torage a nd r etrieval ( Thomas ( ed.) 1 983, Appendix A ). A n i mportant a spect of t his i s the d ecision t o c omputerise o nly particular parts o f a ny data-set. There i s nothing wrong w ith r ecording s ystems that a re partially c omputerised a nd partially paper-based a s l ong a s the two a re adequately l inked by some means of c ross-referencing. I t i s preferable a t the d esign s tage t o i nclude a ll i nforma tion i n the appropriate f ile that i s l ikely to b e n eeded i n a ny computerised a nalysis. A n example o f this i s t he a nimal bone data a t Danebury which has b een codified f or c omputer a nalysis based on a n 8 0 c olumn c ard i mage. Only bone data that c an b e satisfactorily codified o r measured h as b een r ecorded o n computer. O ne column i s a tag t o r emind t he bone a nalyst t o consult the written r ecords where extra i nformation i s s tored. This i s c onsidered to b e a n essential f eature, without which the animal b one a nalys is would b e s everely r estricted. Much a rchaeological data does not f it i nto convenient categories w ithout a d rastic l oss o f i nformation. For example, a whole s eries o f s imple a nnotated s ketches a re kept which d escribe characteristics o f c ertain bones, but even w ith the available f acilities i t i s impractical t o s tore these on computer. The i nitial question s hould n ot b e whether o r not t o c omputerise t he data but rather which types of d ata c an profitably b e c odified and computerised. The a ll-or-nothing v iewpoint a nd the pursuit o f a s tandardised automated r ecording system w ill only succeed i n a lienating many non-computing a rchaeol ogists. Computing p riorities have to b e e stablished and t raditional t echniques i ntegrated w ith the n ew automated ones. At Danebury much data has not b een committed to computer b ecause t he p lanned a nalyses d id not j ustify t he r esources i nvolved. A nother t raditional f eature o f c omputerisation which many a rchaeologists f ind o ff-putting i s the u se of r estrictive p ro f orma r ecording s heets. I t has b een c laimed that the enforced c larity o f thought a nd t he n ecessity o f h aving t o say ' yes' or ' no' rather t han ' perhaps' i s o ne o f t he b iggest b enefits of u sing a machine ( Pryor 1 980) That t his p rocess o f i ncreased r igour i n data c ategor ' isation i s b eneficial i s not d isputed h ere a lthough i t i s d ifficult t o s ee why c larity o f t hought cannot p roduce a n a nswer o f ' perhaps' Archaeological data i s not a lways s imply b lack o r white, this r ather o ld-fashioned i dea of n eeding a y es/no a nswer s eems t o go back t o t he i mposed b inary l ogic o f the early days o f c omputing. I t i s possible to p rocess a .

.

much

w ider

range

o f

a nswers

i ncorporating

4 1

l evels

o f

b elief,

the ' binary mentality' i s no l onger r equired. I t must b e emphasised t hat c omputerised data c apture p rocedures c an and must b e f lexible enough to cope w ith i ntended r eplies. I t i s u ndeniable t hat s ome p ro-forma computer data-capture sheets have r estricted a rchaeological thought a nd r ecording i n the f ield a nd c reated a backlash o f a nti-computer f eeling. At Danebury, data i s c ollected i n s ite notebooks duri ng excavation t o a llow u nrestricted data c ollection which c an then b e r eassessed i n a post-excavation environment. I t i s h ere that the computerised codification a nd r ecording o f a ny particular data-category i s p erformed. This i s t he r esponsibility o f t he specialist worker who w ill c arry out most o f t he a nalysis a nd writing up. The Danebury t eam consists o f a number o f s uch workers w ith specific a reas o f expertise who obviously i nteract w ith each other but a re p rimarily c oncerned with their own d ata-set. I t i s conside red t o b e essential that they a re i nvolved i n the s tructu ring o f their own data-set s o t hat r easonable questions c an b e a sked o f the computer. Requests f or c omputer a nalys es a re d iscussed by the r elevant worker a nd the author who t hen a cts a s "an i nterface with the machine". The Danebury data a re entered o nto the ICL 2 900 mainf rame a t North S taffordshire P olytechnic v ia punched cards. This operation i s c arried out a nnually i n order t o k eep up with the o ngoing excavation. This may appear a s omewhat o ld f ashioned approach to data entry i n these days o f s elfvalidating data-capture p rograms but has s hown to b e more efficient overall. I gnoring d evices s uch a s mice and l ightp ens which a re not common-place, present t echnology d ictates t he u se o f a k eyboard and this i nevitably means a bottleneck. I t has p roved t o b e much more cost effective, i n t erms o f the a rchaeological budget available, t o employ p rofessional data-preparation s taff t o punch c ards than f or a rchaeologists t o l abour t ediously f or untold l engths o f t ime a t a keyboard. This s ystem works well f or Danebury b ecause data-entry i s not v ia a DBMS, the data b eing s tored i n s tand-alone f iles. DBMS's have o ther r estrictions b es ides b eing c omparatively s low at the data-entry s tage; t hey a re c onsumptive o f t ime a nd memory a nd t end t o b e either ' case-orientated' o r ' variable-orientated', t heref ore n eeding to b e i nitially s elected w ith t he application i n mind ( see Voorrips 1 984, 5 2 f or a more d etailed d iscuss ion). This i s not i n c ontradiction t o the earlier a rgument which was against a rchaeologists r eproducing what already exists a nd not a gainst programming p er S e. I n c ertain c ircumstances D BMSs a re f ine a s t ools f or data-collection, s torage a nd l ow-level a nalysis. At Danebury, a s a t most other s ites, t he range o f applications i s w ide, v arying f rom catalogue-like l istings t o numerical f iles f or s tati stical analysis. The range o f h igh-level l anguages available o n most mainframes, w ith their v arying s trengths, makes

any

application

Within

t he

possible.

machine

t he

Danebury

4 2

data

a re

s tored

i n

a

s eries o f i ndependent but r elated f iles which a re o rganised i n a s imple two-tier h ierarchy. A main f ile contains r ecords o f each p it d escribing i ts morphology, r elationships a nd contents. A s equence o f p resence/absence f ields a re used t o define whether o r not a particular p it c ontains a n entry i n any o f the f ive s ub-files. These s ub-files a re r eferenced t o the main f ile by a u nique c ontext number a nd h old i nformation o n the pottery, b riquetage, a nimal b ones, querns a nd s tone a nd small f inds. I nformation i s o rdered i n t he u sual h ierarchical manner c onsisting o f f iles which a re made up o f r ecords c ontaining f ields. A f ield b eing t he smallest p iece o f i nformation r elevant t o the current p roc ess whether i nput, r etrieval o r other a nalysis a nd i s, therefore, variable. The p rimary i nvestigations a t Danebury have t aken t he f orm of a n i nformation r etrieval s ervice o ffered b y the author t o the other workers. Requests have mainly b een f or various c ounts a nd a ssociated s tatistics concerned with i ndividual f iles. I nformation c an b e r etrieved a t d ifferent l evels; t he f ile i n f ull a s i t s tands, s elected complete r ecords, s elected f ields f rom a ll r ecords o r s elected f ields f rom s elected r ecords. All r etrieval programs have b een written i n COBOL b ecause o f i ts ability t o handle t ext. Although COBOL i s a rather v erbose l anguage, once basic r etrieval p rograms a re written they a re s imple t o adapt. This l anguage also has a n umber of u seful p rocedures i ntrinsic to i t, not l east o f which i s the SORT f acility which c an perform complex h ierarchical s orts o n s elected k ey f ields w ith j ust a f ew l ines o f s imple p rogramming. The a nimal bones, f or i nstance, have b een sorted by bone type w ithin each species; the data f ile b eing f ive megabytes i n s ize and y et the p rocessing t ime was l ess than one minute. The

t otal

number

o f

r etrievals

p erformed

t o

h elp

p roduce t he r eport are t oo numerous t o l ist h ere although two of the more i nteresting o nes a re worth mentioning. A p rogram was written t o phase t he contexts based o n the pottery typology u sing f orm a nd d ecoration ( Cunliffe 1 984). For each c ontext this p roduced a ' preferred c eramic phase' w ith a ' reliability factor' based o n the appropriate number o f i ncluded sherds. To t est t his phasing the 9 47 p its excavated during the f irst 1 0 y ears were s eriated u sing 6 f abric types ( Lock 1 983). This i s a n example o f t he d ivisi on b etween p rimary a nd s econdary i nvestigations b ecoming somewhat b lurred. The s eriation t echnique i nvolved the u se o f multivariate s tatistics but t he a im o f establishing a r eliable phasing i s obviously o f p rimary i nterest. S en at i on was s uccessful not o nly i n p roducing a n o rdering o f t he p its but also b ecause i t enabled a v ery f ine c hronology f or t he l ast 1 50 y ears o f the s ite's p re-Roman u se t o b e c onstructed. Using these c losely-defined s ub-phases i t was p ossible t o s tudy changes i n the f orm a nd d ecoration o f the pottery i n great detail. Study o f t he a nimal bones a lso c ombined p rimary a nd s econdary considerations, the a im h ere b eing t o construct a n a nimal b one a nalysis package. S everal p rograms

h ave

b een

i mplemented

4 3

t o

c ount

the

r elative

p ropo-

r tions o f species u sing d ifferent methods, t o age t he bones again by different methods, t o p erform a variety o f s tatist ical a nalyses o n bone m easurements a nd a whole r ange o f l ess complex r etrieval operations u sing t emporal a nd/or spatial d ivisions ( Grant 1 984 f or a rchaeo-zoological d etails). A s a lready mentioned s econdary i nvestigations a t Danebury p rogress alongside the primary i nvestigations a nd t he boundary b etween t he two can b e i ndistinct. A reas o f pure s econdary i nterest c an, h owever, b e i solated. I t i s i mportant t o r eiterate that s econdary i nvestigations o ften i nvolve the g eneration o f n ew data f iles d erived f rom the data f iles o f p rimary concerns ( as w ith a ll t hree examples b elow) b ecause the f ormer a re not u sually d efined a t the outset a nd a re not, t herefore, i ntimately r elated to the structuring o f the data. The f irst example i nvestigates t he effect o f employing d ifferent methodological approaches t o a l arge data-set ( Fletcher a nd Lock, i n p ress). A p roposed methodology, u sing a s imple t echnique o f s tatistical s ignificance t esti ng, has i ndicated the m eans by which i mportant spatial a nd t emporal t rends c an b e e stablished. Subtle r elationships b etween variables c an b e i dentified which m ight o therwise b e missed i f the often more a ttractive i mmediate u se o f multivariate s tatistical t echniques was applied. A nother f ruitful l ine o f s econdary i nvestigation has b een i nto the question o f pottery quantification ( Lock 1 984). I nteresting d ifferences c an b e shown u sing either s herd count or s herd weight t o establish r elative f requenci es. Some f orm o f ratio s eems t o b e n eeded, with various v ersions h aving b een s uggested a nd t ested. The third example i nvolves computerised pattern p erception a nd has b een t he f ocus o f a g reat d eal o f s tudy a rising f rom the n eed f or a r igorous method t o i dentify p ossible 4 -post s tructures w ithin d ense d istributions o f post h oles. P rograms h ave b een written t o f ind all o ccurenc es o f s uch patterns w ithin u ser-controlled l imits. I ntere sting comparisons have b een d rawn b etween t he computerised r esults a nd t he r esults o f a v isual a nalysis p erformed s eparately. Tests of s tatistical s ignificance s uggest t hat human pattern p erception i s s trongly a ffected by p reconcept ions. The density o f the point d istributions i s e specially i mportant; a s d ensity i ncreases t he human b rain i dentifies f ewer o f the actual s hapes t hat a re t here a nd compensates by i ncluding s hapes which a re outside the o riginal s earch parameters, ( Fletcher a nd Lock 1 984, L ock 1 984). The

conclusion

f rom t he

d iscussion

o f

p rimary

i nvest-

i gations s uggests t he n eed f or r ealistic g oals t o b e s et i nitially. A philosophy s imilar t o t hat c oncerning modelbuilding and t esting i n g eneral c an b e applied h ere, s tarti ng w ith s imple questions t hat can a ctually b e answered a nd l etting

t he

analysis

g radually

4 4

b ecome

more

complex.

I t

applies equally t o i nformation r etrieval exercises a nd s tatistical a nalyses, the l atter c ase b eing fully a rgued elsewhere ( Fletcher and Lock, i n p ress). Further concluding r emarks can b e applied specifically t o s econdary i nvestig ations. These analyses by t heir v ery nature have a n a im which i s d escribed w ithin the c ontext o f a n a rchaeological p roblem a nd a re p erformed o n specialised data f iles. Because o f the p rocessing p ower r equired t hey have t raditi onally b een p erformed on mainframe machines. This combina tion o f a r igorously defined goal a nd mainframe back-up h as u sually meant s uccess i n t erms of s tated p roblems b eing s olved a nd published. S tatistical t echniques exist which w ill p erform analyses r equired b y archaeologists. Much on-going work, however, i nvolves p eople who a re j ust a s i nterested i n the t echniques t hemselves a s i n the a rchaeological r esults. Whallon ( 1984) i dentifies t he ' interesting t echnique i n s earch o f a n application' s yndrome which u ndoubtedly exists. The r emaining important p roblems a re archaeological a nd l ie w ith t he o ften unsuitable quality o f the data a nd w ith the i nability of archaeologists t o c onstruct adequate models to i nterpret the r esults. I n many ways a rchaeologi cal theory i s not k eeping up with t echnological advances. C luster a nalysis i s a good example; there i s continuing s tatistical d iscussion over the theoretical v alidity o f various methods, but the r eal problems f rom a n a rchaeologi cal p erspective a re i n the s election of attributes a nd, t herefore, whether o r not the r esulting c lusters mean a nyt hing within a n a rchaeological f ramework. The s ame applies t o s eriation w ith the underlying a rchaeological a ssumption t hat t ime i s r esponsible f or any i solated t rend. Archaeologists entering the f ield o f c omputer applications w ill f ind many new d istractions t o lure t hem away f rom their i nitial concerns. Computers a nd s tatistics a re, h owever, capable o f encouraging n ew theoretical approaches t o the c ollection a nd i nterpretation o f a rchaeological d ata. These n ew t ools are powerful a nd i ntricate a nd should n ot be used g libly, f or suitable applications w ill s how the n ew d irection t hat a rchaeology must eventually f ollow.

REFERENCES B erger,J.

1 972.

Chenhall,R.G. r ess r eport", Cleere,H.

Ways

of

s eeing.

L ondon.

1 971. " The archaeological data bank: a p rogComputers a nd the H umanities, 5 (3), 1 59-69.

1 984.

" Only

connect",

i n

Martlew,R.

( ed.),

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9 -20. Cunliffe,B.W. 1 984. Danebury. A n Hampshire. CBA Research Report No. 5 2, F eyerabend,P.K.

1 978.

Science

4 5

i n

I ron A ge h illfort Volumes 1 a nd 2 .

a f ree

s ociety.

i n

L ondon.

Fletcher,M and Lock,G.R. 1 984. "Post built structures a t Danebury h ilifort. An analytical s earch method with s tatist ical discussion", Oxford Journal of Archaeology, 3 .2, 1 75-196. Fletcher,M. a nd Lock,G.R. I n press. " Investigating r elationships within l arge-scale data-sets a s a precursor t o the application of multivariate t echniques", i n Voorrips, A. ( ed.), i n press. Grant,A. 1 984. 1984, 4 96-548.

"Animal

husbandry",

i n

Cunliffe,B.W.

( ed.),

Lock,G.R. 1 983. "Computer assisted s eriation of the p its at Danebury h ilifort", Science and Archaeology, 2 5, 3 -8. Lock,G.R.

1 984.

Computing

Danebury h illfort a case Department of Computing,

and

statistics

i n

archaeology;

study. Unpublished Ph. D. thesis, North Staffordshire Polytechnic.

Martlew,R. ( ed.) 1 984. I nformation s ystems i n a rchaeology. New Standard Archaeology, Alan Sutton, Gloucester. Pryor,F. 1 980. "Maxey, micros and myself a personal assessment f rom the a rchaeologist's v iewpoint", i n Stewart,J. D. ( ed.), 1 980, 9 9-102. -

SERC. 1 982. Research s tudent a nd s upervisor. A d iscussion document on good supervisory practice. Swindon. Smith,K. 1 977. "The excavation of Winklebury Camp, Basingstoke, Hampshire", Proceedings o f the P rehistoric Society, 4 3, 3 1-131. Stallard,Y. and Gray,W. A. 1984. "Creating a conservation record database u sing a r elational database management system", P roceedings Computer Applications i n Archaeology, Birmingham,

7 8-92.

Stewart,J.D. ( ed.) 1 980. Microcomputers i n Archaeology. Museum Documentations Association, Occasional Paper No. 4 . Thomas,C. ( ed.) archaeology. The

1 983. Research objectives i n British Council for British A rchaeology.

Voorrips,A. 1 984. carrying capacity", Voorrips,A.

( ed.)

mathematical

" Data catchment a nalysis a nd c omputer i n Martlew,R. ( ed.), 1 984, 4 5-53. i n

methods

press. i n

To

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the

past:

a rchaeology.

Whallon,R. 1 984. "Past a nd future o f quantitative methods i n archaeology: problems solved and s olutions without problems", paper r ead to the Union I nternationale d es Sciences P rehistoriques et P rotohistoriques Commission 4 conference, Voorrips, A

Amsterdam. ( ed.),

i n

P roceedings

press.

4 6

t o

b e

published

a s

THE F RIENDLY USER Martin

Carver

No-one doubts t hat the computer i s u seful "a u seful tool" i s the s tandard g reeting, e specially o f t hose not quite s ure what i t does " in t he s ervice o f a rchaeologists", i s t he hasty r ider, i n c ase i ts principal v irtue turns out t o b e making p edestrian r eport-writers r edundant. But t he c hoice i s not r eally which k ind o f l ip-service w ill prove p olitically expedient, but how we can harness, f or t he i nvestigation of human l ife, the most v ersatile i nvention s ince t he plastic bag; harness i t moreover f or a p rofession which has o nly j ust b egun t o k eep a ccurate r ecords a nd has s carcely mustered enough r esources t o p roduce r easoned accounts o f quite small p ieces o f f ieldwork i n l onghand. When t hree o r f our methods o f s ite r ecording may b e i n u se i n a s ingle Organisation; when analysis of s ite r ecords has s carcely d eveloped b eyond l arge scale geometric d oodling, a nd above a ll when the hunter-gatherer economy which the f ield worker i s obliged to f ollow a llows bare s ubsistence rather than i nnovation, i t i s hardly s urprising that c omputers have b een s ome t ime knocking a t the door o f t he s ite hut. -

-

I n spite o f, p erhaps b ecause o f, a great d eal o f b reathless p roselytizing, i t i s t he computer's r elevance t o c reative a rchaeology t hat i s s till doubted, a nd i t i s the w isdom o f i nvesting p recious thinking-time i n s uch a potential wild-goose chase t hat must b e weighed. I am not speaking h ere of t hose f or whom the g immick i s f ar more f ascinating than what i t does; t he owner o f the m ink golfball warmer and the musical watch. I am t hinking rather o f t he s erious a rchaeologist who i s deeply conscious o f t he mental effort r equired t o make s ense of a n excavated s equence; conscious a lso o f the constraints on h is own i maginative p romptings, of the t empting short cuts, of the i nadequacy o f numbers a s i nept i n t heir way a s words, d rawings or photographs a t expressing or suppressing the t houghts o f the educated man c onfronted with the bones o f h is a ncestors. And y et these thoughts a re the s tuff o f a rchaeology a nd have b een f or 1 50 years; w ithout them w e should h ave none o f t he building b locks o f p rehistoric, Roman o r M edieval material culture, no barrows a nd n o mottes, no f orts a nd no h enges, no k ilns and no k ill-sites. I f s uch i maginati ve a scription a nd ( often f ar-fetched) analogy have i ntroduced, a s s ome have c laimed, b ias i nto t he f ield d irector, i n many more cases i t has p rovided t he power t o s et a n image dancing a nd a n ew g eneration o f -

s tudents

w orking

t o

i ts

music.

This p reamble has computer i s not s imply a ( Cooper, this v olume) a i mplication, a d ifferent p rofession i n a nd out of

b een p rompted b y a b elief t hat a "useful t ool", i t d emands rather d ifferent way o f thinking, and, by o rganisation o f the a rchaeological doors. The s uggestion i s t hat the

4 7

hunter-gatherer phase of a rchaeological i nvestigation s hould now evolve i nto a more s tatic cultivation o f the data, i n which the rushing, s nooping, Sherlock-Holmesian f ieldworker i s r eplaced by a communications n etwork p owered by computers. H ere t he p iecemeal a ttributes o f past l ife a re s ystematically l ocated a nd l abelled ( at County S MRtS), a nd sorted i n a theoretical a rchive of the " National Corpus" ( held by NMR or HBMC), which c an b e f ed f rom t ime t o t ime with h igher-tier i nformation f rom excavations, o r i nterventions of any k ind, o n the g round. Reviewing t he evidence f or any a spect o f a ntique p ractice i s then r elati vely t rivial; f ar f rom b eing a P hD i n i tself, a s now, i t i s a matter o f routing d igested extracts k eyed by a p reexisting v ocabulary ( "burials", " barrows", " bronze a ge") out of the national computer f iles i nto the s tudent's mail basket. What then w ill students actually d o f or a P hD? P resumably they can concentrate o n t he part which has always appealed most, namely complaining about the quality o f the evidence, a nd t rying t o draw conclusions f rom i t. I f the academic b ranch of t he p rofession b ecomes sufficient ly adventurous, co-operative r esearch t eams which i nclude post-graduates might conceivably b e f ormed i nside u niversi ties a nd p ersuaded t o address themselves to matters o f common i nterest. This i s no more t han has a lready h appened d ecades ago i n t he S cience Faculty, a nd even E nglish, y es, even History has s ought t o f ilter the babble o f the documentary r ecord a nd s earch f or order and meaning i n i t w ith s tandard DBMS s oftware. Unless a rchaeology l ecturers a re i ntrinsically l ess imaginative, l ess c apable o f c ooperation w ith other human b eings, a nd more i nclined t o paranoia, and i ntellectual s chizophrenia t han o ther a cademi cs, f or which t he evidence i s not p resently d ecisive everywhere, t here s eems to b e l ittle r eason why a rchaeologi cal r esearch i n u niversities s hould not s o d evelop. I t would b e f airly s imple t o make every application f or a DES o r university g rant p rovisional on the computer-compatible c reation, or u se, o f a data base b eing i ncluded i n the p ost-graduate programme. Who knows, i t m ight even b e happening already. This does i n f act s eem to b e the only way i n which the so-called ' academic' part o f t he a rchaeological d iscipline c an c atch up quickly a nd painlessly, a nd w ith m inimum damage t o i ts p ride, with t he theoretical basis o f d ata r etrieval on which their t eaching a ctually d epends. Whether we d eal with earthworks, s trata, s eeds o r f lints, the evidence which emerges actually does s o a s t he end p roduct o f a type o f " systems analysis", either p erformed i n the d eepest r ecesses o f t he b rain, a s w ith my " serious a rchaeol ogists" a forementioned, o r more consciously a s a p rocess o f definition, taxonomy, a nalysis a nd presentation. C ropmarks, earthworks, a nd s trata must a ll p ass t hrough t his t ransmogrification b efore t hey c an j oin t he corpus o f w ellk nown ' facts' Once i t was t he magic f lute o f a n a rchaeol ogist w ith a b ig name which ensured t he s afe-conduct o f .

4 8

r 9 5 R U F

AU

1

©

F igure

49

these f acts to immortality. Lately i t has b een the emergence of a generalised, unchecked, a nd often uncheckable, j argon which provides the entry v isa. Clearly the u se o f computers, a s the u se of evocation t hrough a nalysis o f a ny k ind, d epends o n t his f irst s tep b eing t otally f ree o f humbug. When something called a " Roman pottery k iln" i s admitted t o the immutable store of human knowledge, w e must b e s ure what a ll three of t hose words mean. When the evidence consists of s ets of components each equivocal i n definition ( a white-flecked l ayer, a wall-trench), the c hallenge o f t axonomy, y et a lone quantification, s eems f ormidable. And y et t his i s the paradox, the nub of the problem; t his i s the a rchaeological comedian that h as k ept the i nformation t echnologist a nd data handler waiting i n t he wings f or 2 0 y ears. Without g eneralised, s tandardised, agreed definitions of the elements o f archaeological data, we cannot harness the a nalytical p ower o f c omputers t o build models o f the past. These definitions will not easily b e agreed; by s ome because not t o do so i s f or them a basic t enet o f the d iscipline the r eason they b ecome a rchaeologists; b y others b ecause i t i s t oo d ifficult t o do well; by o thers b ecause a common vocabulary f or strata will weaken o bserva tion a moral danger, l ike t he mythical "director b ias" thought to b e i nherent i n every notebook; others again b ecause i t would weaken the i nterpetation possible f rom strata broadly observed and f lexibly d efined: the possibili ty t hat a common l anguage will produce c ommonplace s tate-

-

ments. To s how that a ll these f ears a re g roundless i s b eyond the s cope of this paper. What I w ill show i s t hat i t i s possible t o c reate i n advance, f or application t o a ny exercise i n the r etrieval o f a rchaeological data, a s ystem which harnesses the power o f the computer a nd s acrifices none of the archaeologist's c reative potential; on the c ontrary every a rchaeologist c an b e more c reative w ith a computer. The a ssumption made h ere i s t hat a rchaeological data a re susceptible t o u nequivocal d efinition w ithin a conceptual h ierarchy comprising component, c ontext, f eature a nd structure, each o f which consists o f a s et o f the others. Thus, a s tructure i s a s et o f f eatures, a f eature i s a s et of contexts and a context a s et of c omponents. Only components need to b e d efined b efore a n excavation b egins, a nd the contention i s that this may b e d one through r econnaiss ance a nd evaluation ( figure 1 ). Each c omponent i s a llott ed a n a nalytical d estiny, t hat i s, i t i s pre-defined i n o rder t o make s ense o f a n a spect o f t he s equence. This i s a v ery d ifferent approach to t hat o f P itt-Rivers o r Barker ( 1977), both of whom maintain the s anctity o f observation; i n these earlier s ystems a n excavator was encouraged t o r ecord " everything" even though i t h ad no c ertain r ole i n the i nterpretation. I f p redefinition i s r equired f or a nalytical

purposes,

this

' innocent'

5 0

s crutiny of

the

s trata

must b e c oncentrated w ithin t he evaluation phase, f rom which a t axonomy w ill emerge. A s each element i s d efined a nd g iven a name, a nd g iven parameters which can b e unequiv ocally r etrieved i n subsequent f ieldwork, s o t oo will the u se t o which they w ill b e put i n the subsequent a nalysis. F igure 2 i s a c rude a ttempt t o l ist some of t he more obvious f orms o f a nalyses possible f rom excavation r ecords, a lthough not everyone o f even these f ew i deas have actually b orn f ruit. While everyone i s p ersuaded of the a nalytical p otential o f components s uch a s s eeds, o r o f spatial d istributions s uch a s a pattern o f post-holes, the u se o f context d escriptions, f or example, has y et t o b e f ully worked out, o r adequately l isted. The holding-theory f or t he s ystem i s t hat data c an b e r ecovered i n two f orms, the m easurable a nd the i ndefinite. This system d eals o nly w ith t he measurable attributes of composition a nd space, but i t i s no part o f the case t hat the i ndefinite data i s valuel ess o r even t hat i t i s i ntrinsically unmeasurable o nly t hat i t was not measurable within the particular c ircum-

-

s tances

o f

i ts

r etrieval.

A ssuming a c ertain minimum application of c are, every excavation will produce, i n addition t o measurable d ata s uch a s the d imensions o f post-holes a nd the s et o f a ll l ong bones, l ess c ertainly bounded data-sets, s uch a s the s tain l eft by a d ecomposing body, o r the number o f w ings of d ead i nsects. I t i s t he a rchaeologist's j ob to stabilise t he r etrieval s ystem so that i nformation n eeded f or t he analysis does not wander f rom t he unequivocal t o t he equiv ocal grade during the excavation. This c an be done only by t he imposition o f a s ampling strategy s uch a s i s p rovided by the system o f r ecovery grades g iven i n f igure 3 . By way o f i llustration, the data s ets and a nalytical • i tineries expected of a s andy s ite such a s Sutton Hoo might b e b riefly d iscussed. Survival h ere i ncludes t runcated n egative f eatures under p lough, n egative f eatures s crambled t o a depth of 3 0cm ( by b racken) u nder turf, and i ntact f eatures c ontained i n s trata up t o 8 0cm i n d epth. C ontext d efinition varies f rom s ilhouette burials t o buried s oils whose upper a nd l ower horizons may b e d efinible o nly t o w ithin + o r 1 0cm. The s ame f actors apply within barrows where v isibility i ncreases ( unevenly) over the 4 -7 metres f rom the turf to burial chambers c lose t o the water table. Applying l evel D r etrieval ( using only water a nd w ind enhancement), a ll post-holes, a ll g raves, all d itches a nd u p to 6 0% of s take h oles would b e r ecoverable i n most a reas. All d ecayed burials have b een d etectable a t t his g rade s o f ar, but only a 7 5% s uccess rate i s expected overall. Thus l evel E r etrieval u sing c hemical a nd physical methods o f enhancement ( eg. ultraviolet l ight) would b e r equired t o r ecover t he data-set applicable to the r emains o f human b eings, which i s i n turn r equired f or a nalysis -

l eading

t o

social

Measurable

structure. a ttributes

o f

5 1

contexts

a t

l evel

D

a re

F ig.

Table

2 : Source

and

Purpose

i n post-excavation

2

A nalysis

v ailable Data

T ype

of Analysis

Y ield

a t L evel

CONTEXT Composition on

s ite

S edimentology a nalysis),

( particle s ize

radioactive e lement

D istribution of material

( 1);

sequence

l ayer

( 2)

f unction of

I dentification of l ayer; how d ecayed,

date

( 3)

C

how formed;

( 4)

0

d ating Paleobotany: p lant

p lant

t ype and

A ctivity;

a ssemblage

p lant use;

environmental

I nsect death a ssemblage

Ambient conditions; materials

Bone analysis:

t ype,

Animal

assemblage and pathology

bone:

mammal

conditions

organic

in

a ctivity

t ypology

and

d iet,

p lots

w ithin

Three

context

d imensional

breeding,

bone-

( 7)

bones:

C ambient

( 8)

D demography,

d isease

( 9)

( 10)

A ctivity;

assemblage D istr.

vanished

C

decay products of vanished materials;

analysis

�Artifacts:

D

0

Human bones: Quantitative/quantities

( 5)

( 6)

u sing i ndustries Small

implied

s equence

p lotting;

r eLating dating;

cultural

( 11)

A ctivity,

angle of d ip

D

u se;

C methods of d iscard;

presence/absence of b uildings

( 12)

C

Context

F EATURE Shape, ( paper)

d imensions,

t ypology,

r econstruction

I dentification; of construction;

use;

a ctivity;

metho.

mode of destruction

or d isuse;

c ultural

resources;

duration of u se

context;

e conomi.

( 13)

C

S ITE GEOMETRY

Stratification

d iagram

sequence of f eatures

Seriation

s equence of buildings, a ctivities

Dating A ssemblage

( 14)

( 15)

d ate of e vents content and

d istribution

character of phases

P hasing

s ite

5 2

model

e vents

C C

F ootnotes t o f ig.

2

1 .

F or e xample d etermination of m ode o f d estruction o f b uilding b y f rom p lot o f l ayers c ontaining c harcoal.

2 .

U ndocumented p ractice w hereby l ayers a re a ssigned r elative a ntiquity b y c olour a nd c omposition. N o p roven r eliability.

3 .

F or e xample, t he r ecognition o f a p lough-soil ( Keeley a nd M acPhail, 1 981).

4 .

f rom i ts m acrostructure

P article s ize a nalysis h as b een c laimed a s p roviding r ecognition of v arious a nthropogenic o r n atural

5 .

f ire

E xamples:

a ctivity patterns

p lant r emains

e pisodes:

i n a b akery

p uddles,

p aths,

m iddens.

f rom d ropped g rain;

d iet f rom

i n a l atrine o r f rom s tomach a rea of a n i nhumation,

c ultivation of c rops i n a ccessible a djacent a reas i mplied b y presence of g rain a nd c ereal-specific w eeks i n s ettlement d iscards; v egetation s equence i n t he a djacent a rea i mplied b y p ollen s equences d eposits. 6 .

E xamples:

p articular

c onditions;

i nsect a ssemblages

p resence of s pecific f eeders

a nobium p unctatum i mplies w ood; C arver, 1 979)

m oths

7 .

S ee,

f or e xample,

A rmitage

1 981,

8 .

S ee,

f or e xample,

R ackham,

1 982.

9 .

S ee,

f or e xample,

D awes a nd M agilton,

1 0.

1 2.

i ndoor or o utdoor

i mplies v anished m aterials:

i mply

S chmidt

t extiles.

( Kenward,

1 978;

1 972.

1 980.

C oncentrations o f c ertain b iophile e lements l eft b y d ecayed b odies, B ruce-Mitford,

1 1.

i mply

i n p eat

1 975,

A ctivity

f rom a ssemblages;

c ultural

c ontext f rom a rtifact i dentities,

E xamples: b uilding;

r elative d ating f rom s tylistic m aterials,

d istribution of p rimary m aterial d istribution of b uilding d ebris

o n a f loor

1 3.

S ee,

H ope-Taylor 1 977.

1 4.

S ee H arris,

1 979;

C arver,

1 5.

S ee H odson,

1 968;

C arver i n p ress

1 983.

5 3

( a).

t ypology;

d istributions,

e tc.

i mplies u se o f

i mplies d estruction s equence;

u se o f p itched f lint o r r ubble d istribution t o 1 977). f or e xample,

s ee

C hapter 8 .

i mply buildings

( Barker,

colour, pH, a nd t exture o f the s and matrix. The l atter however c annot b e r ecorded by observation, but must b e determined by s orting i n the l aboratory. Every context would therefore have to b e s ampled to establish the v ariati on of the matrix b etween contexts. F ull ' context descripti ons' written on s ite cannot b e u sed f or comparative a nalys is, and therefore a re not i ncluded i n t he d ata p laced o n c omputer f ile, but r elegated to the ' indefinite r ecord'. I n f act when the analyses to b e imposed on the measurable r ecord a t Sutton Hoo were actually b eing s tudied, no d irect analytical purpose f or the ' hearsay r ecord' of t he d iscarded matrix could b e f ound. I n f act the f ill of, f or example, a p it a t Sutton 100 ( as on many s and a nd g ravel s ites) i s not a n i ndependent v ariable, but i s d ependent rather o n t he t exture d ifferential b etween t he f ill and the ( natural) d eposits t he f eature has cut. I t i s t his d ifferential, rather t han t he f ill i tself, which has the a nalytical potential, a nd which, t herefore, may eventually enter the measurable r ecord. All f eatures, contexts a nd c omponents, i ncluding r etrieved components ( ="finds") a re mapped i n three d imensi ons i n the s tandard manner. The measurable s ite r ecord therefore consists essentially of a t hree d imensional array o f d efined components, the r ecord o f r ecovery l evels f or each, a nd the a rray of defined components, the r ecord o f r ecovery l evels f or each, a nd t he components themselves. The components a re b roken down i nto materials ( flint, pottery, s oil matrix . ..)‚ the materials i nto i dentified objects, a nd each object i nto a ttributes ( retouching pattern, hardness, pH . ..). A ny i ntervention at Sutton 100 ( i.e. a ny campaign of i nvestigation) w ill p roduce a s et o f f eatures each of which i s a s et of contexts, each of which i s a s et o f c omponents, each of which i s a s et o f objects, each of which i s a s et of a ttributes. Each s et c an b e entered o n a s eparate d isc ( as a s eparate f ile) o r i ndexed a s a s ubset of t he s et above i t i n t he h ierarchy. A common objection that a rises i n these s ystems i s that additional a ttributes may emerge a s s ignificant during t he excavation i tself, or during the entering of components on the f inds f iles. To a l arge extent, the p resent s ystem would wish to i gnore t his unanticipated i ncrease i n a nalyti cal potential, b ecause t o i ntroduce any n ew a ttribute would i nvalidate t he r ecords a lready taken. I n p ractice o f course, t he majority of a rchaeological s ites a re a lready f ull of g aps a nd h oles, a nd r epresent a h eterogeneous a nd i nconsistent s et of r etrieved data. I t would b e u nrealistic t o expect t he r ecording s tructure t o b e predefined f or more than a particular i ntervention, a nd i t i s t his which must s till r epresent a d iscreet consistent r ecord over a n a rea with known l imits. S ome f lexibility c an even b e i ntroduced i nto a particular f ile by c reating " empty f ields" w ithin each r ecord. However, such a f acility i s not n ecessary t o the system a nd may even threaten i ts cost-effectiveness. I t

i s

i ndeed

i mportant

t o

5 4

a ffirm t hat

the

i mposition

G U I D E T O I N F O R M A T I O N R E C O V E R Y G R A D E S

v


'

( 1 )

o f a machine-based data base management s ystem may not i n t he short t erm make a n excavation c ampaign cheaper. Hardware a nd software apart, the s ystem can only b e effective i f i t i s s erved by staff who were not there b efore: those who enter, those who edit, those who manipulate, s tore a nd p rogram t he data. This i s a n ew activity on the excavation s cene, not a nother part-time j ob f or the a lready overextended a rchaeological d illetante. The extra c ost i s j ustified by the additional power t o understand a nd make accessible the s eries of h istorical episodes which the a ct o f excavation uncovers. The system may t herefore b e summarised a s f ollows:the s et of components f or a particular r etrieval operation a s ite or a s et o f s ites on a particular t errain i s p redicted through evaluation. C ontext v isibility i s d etermined a t t he s ame t ime: those where survival i s good, where survival i s poor, where enhancement i s t o b e applied, each i s p re-allocated a g rade according t o the priorities of the excavation s trategy. Every element ( component, c ontext, f eature) i s a ssigned a s et of parameters, which a re i pso f acto measurable, which have a k nown contribution t o the analyses. The analyses, i n turn, a re k nown either f rom s imulation or experience, to have a particular contribution to make t o the s ite model. At this point i s i s possible t o d esign a r ecording a nd data base management s ystem t ogether with the appropriate analytical p rograms a nd g raphics o r other outputs. F igure 4 s hows t he content o f s uch a s ystem, g iving t he a nalytical i tineries f or each c lass o f r ecord, a nd t he f ormat f or s torage. This v ersion, actually p repared f or a t own s ite, has a ttempted a r econciliation w ith the l evels of data proposed by the F rere r eport ( DoE 1 975). -

-

I f t he a rguments h ere a re accepted ( and comparable systems have a lready b een put to u se i n s tratigraphically well-defined u rban s ites) then a machine-assisted data r ecovery s ystem can b e put to work w ithin a s ingle excavati on which i s compatible with t he a rchaeologist's overall d esire f or a t otally f lexible r esponse t o p henomena encountered underground. But h ow u seful w ill the r esult b e t o o ther s ites of the s ame r egion or t he s ame p eriod? Can the s oftware b e shared? I t i s c lear that the d efinition o f t he c omponents which express t he data depends p rimarily o n the t errain which c ontains t hem ( Carver 1 985). Two sand s ites c an b e compared, b ecause they offer t he s ame species o f evidence, f ar more easily than a s and s ite a nd a c halk s ite. A ny a ttempt t o g eneralise data f ields t o s uit more t han one t ype of t errain i s l ikely to r esult i n data so bland a s to s erve only t rivial a nalyses. However, s ince f ield units t end t o work i n d ifferent types o f t errain, t here a re problems f or their economy i n s uch d iversification. I f every s ite i s to have i ts own c omputer a nd i ts own purposebuilt s oftware, post-excavation p rogrammes w ill b e g reatly i nhibited, at l east over t he n ext d ecade. A n option m ight b e t o encourage units t o specialise, a s i ndeed most of the

5 6

successful computer-users already h ave: f or example i n L ondon o r the F enland. I n the f ree-market t o which we a re apparently d estined this w ill no doubt p rovoke the f ormati on o f the Rocky H ill F ort F ield G roup, Sandy S ites L td., o r Wet Strata I nternational. But not l east of the dangers o f this k ind o f specialisation i s that i nterpretation i s once again s queezed out of the i ntellectual i tinerary; s uccessful s tudy o f a r egion, a culture, o r period demands variety, a nd units, a t l east i n the p resent writer's j udgem ent, must b e d edicated to successful explanation o f the past rather t han data collection only. The alternative i s t o c entralise t he computer f acility, t o take the burden o f c omputer systems d esign, with a ll i ts current cutting o f c orners a nd bodged programs, out of the f ield units a nd concentrate i t i n a professional s ervice. I t i s i nteresting that the a rgument d rawn purely f rom the n eed t o a nalyse exacavated data a nd compare them, l eads naturally to a c entralised a nd v ersatile c omputer f acility, b ecause there t oo, i s where the a rguments d rawn f rom c ultural r esource management considerations a lso l ead. The variation i n the i ntensity with which the l andscape of the British I sles i s curated i s partly a n accident of h istory a nd, connected w ith i t, a r eflection of the uneven i ndustri al a nd agricultural i nvestment f rom T ruro t o Caithness. Management decisions on what i nformation i s r etrieved are o ften, a s i n other d isciplines, a r esult o f a chain r eacti on f rom l ocal a rchaeology t o sponsors i n c entral government o r elsewhere, which, a s has f requently b een a rgued, i s f ar too d ependent on the modern s ettlement pattern rather t han the a ncient. Whether we speak o f r esearch o r r escue, i t i s d ifficult to s ee h ow l ogical d ecision-making about a rchaeological f ieldwork c an happen other t han with the a id o f a national data base I t i s p robably worth r eiterating t oo that Britain, b eing a n i sland, i s particularly w ell s uited f or the examination o f a ncient s ociety through a l ong-term strategy o f exploration i n which c ultural r esource management f actors a nd academic k ey i ssues a re matched i n a machine-based r esearch planning c entre. At a l ower l evel t oo, t he l ogistics o f unit management do not a llow every n ew project to b e t ested easily a gainst t he existing s tore o f k nowledge. Not only i s a county SMR a n i nadequate ( and a rtificial) data s et, f or t he study of most p re-medieval p eoples, but i t i s u nreasonable t o expect a u nit manager t o b e up-to-date i n every expanding b ranch o f a d iscipline c overing s ix millennia o f partial ( and parti ally published) data. The c ase f or t he national c omputer option i s a rgued elsewhere i n t his book. I t c ould work, e specially i f considerable efforts are made to d evelop a nd o ffer the a nalytical s ervices which every excavation i ndividually d emands. I t would work moreover whatever s tructure British A rchaeology i s obliged to a ssume t o survive the p olitical c limate of the d ecade. The economic advantages o f buying h ardware a nd s haring s oftware w ill b ecome apparent a s more a nd more analytical p rocedures a re put t o the t est a nd

5 7

F igure 4

B IR M INGHA M

UN IVERS ITY F IELD ARCHAEOLOGY UN IT

GU IDE

S chedu le f o r G enera t ion , S to rage a nd P ro mu lgation o f P ro ject R eco rds

L EVEL D

A

No 1

S ITE

P RO MULGAT ION M OL TIPLI

T A

L E1 V 1 EL ‚SITE i

C W EX

e oo

p , p t

'

.

.

r CARDS I

J

I

S

[ J

L i

3

r

. . . .. . .. . .. 1 J . . . . . .

'I NTERPRETAT IONI

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r edrawn a ccording t o P hases/Periods

5 9

f ron s eriation.

e tc.

o f

create the f oundation for the next generation of academic questions. I t will thus b e possible f or f ield a rchaeologi sts to concentrate on the definition of data i n the f ield, on i ts enhancement, on i ts meaning, and on the c reation of s ite models which make n ew s ense of p rehistoric and h istori c s equences, whilst data base management a nd specific analyses a re developed by expert p rogrammers whose cost i s shared by the profession. This c ertainly i s a way to keep the all important u ser f riendly. -

REFERENCES Armitage,P.L. 1 982. " Studies on the r emains of domestic l ivestock f rom Roman, Medieval and early modern London: objectives and methods", i n Hall and Kenward ( eds.), 1 982, 9 4-106. Barker,P. A. 1 977. Batsford, London.

Techniques

of

Archaeological

Excavation.

Bruce-Mitford,R.L.S. 1975. The Sutton Hoo Ship Burial, Vol. 1 . British Museum Publications, London. Carver,M.O.H. 1 979. "Three Saxon Norman C ity", Medieval Archaeology, 2 3, 1-80. -

1983.

"Valutazione,

pluristratificati",

strategia ed

Archeologia

1 985. " Diggers and d igging Archaeologist, 3 , 2 6-8.

i n

-

i n press s eriation",

i n

a nalisi

nei

s iti

Medievale,

1 0,

4 9-71.

the

2 1st

century"

( a) "Theory and P ractice i n u rban Journal of Archaeological Science.

-

i n Como

t enements

The

Department

of

Publication

the

i n

Environment.

Rescue

1 975.

P rinciples

F ield

pottery

p ress ( b) " Dello scavo al l ettore", P roceedings Conference on archaeological method, 1 984.

Dawes,J. D. and Magilton,J.R. 1 980. "The Cemetery Helen-on-the-Walls, Aidwark", The Archaeology o f

Durham

of

of S t. York 1 2/1. of

Archaeology.

Hall, A.R. and Kenward,H.K. ( eds.) Archaeology i n the u rban context.

1 982. Environmental Council for British

Archaeology. Harris,E.C.

1 979.

Stratigraphy. Hodson,F.R.

P rinciples

Academic

1 968.

"The

Acta Bernensia

5 .

Hope-Taylor,B.

1 977.

of

Northumbria.

HMSO,

of

P ress, La

T ne

Yeavering: London.

6 0

Archaeological

London. Cemetery

an

at MUnsingen-Rain",

Anglo British

c entre

K eeley,H.C.M. a nd MacPhail,R.I. 1 981. "A S oil Handbook f or Archaeologists", Bulletin of the I nstitute of Archaeology, 1 8, 2 25-41. K enward,H.K. a ssemblages: 1 9/1.

1 978. "The a nalysis o f a rchaeological i nsect a n ew approach", The Archaeology of York,

Rackham,D.J. 1 982. "The small mammals i n the u rban environment; their r ecovery a nd i nterpretation f rom a rchaeological d eposits" i n Ha11,A.R. and Kenward,H.K. ( eds.) 1 982, 8 6-93. S chmid.E.

1 972.

An

a tlas

o f

a nimal

6 1

b ones.

London.

COMPUTERS

I N

FIELD ARCHAEOLOGY:

AGENTS OF CHANGE?

Paul Reilly

I NTRODUCTION Computers s eem l ikely t o p rove a s i nfluential i n f ield a rchaeology i n the l ate twentieth c entury a s the p rinting p ress was i n s cholarship a nd s cience f rom the l ate f ifteent h c entury. The a im o f this paper i s to h ighlight s ome o f t he ways i n which the i ntroduction of computers might a ffect t he future d evelopment o f t heory a nd method i n f ield a rchaeology. I n o rder t o d iscuss the p ossible i mpact a nd c onsequenc es o f t his new t echnology within a particular environment i t i s n ecessary t o d efine t hat e nvironment. ' Field a rchaeol ogy' i s a vague concept, a nd t his has allowed i ndividual a rchaeologists t o f ormulate t heir own i deas a bout what t he s ubject i nvolves. I dentifying a body of p eople who can p roperly b e d escribed a s ' field a rchaeologists', d istingu ishable f rom the much wider category of ' archaeologists p er s e' i s therefore p roblematic. One d efinition o f a f ield a rchaeologist i s a p erson who has r egular a nd d irect contact w ith primary a rchaeologi cal data a nd who i s i n part r esponsible f or t ransforming t his material i nto the more t ractable i nformation f ound i n a rchives a nd r eports. F ield a rchaeology i s t he basis upon which a ll o ther f orms o f a rchaeology d epend, a nd w ithout which t hese others would eventually s tagnate a nd t hen dry up altogether. C onsequently, this p rocess, i n which t he p rimary data g athered i n the f ield a re d istilled i nto more u seful i nformation, i s o ne o f t he most c rucial s teps i n t he c reati on o f n ew archaeological k nowledge. I t i s a f ocal point w here t he tools a nd methods u sed ( in t he i nitial d ata c apture a nd characterisation p rocedures) w ill have p rofound r epercussions upon t he s ubsequent d evelopment o f t heories based o n these data.

THE ARCHAEOLOGICAL KNOWLEDGE BASE A rchaeological k nowledge i s based u pon a n amalgam o f d ata d efinition, capture a nd manipulation. Each o f these operati ons c auses t he n ature o f t he objects u nder s tudy t o b e c hanged. This often means t hat the f inal p roduct c alled ' archaeological k nowledge' i s f ar r emoved f rom t he o riginal r aw data upon which i t was f ounded. • ' Raw' a rchaeological data f orm a c ontinuum w ithin t he l andscape. When a rchaeologists working i n t he f ield encount er parts o f this c ontinuum t hey i solate d iscrete material f ormations, s uch a s s trata a nd other contexts, a s ' primary'

6 3

data which can b e r ecorded. These units of data a re made ' operational' when they have b een i ncorporated i nto s ome medium which may b e c onsulted by others at a l ater d ate. This s tep away f rom t he p rimary data s ets to their s ymbolic r epresentations i n the r ecord w ill b e a ffected by the t ools a nd t echniques u sed t o make t his t ransformation p ossible. For example, the adoption o f p re-formatted r ecords i s l ikel y t o p roduce a more s ystematic r ecord than t he u se o f a f ree t ext l og-book which contains no explicit conventions. The l og-book w ill g enerally c ontain a r ecord o f what t he observer f elt were s ignificant a ttributes. By u sing a p ref ormatted r ecord, h owever,the s ignificant a ttributes h ave a lready b een s elected, p rior t o a ctual observation; t hus a ttribute f ields which a re l eft empty i mply t he absence o f what must b e a s ignificant attribute t o the s ystem. The absence o f any r eference to such a ttributes i n a l og d oes not mean these attributes were not observable, a ll i t d oes mean i s that this i nformation i s m issing. T his i s a n important point to b ear i n mind when computerising data s ets which was not c ollected w ith this purpose i n mind. Most archaeological data g enerated by f ield a rchaeol ogists i s descriptive i n k ind. According t o Ravetz ( 1971, 7 8) d escriptive data a re normally a s ample d rawn f rom a naturally existing population. They a re " found", u nlike experimental data which a re "manufactured". Ravetz ( 1971) a nd Majone ( 1980) have d emonstrated t hat t he nature o f a ny n ew knowledge i s partly d etermined by the methods u sed i n i ts p roduction. They i dentify s everal main s tages i n w hich t he o riginal r aw material i s modified b efore i t b ecomes i ncorporated i nto t he k nowledge b ase o f the r elevant d iscipline. The f irst c rucial t ransition occurs when d ata a re r efined i nto more u seful ' information'. A n a rchaeologic al example might b e t he conversion o f a s et o f r esistivity or spot-height r eadings i nto a c ontour p lan, o r the r educti on o f s everal s eries o f s tratigraphical r elationships i nto a Harris matrix. Such t ransitions often r equire c riteria o f r eliability and r elevance, a nd the application o f particula r t ools, such a s a n i nterpolation p rogram. These p ieces o f i nformation a re g enerally o f l ittle u se o n t heir own. Later s ome o f this i nformation w ill b e u sed a s ' evidence' w ithin a n ' argument' t o s upport t he v alidity o f s ome ' conclusion' o r ' interpretation'. These c onclusions a nd i nterpretations have to b e d isseminated a nd accepted b efore t hey c an b e c onsidered t o b e part o f a g eneral knowledge base. T hroughout c raft skills and experience a re u tilised t o a ssess which tools should b e employed a t a ny s tage o f t he p rocess, a nd h ow t hey should b e applied. The u se o f t ools, ( both material a nd c onceptual), i s a c rucial f actor s ince: their i nfluence o n the d irection o f work d one i s i mportant a nd f requently d ecisive. New t ools make possible the production o f entirely n ew s orts o f data I n i on

to

a nd

r elation the

i nformation t o

this,

phenomenon

( Ravetz P olanyi

whereby

6 4

1 971, ( 1958)

p eople

8 9-90). has

s killed

d rawn i n

t he

a ttentu se

o f

a c ertain tool or methodology a re unable t o s pecify i n d etail the skills they employ i n a ccomplishing a t ask. Having p erfected a n ew s kill many p rocedural elements become tacit, a nd a re undefined when the ' skill' i s t ransm itted t o a nother p erson, who may l earn the bulk o f these s kills by example ( Polanyi 1 958, 5 3). However, while d evel oping a n ew t ool or methodology i t i s much more l ikely t hat a greater p roportion o f the basic p repositions underl ying the approach t o the task w ill b e made explicit. H ence the i ntroduction o f a completely novel t ool p rovides a n i deal opportunity f or s ome o f t he t heoretical g round r ules implicit i n a s ubject t o surface i nto the consciousness o f t he d iscipline, a nd b e r e-examined a nd a ssessed. I t i s therefore v ery d isturbing t o note the r elative l ack o f d ebate amongst British f ield a rchaeologists o n where, why a nd h ow computers a re appropriate t o archaeological p robl ems. P articularly apparent i s a s ilent d isregard f or t he methodological, philosophical a nd ethical i mplications o f t he

d eployment o f

COMPUTERS

AS

c omputers w ithin

t he

p rofession.

ARCHAEOLOGICAL TOOLS

Computers a re not n ew to a rchaeology. Archaeologists have b een experimenting w ith these machines f or over a quarter o f a c entury. That their u se has had s ome i mpact i n a reas o f a rchaeological theory a nd p ractice has not gone unnoticed. For example, i n a ssessing a number o f computer based p rojects C henhall ( 1968, 1 7) asked "why the c omputer was

u sed;

whether

i t

should

have

b een"

and

p erhaps

most

i mportantly: whether anything c omputers which well

by

Subsequently,

s ome

was accomplished by the c ould n ot h ave b een d one

of a s

other means.

Whallon

( 1972,

Computer p rocessing o f a rchaeological manipulations t han o ther

u se j ust

3 0)

emphasised

t he

point

has l argely i nfluenced d ata by p ermitting more c ould ever b e achieved

t hat:

a nalysis c omplex i n any

way.

Additionally, s everal authorities s tress " the g enerally b eneficial effect o f exposure t o c omputers" ( Doran a nd Hodson 1 975, 3 46). Gaines ( 1984, 7 2) r einforces t his v iew when c ommenting t hat t he u se o f i nformation s ystems by American archaeologists during the l ast t en y ears has " increased t he n eed f or c larity a nd p recision i n t erms o f data and p rocedures." Both Gaines ( 1984) a nd Whallon ( 1972) a gree t hat i deas a nd approaches d erived f rom t he world o f computers a re f orcing a rchaeologists i nto n ew ways o f t hinking. Moreover, i t i s c lear t hat this experience contributed t o the p roduction o f much v aluable work, e specially t hrough a nalytical s tudies u sing c omputers. The

successful

application

6 5

o f

n ew

r esearch

t ools

a nd

methods normally encourages their further u se a nd d evelopment, thereby expanding t he theoretical f oundations o f t he subject. However, the effects o f the u se o f computers o n t heory, particularly i n f ield a rchaeology, go d eeper t han this. The implementation of analytical t echniques o ften r equires t hat specific data b ecome operational ( Watson, L eBlanc, and Redman 1 971, 1 14-21). This r esults not only i n a n eed f or g reater c larity a nd p recision i n d ata d efiniti on, but a lso means t hat the f orm o f the operational data r ecorded ( from t he raw o r p rimary d ata) i s c hanged. F ield a rchaeologists c annot a ssume that t hey a re s imply t ransferring f ossilised e lements o f past a ctivity i nto a n ew r ecord where they can b e further examined. I nstead elements a re s elected a nd then r emodelled t o s uit t he s tructure o f the medium o f s torage. Recently f ield a rchaeologists have b egun t o c hange over t o a s torage medium radically d ifferent f rom a nything p reviously available. A lready, s ome o f the s ide effects o f t his p henomena can b e d iscerned. For i nstance, P resland ( 1984, 7 ) s tates t hat: The implementation of a c omputer based r egister has a llowed, a nd i n s ome c ases n ecessitated, a number o f changes i n the types o f d ata r ecorded f rom a rchaeological s ites. This switch over t o computer s torage implies t hat changes s hould therefore b e made i n the r emodelling t echniques. A s a r esult, the c omposition a nd f orm o f the f inished r ecord may b e s ignificantly a ltered. I f s o, this may warrant a complete r econceptualisation o f the d efinable d ata c ategori es, e ntailing a r eassessment o f their epistemological s tatus. I t i s therefore i ncumbent o n those f ield a rchaeol ogists who employ computers t o b e aware o f t hese p roblems, and the extent t o which they themselves a re susceptible t o t hem. F ield archaeologists u sually have a r easonably c lear i dea of their i mmediate data-handling a nd a dministrative needs. Many have a l ess c lear notion t hat c omputers o ffer a p romising a lternative f or the s uccessful r ealisation o f these r equirements. Unfortunately, i t i s s eldom the c ase that a f ield a rchaeologist w ill b e s ufficiently well qualif ied t o a ssess the r elative merits a nd hazards o f u sing t hese machines. Richards' ( 1985) c all f or a ll a rchaeologi sts t o have some f ormal education i n the u se o f c omputers, m ight h elp a lleviate t his s ort of h andicap. I n t he meantime f ield archaeologists c ontinue t o b e lured by the c laims o f c omputer manufacturers i nto purchasing a machine. This t rend has b een c riticised by Voorrips ( 1984, 4 8) who h as h ighlighted many o f the r esultant p ractical d ifficulties and s tated t hat t his t rend not only p romotes bad computing p ractices but "probably p roduces b ad a rchaeology a s well..." Computers

o f

a ll

s hapes

a nd

6 6

s izes

a re

b eing

i r icorpor-

ated into many current projects, but it is the small busi­ ness machine which is becoming ubiquitous. The speed with which these machines are being introduced must indicate a belief in their archaeological utility. This display of confidence can perhaps be explained in terms of a widely held conviction that the new technology provides a means whereby British field archaeologists can wield greater powers of data management and analysis than has hitherto been possible. The prospect of such power is made more attractive given the structure and circumstances of British field archaeology and the current drive towards efficiency. It is hardly surprising that the uses to which field archaeologists are putting these machines reflects the bias of the available software; that is, database management, statistics and quantification, word processing and graph­ ics. This is not to suggest that archeologists should not explore the potential of these sources of software. On the contrary this practice has uncovered many useful packages and techniques which can be employed by archaeologists (see, for example, O'Neil 1984). However, computer techno­ logy is a tremendously versatile medium and in the long­ term archaeology would be better served by field archaeolo­ gists intimqtely familiar with the finer points of computer science. The remainder of this paper will enlarge upon some of the problems associated with just two controversial issues: standardisation and the application of artificial intelligence, particularly expert systems. STANDARDISATION

At present a multiplicity of commercially produced hardware and software is being employed in field archaeology. In reaction to this some people have argued for standardisat­ ion or at least compatibility. Some of those who support the notion of standardisation do not simply mean standardi­ sation in terms of hardware and software, but seem to believe that the general availability of computerised data­ base management systems will support the enforcement of data recording standards (Roberts 1980, Moorhouse 1985). Taken in conjunction with the advances in telecommunication this will facilitate the development of centralised resour­ ce centres, including databases and also software and hard­ ware facilities. However, one generally agreed benefit of setting up database systems is the way in which they force the data manager to think more clearly about the definit­ ion of data. The specification of one set of attributes implicitly acknowledges the existence of others. This rein­ forces a point that is clear from the history of archaeol­ ogy; - that is there is great variability to be found in archaeological data, and by looking at this data from different pe.I3pective, or by applying different tools and techniques archaeologists can produce significantly different types of information. This might argue against the imposition of standards from one level in an archaeological which may not be compatible with the successful hierarchy 67

implementation o f i ndividual policy d ecisions a d ifferent l evel, u sing d ifferent c riteria.

f ormulated

a t

Business p recedents may encourage the notion t hat c entralisation a nd s tandardisation, i f nothing else, make good economic s ense ( Cooper, this volume). I t could b e c ountered that a rchaeology i n Britain i s not y et a business and that these moves r epresent a f alse economy. C entralisa tion a nd s tandardisation h inder the p ractice o f a rchaeology i n t hat they mask the natural d iversity o f b oth the a rchaeological r ecord a nd r estrict t he i nterests o f t hose who r eveal i t: ' progress' i n the d iscipline c an only b e hampered by t hese p ractices which w ill p romote dogma a nd l imit

adaptability.

Contemporary economic a nd s ocial c onditions f oster the notion that f ield archaeologists, l ike other g roups t rying to maintain their p rofessional i ntegrity, have t o b e s een to b e ' efficient' by their paymasters. E fficiency i n modern f ield a rchaeology m eans, amongst other things, b eing able t o g ive the impression t hat f ield archaeologists a re able t o cope w ith t he v ast quantities o f data t hey u ncover i n the f ield, particularly i n t he course of excavation. Arguably, o ne o f the most c ost-effective means o f i mproving efficiency has b een t o f ormalise data c apture a nd handling p rocedures. P ro-forma data s heets p rovide o ne a lternative but i ncreasingly nowadays these c an b e r egarded a s a n i nter im m easure until a c omputerised s ystem b ecomes f easible. Computers s till h old a c ertain mystique. O ne o f their more dubious a ttractions i s that t hey a re b elieved t o enhance the owner's p restige. I n t his c ase, a computer i s l ittle more than a g immick c ontributing l ittle t o t he archaeological endeavour. Weizenbaum ( 1976, 3 4) has pointed out that s trengthening a t echnique by computerising i t a dds nothing i n i tself t o the t echnique's v alidity. Furthermore, c onsidering t he r ate o f d evelopments i n hardware a nd s oftware, a l ot o f material might b ecome r edundant when particular s ystems a re s uperceded. Against t his, computer t echnology p resents a m eans by with which data gathered a nd s tored i n o ne g eographical l ocation can b e t ransferred i n bulk t o a nother l ocation r elatively c heaply a nd quickly. There a re a lso s ome v ery good r easons f or wanting r ecords t o b e d irectly c omparable. For o ne t hing, while s ignificant d ifferences exist i n t he conventions of d ifferent r ecording s ystems, s earches t hrough successive data bases f or s pecific i nformation w ill b e more complicated i f s imiliar i tems a re c lassified i n s ignificantly d ifferent ways ( Gotlieb and Borodin 1 973, 2 5). I t h as t o b e a cknowledged t hat by a llowing f or t he possibility o f comparable r ecording s ystems b ased o n c omputers, u sers c an g ain a ccess t o a p otentially f ar g reater supply o f i nformation w ith which t o make comparat ive g eneralisations. The s ame move, h owever, c ould a lso

6 8

i nhibit r esearch i n o ther a reas a s well a s masking g enuine variability. D efining the f orm o f data categories expected t o b e r ecorded, i n a s ense, p re-empts the r ecording o f other r elated data a ttributes. I t might b e the c ase, f or example, t hat t he accurate r ecording o f two d ifferent data categories r equires the u se o f methods that a re mutually exclusive. O n the other hand, the v ery a ct o f f ocusing a ttention on o ne s et o f a ttributes i n a s ubject w ill d istract attention away f rom other, a nd p erhaps more i nteresting, f eatures. I n a ny event, f urther r esearch based on s uch data-sets, w ill b e constrained by methodological p rescripti ons that a re embedded i n t he i nitial categorisation p rocedures. This subtle canalisation o f theory a nd method exists a lready, b ut the c omputerisation o f data s ets w ill potentialy exacerbate the s ituation. I n many i nstances i t may not b e convenient o r p racticable t o modify data, b ec ause, f or example, the u ser does not have the ability o r t he s ystem i s too r igid t o s uit t he r equirements o f c ertain projects. S o, while the possibility o f p romoting c reativity i s a dvanced o n o ne t heoretical p lane i t may b e s tifled i n others. I n f ormalising r ecording s ystems, f ield a rchaeologists have, w ittingly o r not, s et s tandards. These s tandards may b e g eneralised a nd u sed i n o ther s ettings; when f ield archaeologists d o this they automatically allow f or the possibility o f making d irect c omparisons b etween what might otherwise b e i solated and particularistic data s ets. I t i s not d ifficult t o s ee why moves t o f ormalise d ata r ecording s ystems a re welcomed i n c ertain quarters. Taken t o i ts most extreme f orm s uch s tandardisation i s b elieved t o evolve i nto a mythical c reature k nown a s the universal database s ystem. The rapidly expanding c apacity o f c omputer s torage and s oftware d evelopments i n data management g ives c redence t o the c oncept o f g igantic database s ystems. The r eal a rchaeological i ssues a re c amouflaged a s a r esult. These c oncern t he nature o f t he policy d ecisions t hat have t o b e taken o n whether such g lobal type s trategies a re r ealistic o r d esirable. I n t he wake o f s uch questions, further p roblems arise i n d eciding what a re the most s uitable methods o f r ecording. B efore even approaching s uch questions a n extremely s ensitive i ssue would b e e stablishi ng which parties, i f a ny, a re e ntitled t o d ictate t he r equirements o f s uch a momentous d ecision a s s tandardi sation.

ARTIFICIAL I t i s i n c oncepts o f

I NTELLIGENCE AND

FIELD ARCHAEOLOGY

r elation t o the possible application o f the a rtificial i ntelligence ( A.I.), a nd i n p arti-

cular expert s ystems, t o f ield a rchaeology that the f unnell ing o f c reative a nalysis, outlined above, i s most apparent, f or h ere u sers a re c onditioned t o f ollow s et paths o f enquiry

d etermined

by

the

s ystem.

6 9

To

a n

even

g reater

extent

t han conventional database s ystems, expert control' of the material presented t o them.

s ystems

' take

With conventional database s ystems, t he u ser must know what t o a sk for and what t o d o w ith the r esults. A knowledge-base s ystem k eeps t rack o f t he meaning o f the data a nd p erforms i nferences t o d etermine what i nformation i s n eeded even when i t has not b een explicitly r equested ( Sowa 1 984, 2 77). Expert s ystems therefore r emove t he u ser f urther away f rom the raw o r primary data, making t he i nitial a ct o f d efini ng the data a nd t heir p otential r elations t o each other o f paramount importance. The p eople who come t o control this s tage of the d issemination o f knowledge occupy a v ery powerful position. So-called expert s ystems a re i n p rinciple v ery p owerful tools i ndeed: i n t heory they combine the ability o f a n expert with the massive memory c apacity o f a c omputer. Their u se, h owever, p resents their own s pecial p roblems. Hartley ( 1981) poses t he c rucial question o f who would constitute the b est domain consultants f or the s etting u p o f a computerised knowledge based s ystem, s uch a s a n expert system. Hartley makes a d istinction b etween " experts" a nd "practitioners" a s p ossible c andidates f or t he k nowledge consultancy i n a particular f ield o f s tudy. Experts c an b e characterised a s a m inority g roup t hat h as b een s ocially elevated i nto s tatus positions r elative to a b ody o f g enera l practitioners. I n the c onstruction o f a n expert s ystem i ncorporating a k nowledge base which i s f ragmentary, that i s, d ependent on s ets o f i ndividuals f amiliar w ith d ifferent s tocks o f a rchaeological d ata, p ractitioners would b e more appropriate a s c onsultants. The r eason f or t his i s t hat practitioners t end t o act s eparately; t hus h aving i ndividual experiences o f the d ifferent a spects a nd p otenti als o f the t otal data source, they would h ave "different knowledge". Experts a lso h ave t o r ely o n t heir own experiences, but even though t hey might h ave a much w ider experience than a ny s ingle p ractitioner, t hey c annot match t he aggregated experience of a l arge group o f p ractitioners. I f o n the other h and t he k nowledge base i s t hought t o b e s tructural o r systematic i n nature, then the experts a re l ikely t o b e t he b est c onsultants s ince " experts a re experts b ecause o f t heir ability t o s ee t he s tructure o f a domain and not merely i ts content" ( Hartley 1 981, 8 62) The above d ichotomy i s a nalogous t o t he c ontrasting v iews, expressed by members o f the A .I. c ommunity, o n the nature o f h uman i ntelligence; t he s o-called ' neat' a nd ' scruffy' v iews. The f ormer considers t hat a f ew elegant p rinciples u nderly a ll manifestations o f k nowledge. The l atter s ee knowledge a nd i ntelligence a s a "kludge", the accumulation o f many ad h oc approaches t o many d ifferent activities ( Sowa 1 984, 2 3). This r aises s uch questions a s: Which o f these v iews c haracterises a rchaeological knowl edge?

I s

t his

k nowledge

c hanging?

7 0

Archaeology i s a c raft-orientated d iscipline, not o nly i n the s ense t hat i t i s d ependent o n p ractical f ield work, but a lso b ecause i t r equires t he acquisition o f v arious s kills t o handle the material p roduced by this f ield work. The s ignificance o f the c raft a spects t o the d evelopment o f n ew knowledge h ave b een examined extensively b y P olanyi ( 1958), Kuhn ( 1970), Ravetz ( 1971) a nd Majone ( 1980). C raft k nowledge i s i mplicit t o a rchaeology a nd i s i nvolved i n a whole r epertoire o f p rocedures a nd j udgements t hat a re partly p ersonal a nd partly s ocial i n o rigin. For example, f ield a rchaeologists f requently have t o d ecide whether o r n ot particular data a re of a n acceptable quality, a nd i n making these t ypes o f d ecisions, s tandards have t o b e applied. These s tandards partly derive f rom i ndividual experience. They a lso r eflect norms i nstilled i n them by t he i ndividual's professional c olleagues and t eachers, a s w ell a s other culturally d etermined c riteria o f a dequacy ( Ravetz 1 971). The c riteria adopted c annot " conform t o abstract l ogical c anons", t hey a lso d epend o n c raftexperience, a s well a s the special f eatures o f the t ask b eing p erformed ( Majone 1 980, 1 53). The author does not s ubscribe t o t he b elief that a rchaeological d ata a re s omehow passive objects, o r j ust ' things i n themselves' waiting f or d iscovery. Nor i s i t l ikely t hat f ield a rchaeologists r ely o n s erendipity t o i solate the entities t hat t hey r ecognise and r ecord i n the c ourse o f their work. The material f ormations ' observed' a nd ' recorded' by f ield a rchaeologists a re not d irectly p erceived phenomena but c lasses o f i ntellectual c onstructs. Concepts l ike ' context' and ' association' a re u sed s o f requently that t here i s a t endency t o f orget t heir t heoret ical nature. The o bject o f a nalysis a nd policy, a s r epres ented i n a rchaeological r ecords, i s t herefore t heory-laden a s a r esult o f p rocesses o f d efinition, convent ' a bstraction. Anyone l ooking through the a rchaeological l iterature i s s truck by the s heer v ariety o f t echniques a nd l evels o f r ecording that h ave b een applied i n the past. This h eterog eneity r eflects not o nly the d iversity o f methodology but a lso the d ifferent degrees o f i ntuitive thinking that went i nto the making o f those r ecords. Such p roliferation o f i deas i s r egarded a s essential i f a n i ntellectual d iscipl ine i s t o r emain both h ealthy a nd v ital ( Feyerabend 1 975, 1 978). Archaeology i s a multifaceted d iscipline within which many sub-disciplines s uch a s c eramic a nd b one a nalys is have emerged. Each o f these s econdary s tudy g roups c an b e d ivided s till f urther a nd t here h ave d eveloped g roups w ith progressively more r estricted specialisations. I t i s i n these l atter g roups t hat a rchaeological ' experts' r eside, but naturally t hey c an a nd do operate a t s everal d ifferent l evels i n t he a rchaeological effort. I t s eems t hen t hat f ield a rchaeology i s p redominantly composed o f p ractitioners but i t a lso exhibits t raits c ommon t o Hartley's

s econd group o f

experts.

7 1

A key concept in expert systems is 'knowledge repre­ sentation'. This term, like several others used in A.I. parlance, is composed of words that are in common usage but in their novel setting take on new and not necessarily precise meanings (Newell 1982). A representation consists of a set of objects (or entities), known as the 'represent­ ed domain', and a set of relations known as the 'represent­ ing domain', together with a correspondence between them allowing questions asked of the represented domain to be answered by examining the representing domain (Palmer 1978; Kuipers 1979). The knowledge representation is therefore a dynamic model. Knowledge representations are created by 'knowledge engineers' who try to capture aspects of a real i world process. In particular these representations attempt to simulate what is thought to be the appropriate response of an expert to a particular situation, such as, the reaction of an archaeologist in assigning a date of production to a sherd of pottery. Moor, discussing the distinction between programs, theories, and models pointed out that: a computer model does not automatically embody a theory in the important sense that one knows what the theory is (1978, 221). He continues: even if there is some theory behind a model, it cannot be obtained by simply examining the computer program (op cit, 221-22). Thus it needs to be emphasised that the knowledge engineer's construct does not model the actual processes by which an expert arrives at a decision. It is designed to perform a number of operations which will result in a suitable response by th� system. How valid these models are will be dependant upon who is assessing them. So far questions relating to the episte­ mological, heuristic and metaphysical adequacy of these models with regard to archaeology have been rare, (Doran 1977 is an exception). Reliance is being placed on the standards of the world of artificial intelligence where the criteria of adequacy are largely those of engineers (McCarthy and Hayes 1969). Here, the existence of opposing schools of thought within the artificial intelligence frat­ ernity, concerning the underlying nature of knowledge, together with the dichotomy between "experts" and "practi­ tioners" indicate that it is in the interests of those domains hosting such systems to formulate and apply their own criteria of adequacy. Faced with the wide spectrum of opinion within A.I., reflecting the many different ways in which expert systems can be set up, caution in their use by field archaeologists cannot be overstressed. It is recommended that at present 72

t heir application i n a rchaeological s ituations b e r estricted t o experimental r esearch and not b e adopted uncritically f or r egular ' on-site' u se. B efore f ield a rchaeologists s tart employing expert systems i t i s imperative t hat the p rofession a s a whole i s aware o f t heir c onstruction, u se, l imitations and their probable effects o n the practice o f f ield a rchaeology. I t i s up t o a rchaeologists t o a ssess whether o r not the ' knowledge' built i nto these s ystems i s adequate f or a rchaeological n eeds. I f a rchaeologists a re t o b e capable of doing this, then t hey w ill n eed to understand h ow t his ' knowledge' i s s tored w ithin t he s ystem. They w ill a lso n eed t o know how i t i s manipulated once i n the s ystem, t o a ssess whether t hese manipulations a re a rchaeol ogically v alid. This means that a rchaeologists w ill have t o b ecome competent i n c omputer s cience. A rguments t hat a rchaeologists s hould confine themselves s olely t o archaeol ogical p roblems a re s hortsighted. Eventually changes i n the education curricula may produce a b ody o f p eople well g rounded i n c omputer t echnology a nd f ield a rchaeology a nd these p roblems w ill b e n eutralised. I n t he meantime there i s a danger that a rchaeologists w ill adopt s ystems d esigned by non-archaeologists who u se a rchaeology merely a s a t estb ed f or d eveloping a rtificial i ntelligence t echniques a nd not f or i nvestigating the nature o f a rchaeological knowl edge a nd how i t m ight b e r epresented i n i ts own r ight. At t he moment i t would b e f oolhardy t o p lace a ll our a rchaeol ogical eggs i n the knowledge e ngineers' baskets I f a rchaeologists b elieve that such systems c an b e p rofitably employed i n f ield a rchaeology then the o nus i s o n them t o demonstrate their s uitability. At a l ow l evel i t i s p ossible t o c heck that the s ystem i s f unctioning p roperl y s ince r eal experts can check them d irectly, but expert s ystems have two p roperties t hat make t hem p otentially d angerous once t he system has b een expanded. F irstly, l ike a ll computer s ystems they a re t otally s elf-validating a nd s econdly, they s uffer f rom a weakness common to any s ystem, a s

a : s ystem b ecomes more a nd more complex i t b ecomes i ncreasingly d ifficult t o v erify t hat t he model r epresents t he system accurately w ith r espect t o the p roperties under s tudy ( Gotlieb a nd Borodin 1 973, 1 11).

The i mplications o f these f eatures b ecome apparent when o ne examines the purposes t o which expert s ystems a re i ntended t o

b e

put.

Michie ( 1982, 1 97) has c haracterised three main modes i n which a n expert s ystem c an b e u sed: t he u ser a s a c lient, t he u ser a s a tutor and t he u ser a s a pupil. Each mode h as c ontroversial elements a ttached t o t hem. P olitical ed t o p lay environment

-

i ssues

a rise

when

expert

t he r ole o f a specialist f or example a c lay p ipe

7 3

systems

a re

employ-

i n a p rofessional s pecialist i n a n

archaeological unit. I f the u se o f expert s ystems w ere t o become v iable i n f ield archaeology i s i t conceivable t hat s uch a system might supplant the f ield a rchaeologist? A side f rom the ethical considerations the implications f or i ntell ectual activity i n t he a ffected a reas a re e normous. I f this were t o happen motivatation would undoubtedly s uffer. I n a v ery r eal a nd f undamental s ense a n expert system could quite easily b ecome a n authority f igure f or t hose obliged t o work w ith i t. The i ncentive t o b ecome proficient i n the r elevant expertise i s r emoved while l atent i nsights a nd novel observations w ill r emain s uppress ed. I n other words, t he work i s t ransformed f rom a potenti ally r ewarding a nd i ntellectually s timulating a ctivity i nto a mundane manual task. On the other hand a c ase might b e made f or their application i n o rder t o a lleviate t he burden of a n already mundane r epetitive task s uch a s a nalys ing c omplex s tratigraphic s equences. I n

principle

the

s econd of Michie's

u ser modes

could

h elp t o c ounter t his b u nkering effect, but t he f acility t o modify the knowledge base o f a n expert s ystem, b y alteri ng rule p remises o r adding additional d etails, p resents many p itfalls. Apart f rom the possibility o f entering s impl e f actual errors i nto the s ystem, ' polluted' i nformation could enter

the

s ystem b y

l ess

obvious

r outes.

For example, the s ituation may a rise where s everal u sers s eparated by g eographical d istance a nd p erhaps also t ime, obtain a n e stablished expert s ystem. G iven t hat i t i s i n the nature o f f ield a rchaeology t o p roduce ' new' evidence, the u ser, a s a tutor t o t he s ystem capable o f modifying i ts knowledge base i n order t o a ccomodate f resh material or to i ntroduce n ew r elationships, exposes s everal hazards. I n l ogical

t he data

r elevant

f irst p lace a vast amount o f p rimary i s d escriptive. Kuipers's ( 1979,397)

a rchaeoc aveat i s

h ere:

S ince

a d escription

c aptures

only c ertain

f acets

of

t he world, the s ame d escription c an h old o f s ituati ons t hat v ary i n the undescribed f acets. C onversel y, there c an a lso b e many d ifferent d escriptions o f t he s ame world, c apturing d ifferent f acets o f i t. As a s ystem g rows i t w ill b ecome i ncreasingly i mpracticable f or u sers t o a scertain whether o r not data h ave b een d efined t oo l oosely o r t oo c losely f or a p articular purpose. This could pave the way f or s uperfluous d ata c ategori es t o enter i nto t he s ystem o r a lternatively, two o r more data categories/attributes t hat s eparated might c ollapse i nto o ne. type

would

b e

compounded

over

Any a ttempt t o i ntegrate i ndependent l ocations would

7 4

could l egitimately I nconsistencies o f

b e t his

t ime. n ew ' knowledge' b e f raught with

a ssembled i n danger. The

b iggest p roblem, common t o a ll s ystems which r ely o n i ndependent s ources f or data-capture, i s that t he c omponent s ystems might employ s imiliar t erms which c arry quite d ifferent c onnotations d epending on their c ontext. I nstead o f building a n expert s ystem with g argantuan r ecall abiliti es, one s cenario f ollowing the w idespread u se o f t hese s ystems would b e a b efuddled automaton. Another i mportant question must b e how t he p rofession o f f ield a rchaeology c an maintain the i ntegrity o f i ts operational data i n s uch c ircumstances? This k ind o f probl em has a lways b een a common danger t o a rchaeologists working w ith t he material output o f others. I n t he past i ndividual i nvestigators were able t o exercise c ritical j udgement to r eveal a nd make a llowances f or ambiguous data. The scale o f the data s ets now b eing manipulated makes i t f ar harder t o c ritically appraise the bulk o f t he data s tored. This d evelopment i s most important t o t hose p rimari ly

c oncerned w ith The

third

u ser

quantitative mode

d efined

types

o f

a nalysis.

b y Michie

i s

o ne

where

the

user p lays the r ole o f a s tudent, by querying h ow o r why a decision c ame t o b e arrived a t. This i s p robably the l east d eveloped a spect o f expert s ystems. A basic f law c ommon t o a ll rule based s ystems i s that they c an only explain their c onclusions i n t erms o f the s tructure o f t heir k nowledge base, but they c an not j ustify why t his k nowledge was i ncorporated i nto the s ystem i n t he f irst p lace ( Clancy 1 983). This p roblem i s merely compounded b y appeals to c onceptually h igher l evel o r h euristic r ules which may a lso b e challenged. The t eaching mode l acks c ritical awareness: t he s ystem can n ot a ssess what c onstitutes a good o r bad question, a good o r bad a nswer, o r a g ood o r bad c riticism. Bad p ractice o n the part o f t he s tudent o f f ield a rchaeol ogy, therefore, would not b e r emedied by s uch a s ystem. As y et l ittle r eliance c an b e p laced on t he i nstructional v alue of expert s ystems, i n a rchaeology a t l east.

CONCLUSIONS This paper has a ttempted t o i ndicate s ome o f the ways i n which computer t echnology, especially s oftware, i s p roduci ng shifts of emphasis i n theory a nd method a nd s ome p otent ial p itfalls a ssociated with these moves. Currently t he majority o f f ield a rchaeologists do n ot even have a basic k nowledge o f h ow t o u se computers. A s y et, t he p rofession has not s anctioned t he a ctive e ncoura gement necessary t o d evelop t he r equired skills w ithin i ts membership. This i s r emiss f or whilst t his c ondition h olds f ield a rchaeologists must continue t o adapt t heir n eeds t o the available s oftware, ( and n ot t he c onverse which i s sometimes s tressed), which has normally b een d evel oped

f or The

other t rend

p urposes. t owards quantification

7 5

s eems,

i n

some

ways,

t o b e s ubsuming the qualitative a spects o f t he d iscipline. I n c ombination with l arger d ata s ets t his t rend i s i ncreasi ng the p robability o f i ntroducing p olluted d ata i nto d atabases. G iven t he ever g rowing c omplexity a nd c apacity o f i nformation systems i t i s b ecoming c orrespondingly d ifficult t o i solate a nd make a llowances f or ambiguous d ata. This problem i s v ery apparent i n t he d iscussion o f expert s ystems, the most s ophisticated d ata handling s ystems currently available. Expert systems r eveal many o f the h idden dangers o f t rying to i ntegrate data gathered b y d ifferent p eople f rom d ifferent sources. I t i s this t ype o f d evelopment t hat h eralds major d isturbances i n a rchaeologi cal p ractice especially i n connection with the f ormalisati on o f data a nd data p rocessing s tandards. The h istory o f archaeology r ecords the activities o f a number o f f ield a rchaeologists, each w ith t heir own i ndividual i nterests. Naturally the d ata-sets they p roduced were t o s ome extent s haped by the n ature o f t he questions they a sked and the methods they employed t o a nswer them. Thus the i nformation p rocured i s obviously value-shaped a nd therefore theory-laden. Archaeologists have consequently had t o d evelop many t ools w ith which t o extract i nformation f rom t he material o f others. I n making comparisons o r s yntheses, a rchaeologists may u tilise, c riticise, a nd even i gnore o r s imply f orget the work o f colleagues b oth past a nd p resent. A s methodology a nd t heory have d eveloped, l arge c hunks o f a rchaeological knowledge have b ecome r edundant o r l ost, a nd s everal t ools a nd t echniques have b een d iscarded. This type o f advancement may b e compared t o a Darwinian p rocess: t he survival o f t he f ittest or, i n t he c ase o f a rchaeology, survival o f the most f ashionable. The u se o f c omputer t echnology n eed not c hange t his. H owever, t he r amifications o f s tockpiling data derived f rom a multitude o f methodological a nd t heoretical approaches i n o ne o r More l arge i nformation systems a re v ery f ar r eaching i ndeed. This i s p articularly t rue i n s ystems t hat a re d escribed a s i ntelligent. I ncreases i n b oth data s torage c apacity a nd data handling ability advance t he g rowth o f a n ew c ycle o f d evelopment, s imiliar t o a L amarkian p rocess: t he i nheritance o f acquired c haracteristics. The l ife o f data c ollected i n one i ntellectual r n illieu i s b eing a rtific ially extended a nd p reserved. To d eal w ith t his f ield a rchaeologists w ill have t o d evise ways o f extracting and a ccounting f or a lien epistemologies embedded i n t heir databases. This r estructuring o f the n ature o f archaeological e nquiry m ight not b e wholly u ndesirable, but i t must a lways b e borne i n mind that computers a re not the s ort o f p alliat ive

t hat many

appear

t o b elieve

t hem

t o

b e:

i f a bad i dea i s t o b e converted i nto a g ood o ne, t he s ource o f i ts w eakness must b e d iscovered a nd r epaired. A p erson f alling i nto a manhole i s r arely h elped by making i t p ossible f or h im t o f all f aster o r more efficiently ( Weizenbaum 1 976, 3 5).

7 6

REFERENCES Chenhall,R. G. 1 968. "The impact of computers on archaeol ogical t heory: a n appraisal a nd projection", Computers a nd the Humanities, 3 ( 1), 1 5-24. Clancy, W.J. 1 983. "The epistemology of a rule-based expert system i n a f ramework for explanation", Artificial I ntelligence, 2 0 ( 3), 2 15-51. Doran,J.E. 1 977. i cal i nference",

"Knowledge r epresentation for archaeologMachine I ntelligence, 4 , 4 33-54.

Doran ‚ J.E. and Hodson ‚ F.R. 1 975. Mathematics a nd c omputers i n a rchaeology. Edinburgh University P ress, Edinburgh. Feyerabend,P. K. 1 975. a narchistic theory of -

1 978.

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Against m ethod: outline of knowledge. New L eft Books,

a f ree

society.

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a n London.

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London.

F indler,N. V.(ed.) 1979. Associative n etworks: r epresentat i on and the use o f knowledge by computers. Academic P ress, London. Gaines,S.

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American a rchaeology: a n overview o f Martlew,R. ( ed.), 1 984, 6 3-76. Gotlieb,C.C. computing.

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Hartley,R.T. 1 981. P roceedings o f the Artificial

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a spects o f c ognitive and L loyd,B.B. ( eds.),

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2 62-304. Polanyi,M. 1958. Paul, London.

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Presland,D. 1984. "A cautionary tale: computerization of the Victoria archaeological survey s ites", Advances i n Computer Archaeology, 1 , 7-11. Ravetz,J.R. 1 971. Scientific knowledge problems. Claredon P ress, Oxford.

and

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Richards,J.D. 1 985. "Training archaeologists t o u se c omputers", Archaeological Computing Newsletter, 2 ,

2 -5.

Roberts,D.A. 1 980. "Data s tandards f or A rchaeology", Microcomputers i n archaeology, M .D. A. Occasional paper Museum Documentation Association, Duxford.

4 ,

Rosch,E.H. and L loyd,B.B. 1 978. ( eds.) Cognition a nd categorization. Lawrence Erlbaum Associates, New J ersey. Sowa,J.F. 1 984. Conceptual s tructures: i nformation processing i n mind a nd machine. Addison-Wesley, London. Voorrips,A. 1 984. "Data catchment carrying capacity." i n Martlew,R.

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Watson,P.J., L eBlanc,S. A. a nd Redman,C.L. 1 971. Explanation i n a rchaeology: a n explicitly scientific approach. Columbia University

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7 8

COMPUTERS

I N

B RITISH ARCHAEOLOGY: NATIONAL STRATEGY

THE

NEED

FOR

A

Malcolm Cooper

After the a rchaeological h eritage i tself, t he most i mporta nt r esource a rchaeologists possess i s the data, o r i nforma tion concerning t he h eritage. The i ntroduction o f c omputers may b e s een a s a n important step t owards the efficient management o f t his r esource. There have, however, b een a s eries o f p roblems i n the a rea, b oth organisational and a rchaeological, which h ave meant t hat f rom a national v iewpoint we are s till a l ong way f rom the achievement o f this g oal. After a b rief s urvey o f the p resent a reas o f application i t i s i ntended t o concentrate o n the nature o f c omputer-usage i n f ield a rchaeology, l ooking a t t he problems i n more d etail and s uggesting methods o f overc oming them. At the p resent t ime, computers are u sed i n three o rganisationally d iscrete a reas of B ritish a rchaeology: excavation/post-excavation ( referred to a s ' field a rchaeolo gy' f or t he r est o f t his paper), a rchaeological r esearch, a nd cultural r esource management. Their application has gone hand-in-hand w ith t he ' information explosion' that occurred f rom the 1 960's onwards. The basic r easons f or t his s udden i ncrease i n the amount o f data a re w ell known, namely: a )

The

i ncreasing amount of

excavation

a nd

s urvey

i n

t his

country. b ) The i mprovement i n the a rchaeologists' u nderstanding the nature o f a rchaeological ' sites', l eading t o r ecognition o f more .e ntities i n n eed o f r ecording. c )

The

r efinement o f

d etailed

r ecording

o f

r ecording

t echniques,

l eading

o f the

t o more

each entity.

d ) The d evelopment and r efinement o f a nalytical t echniques i n b oth a rchaeology a nd t he s pecialist a reas, s uch a s environmental a rchaeology.

FIELD ARCHAEOLOGY The computer has b een employed a t a lmost every s tage o f the excavation a nd p ost-excavation p rocess. O n-site d ata capture i s b ecoming more common, due t o the c ontinuing r eduction o f s ize a nd i ncrease i n p ower, s torage a nd robustness of microcomputers. Hand-held ( highly portable) machines have b een u sed t o c apture d ata d irectly a t s ites such a s West Heslerton ( see P owlesland, this v olume), a nd i n other c ases d ata has b een t ransferred f rom t he r ecording sheets t o microcomputers s ituated i n t he f inds o r r ecording hut, a s occurred a t the D epartment o f Urban

7 9

A rchaeology's pers. comm.).

excavation

a t

Billingsgate

( Roskams,

P ost-excavation i s a n extremely t ime-consuming a nd r elatively expensive part o f a n excavation p rogramme. E ven i f data was not c aptured o n-site, a ll o r part o f the excavation r ecords m ight f requently b e t ransferred f rom paper to machine at a l ater stage, ( e.g. Booth, Brough a nd Pryor 1 984; Lock, t his v olume). This a llows advantage t o b e taken o f the extremely sophisticated data-base management s ystems available f or manipulation a nd basic a nalysis o f data. S imilarly, the employment o f a nalytical s oftware, whether o f a s tatistical or g raphical f orm h as b een s een a s r educing the cost o f the post excavation project, whilst i ncreasing i ts effectiveness ( see, f or example, Orton 1 981, F lude, George and Roskams 1 981). F inally, computers h ave b een u sed t o h elp p roduce excavation r eports and a rchives, a nd although there s ome problems t o b e overcome, i t s eems l ikely t hat excavation r eports will b e s ent t o publisher i n d isk i n t he f uture ( Sutton 1 984).

both are many f orm

RES EAR CH Turning t o the r esearch a rea o f a rchaeology, i t i s b ecoming i ncreasingly common f or i ndividual workers t o computerise specific data-sets f or a nalytical purposes. Statistical a nd multivariate software, d eveloped i n d isciplines s uch a s biology a nd medicine, has b een s uccessfully employed o n archaeological data ( Doran a nd Hodson 1 975, passim), and the application o f t echniques s uch a s s imulation and spatial a nalysis i n a rchaeology ( Hodder 1 978; H odder a nd Orton 1 976), has o ffered a v ariety o f new approaches f or t he modelling a nd understanding o f a rchaeological data. Archaeologists h ave also turned t o t he development o f s oftware specifically f or a rchaeological a nalysis, ( much o f which has b een d iscussed i n Computer Applications i n Archaeology, the p roceedings o f a n a nnual conference o n computer t echniques i n a rchaeology).

CULTURAL RESOURCE MANAGEMENT The computer i s also p laying a n i ncreasingly powerful r ole i n the administration o f t he a rchaeological r esource. I t has l ong b een r ealised that, i n o rder t o manage a nd protect t he n ational a rchaeological r esource, i t i s n ecessary t o have the i nformation concerning i t i n a r eadily accessible f orm a nd t hus w e have s een t he County S ites a nd Monuments r ecord f or many a reas b eing t ransferred o nto machine-based s ystems, ( see, f or example, Moffett 1 984; B enson 1 984). A r ecent survey has shown t hat s ome 2 5 SMR's had u se o f a c omputer a nd t hat d evelopment was i n p rogress i n o thers ( Inspectorate

o f

Ancient Monuments

8 0

1 984,

2 6).

S imilarly,

o n

a national scale, the schedule of ancient monuments is currently being transferred to a machine-based system (ibid, 1) and it is planned to increase the power of this system (ibid, 53). The National Monuments Record of the Royal Commission on Historical Monuments (England), has investigated the use of computers for holding its survey records (Fowler 1981, 109) and has implemented such a system for its 'excavation index'. The work of museums in the management of archaeological collections and archives should also be mentioned here, with many museums turning to computers for management purposes (Light 1984; Light and Roberts 1984). Altogether, over the past decade, we have seen a rapid transformation in the way in which archaeological data is captured, managed, analysed and distributed, with much credit being due to the archaeologists who have been far­ sighted enough to take advantage of the computerised system. Much of this transformation has taken place against the background of the technological innovation occurring in the computer industry, with the falling cost and increasing power of hardware, and the sophistication of many software packages, making the change a financially viable one. There seems little doubt that as developments in the computer world continue, so the machine-based system will play an ever-increasing role in archaeology. The overall potential seems to be very high, and yet a number of problems are becoming apparent, highlighting the conflict between effectiveness of the computer systems on the one hand, and current archaeological philosophies and method­ ologies on the other. For the rest of this paper I would like to concentrate on field archaeology, looking at the problems, both actual and potential, that need to be faced. In order to appreciate the background to the problems it is necessary to look at the organisation of field archaeology and the way in which this has affected the computer systems employed. Field archaeology at the present time has a highly decentralised structure. There is a measure of control from the main funding body, the Historic Buildings and Monuments Commission, in the coordination and implementation of an overall national strategy for excavation. However, most units have the staff and facilit­ ies to take an excavation from its planning stage through to publication, and may use techniques of excavation, recording and analysis which differ from those employed by neighbouring units. The introduction of the computer has tended to reflect this decentralised structure, not because it is necessarily the most beneficial one for archaeology as a whole, but because decisions determining implementat­ ion have been based on unit-level considerations alone. The overall picture for Britain is of the implementation of a large variety of hardware and software, this variety being based on a number of factors:

81

1 .

Funding

a nd

access.

Where i ndividual units d o not have the f unding available t o purchase c omputer s ystems they have o ften b een able to negotiate access t o hardware a nd s oftware f rom o ther organisations s uch a s u niversities o r c ounty councils. They a re therefore i n a n extremely l imited positi on when i t c omes t o c hoice o f h ardware a nd s oftware. 2 .

Guidelines.

Where f unding h as b een available f or t he u nit t o a fford i ts own system, t here has b een l ittle i n t he way o f guidelines c oncerning the ' best' hardware a nd s oftware f or archaeological applications. Although one v aluable a ttempt h as b een made ( Stewart 1 980), i t b ecame quickly outdated and there has b een l ittle i n t he way o f r eplacement. The r esult has b een t hat a more i nformal s ystem o f c hoice has b een employed with the s election b eing based u pon the p urchaser's own knowledge a nd p references, o r advice f rom v aried s ources, much o f which has come f rom outside the a rchaeological d iscipline. Additional variety c an r esult f rom d ifferential f unding b etween u nits, a ffecting the p rice range of the hardware a nd s oftware t o b e b ought. I n a ddition, where money has come f rom a l ocal authority o r c ounty c ouncil, a s tipulation may exist a s to the make o f computer t o b e purchased. 3 .

Technological

i nnovation.

As the computer i ndustry has advanced, s o units which have d elayed t he purchase o f c omputers have b een a ble t o take advantage o f the more r ecent d evelopments i n the f ield, turning away f rom s ystems a lready i n u se i n a rchaeol ogy t o ones which offer b etter f acilities. 4 .

A rchaeological methods, A s

there

i s

no

p riorities

national

a nd

g oals.

a rchaeological

strategy,

s o

methods a nd g oals vary b etween u nits, a nd t he p riorities which d etermine t he c hoice o f computers a nd s oftware thems elves 5 .

vary.

Archaeological

software.

The i nability o f p roprietry s oftware t o p erform t asks archaeologists r equire has l ed i ndividual u nits d evelop t heir own s oftware w ith l ittle r eference t o s oftware

w ritten

Although

by other

t here

a re

t he t o t he

units.

advantages

t o

s uch

a

d ecentralised

s tructure f or c omputers i n a rchaeology, a n umber o f s erious p roblems have b ecome evident which s uggest t hat t his particular structure may not b e t he most effective f or the c ountry 1 .

a s

a whole.

Nationally

there

i s

a s erious

8 2

i mbalance

i n

t he

i mplemen-

tation of computer s ystems, with some units u sing f or l arge amounts o f their work, a nd others f or amounts o r for none a t all.

s ystems s maller

2 . With the f unding f or c omputers b eing spread over a ll units i n a n u nsystematic manner and based o n y early p roject funding, i ndividual u nits have b een u nable t o a fford t he more powerful systems b etter s uited t o their work. 3 . With the spread o f f unding, i ndividual u nits a fford t o employ t rained computer professionals.

c an

r arely

4 . There i s a l ack o f s oftware f or a rchaeological a nalysis, and where i t has b een written by archaeologists i t t ends t o have b een a t ime-consuming operation a nd t he r esults a re rarely o f a professional s tandard i n t erms o f e fficiency, documentation a nd s upport. 5 . Due t o the l arge variations i n s oftware, hardware and p rogramming expertise i n a rchaeology, specifically written archaeological s oftware i s not easily t ransferable b etween o rganisations, a nd a rchaeologists rarely have t he t ime o r the i ncentive t o make i t s o. 6 . I t has not b een possible t o take advantage o f economies o f scale i n t erms o f bulk purchase o f hardware a nd multiu ser l icences f or s oftware. These problems a re multiplied when one i nvestigates the n ature of the a rchaeological entities t hemselves a nd the i nformation a rchaeologists r ecord c oncerning t hem. F irstly t here i s no s tandardised r ecording s ystem i n u se i n British a rchaeology today. This has meant that not only i s data f rom d iffering units t heoretically not c omparable, but that software d esigned t o handle and analyse data i n one u nit i s not d irectly . t ransferable t o a u nit w ith a d ifferent r ecording system. S econdly, the r eluctance o f a rchaeol ogists t o make explicit a nd t o publish their a nalytical methodology has l ed t o p roblems b oth i n the i nitial p rogramming of a nalyses a nd has a lso l ed t o t he c onstant r einvention o f a nalyses often i n a s lightly d iffering f orm. This process i s n ow b eing extended i nto t he p rogramming environment, with programs o f a s imilar nature b eing duplicated with a ll the t ime a nd e ffort t his e ntails. On balance t herefore, i t s eems t hat the organisational a nd f inancial s tructure which has d etermined t he f orm a nd u sage of computers i n British a rchaeology has b een h ighly u nsuitable f or t he optimisation o f efficiency a nd t hat despite the efforts o f a rchaeologists i n t his f ield, t he p resent methods o f i ntroduction o f hardware, t he d evelopment o f s oftware, and t he u ses t o which t he s ystems a re put, a re h ighly wasteful of r esources. F urthermore, t he existing systems f all f ar s hort o f the potential t hat c ould b e a chieved a nd may t hemselves c ause p roblems i n t he f uture d evelopment of the d iscipline.

8 3

The position i n which a rchaeology f inds i tself a t p resent, i n t erms of t he proliferation o f microcomputers t o manage the i nformation r esource, i s v ery s imilar t o the s ituation that many of the l arger c ompanies i n the business world h ave f aced i n r ecent y ears, although they have r eached a s imilar position by rather a d ifferent r oute. I n t heir case, the original Organisation o f computers t ended t o b e c entralised a round o ne o r a small number o f mainframe computers. A s t echnology i n t he computer world has i mproved, so branches o f t hese businesses b egan t o p urchase microcomputers for l ocal applications and, to f ight f or t heir own f acilities t o t ake over p rocessing f rom t he c entralised machine which was s low a nd d ivorced f rom t heir n eeds. This l ed i n many c ases t o a p roliferation o f a variety of microcomputers with the s ubsequent problems o f d istributing the i nformation r esource. To quote f rom K een a nd Woodman: p ersonal computers o ften p roduce a b andwagon effect. Many employees want o ne, but they may choose u nsuitable equipment a nd applications, a nd t hey may end up u sing their machines i neffectively o r hardly a t all o nce t he excitement wanes ( 1984, 1 43). Talking

o f

m icrocomputers,

t hey

s ay

I ronically, t his ease o f access i s posing complex p roblems f or managers i n many organisations. I ntroducing t hem i n o nes a nd twos can p roduce some s urprising r esults. F irst t here i s the t ime bomb o f i ncompatability. Every f orward l ooking i nformation s ystems manager f ears t hat t he whole w ill add u p t o l ess than the s um o f t he parts: a mishmash o f p rograms t hat w ill r un on o nly o ne v endors machine, the proliferation o f d ifferent databases, a nd c omplex p rocedures p lus add o n i nvestment to e nable particular micro-computers t o l ink u p with the mainframe computer ( 1984, 1 42). I t i s p ertinent a t t his point t o r emember t hat, i n the business world, bad management o f t he i nformation r esource often l eads t o a company's r elative i nefficiency a nd s ubsequent d emise a nd bankruptcy. There has b een, t hus, a spate o f l iterature concerning not only the b est methods o f s etting u p a c omputerised i nformation s ystem, but a lso i nvestigation o f the advantages a nd d isadvantages o f c entralisation a nd d ecentralisation o f c ontrol a nd f acili ties ( cf. King 1 983 and r eferences c ited) I f c omputer applications i n a rchaeology a re c onsidered on a n ational basis then much o f this l iterature i s h ighly r elevant a nd s hould not b e i gnored. .

I n s ummary, the authorities s tress t hat t he p roblems of implementing c omputer s ystems a re f ar more o rganisationa l t han t echnical. The main p oints t o come out o f the l iterature a re t he n eed f or l ong-term s trategic p lanning

8 4

f or

t he

i ntroduction

o f

c omputers

r ather

t han

s hort-term

t actical decisions, and the n eed f or the s trategy t o b e based upon a f ull u nderstanding o f the t echnology i tself, o f the goals o f business, and most importantly o f the s tructure of t he i nformation r esource i tself a nd t he way i t i s u sed to achieve these g oals. There i s no doubt t hat t here a re g reat weaknesses i n a ll these a reas i n f ield a rchaeology. S imilarly, a s f ield archaeology p rovides a l arge quantity o f the basic data f or b oth r esearch a nd c ultural r esource management, t his l ack o f s trategy must a ffect a ll a rchaeology. Although no f igures a re p resently available, further w eight f or t he f ormulation o f a national s trategy must c ome i f one endeavours t o e stimate the f inancial outlay made i n t he i nitial u sage o f c omputers i n British a rchaeology. I f w e say, f or the s ake o f a rgument, that t here i s a n i nitial s etting up c ost o f £ 5000 o n a m icrocomputer, s oftware, consumables and i nsurance, t hen t his may not r epresent a g reat r isk f or a s ingle f ield a rchaeology u nit, ( although i n the days o f project f unding, even this amount o f money h as b een hard t o r aise). I f, h owever, one multiplies t his by the number o f microcomputers n ow i n u se i n a rchaeology ( let u s s ay, f or t he s ake o f a rgument, 2 00) we a rrive a t a o ne million pound s etting up cost. Add t o this t he a nnual c ost o f the w riting a nd maintenance o f s oftware, s ystems d esign, etc., a nd o ne s ees t hat quite a s ubstantial sum of money i s b eing drawn i nto t he a rea o f c omputers a nd a rchaeology. At a t ime o f h igh f inancial p ressure o n a rchaeology, t he c ommitment o f such s ums w ithout a ny explicit s trategy must b e c onsidered surprising i ndeed.

A NATIONAL STRATEGY The s etting up o f a national s trategy i s by n o means a n easy task. Consideration must b e g iven b oth t o w hom s hould d evise the strategy, what f orm the s trategy should take, a nd h ow i t c ould b e i mplemented ( for o ne s olution i n t he business world s ee Withington 1 980, 1 61-3). There i s no d oubt that the d ecision-making b ody s hould b e broadly b ased a nd h ighly competent. Amongst the a reas s uch a body would n eed t o c over must b e: 1 . The s tudy o f t he existing British a rchaeology.

i mplementation

2 . The study o f the organisation o f t he i nformation r esource o n a n ational s cale. 3 . The establishment b oth s hort-term a nd g oals. 4 .

Sponsorship

s oftware, t he

o f

hardware,

c ompilation

o f

o f

computers

i n

archaeological

o f g oals f or a rchaeological computing, l ong-term, a nd t he o rdering o f t hese

d etailed

a nd

c omprehensive

communications a r ecommended

8 5

and

l ist

n etworks, f or

s tudies l eading

a rchaeologists.

o f t o

5 . the

The establishment of a c ode o f g ood p ractice purchase and u se o f h ardware a nd s oftware.

c oncerning

6 . L iaison w ith t he c omputer i ndustry i n o rder t o b ring a rchaeology t o the i ndustry's notice a s a c oherent d iscipline a nd thus t o s timulate i nterest i n a rchaeology. 7 . P romotion o f d evelopment o f computer t hrough both c onferences a nd publications. 8 . t he

The u se of a chievement

professionals o f goals.

9 . The development ment o f mechanisms

t he

computing world

f or

o f a p olicy s tatement and the e stablisht o b ring t ogether d iscordant i nterests.

1 0. The encouragement a t university and u nit

o f education l evel.

1 1. The encouragement o f a rchaeological computing. 1 2. i ng

f rom

applications

f or

c ooperation

The encouragement o f publication o n, c omputerised media.

archaeologists

b etween

through,

a ll

b oth

a reas

of

a nd a rchiv-

The r esult would b e a f ar more c oherent, efficient and effective a rchaeological i nformation s ystem based o n explicit goals and methods rather t han implicit, i neffici ent s hort-term s olutions t o p roblems o f a l ocal scale. A s a p art o f i ts work, the I nstitute o f F ield Archaeologists, t ogether w ith the RCHM(E) has s et up a ' Computer W orking P arty' t o i nvestigate t he present u sage o f computers i n British a rchaeology ( Institute o f F ield A rchaeologists 1 984, 2 1). This i n i tself must b e s een a s a r ealisation o f t he n eed f or a national v iew o f c omputers i n B ritish archaeology ‚ and i f the work i s not t o b e wasted, i t must b e s een a s the precursor t o a f ar more c arefully c ontrolled development o f computers i n archaeology t han i s t he c ase a t p resent.

FUTURE

I SSUES

When o ne l ooks t o f uture d evelopments i n a rchaeology, t here a re a number of a reas which could b e greatly a dvanced by t he application of t he c omputer, but s uch a dvancement w ill depend to a great extent upon the a rchaeologist's a bility t o c larify b oth t he a ims a nd t he m ethods o f the d iscipline. 1 .

Archives,

standardisation

a nd

databanks.

One o f the most i mportant a reas, d eserving o f c lose a ttention i s that o f t he nature, purpose a nd f orm o f the excavation a rchive. The b elief t hat excavation data i s o ne o f t he most important r esources i n archaeology i s not s upported by p resent t reatment. The ability t o c irculate

8 6

this data i n a u sable f orm has a lways b een r elatively p oor. The writers of excavation r eports i nclude s ubsets o f the data where t hey s upport t he g iven i nterpretation, but t he p ressure o f publication cost i nvariably means t hat other data i s not i ncluded ( residual material f rom u rban excavati ons, for example, i s rarely d iscussed). Data not i ncluded i n the published r eport i s u sually a ssigned t o s ome f orm o f paper archive which i s i n such a f orm a s t o b e r elatively u nusable without c onsiderable effort o n the part o f s ubsequent r esearchers, both to l ocate i t a nd then t o u nderstand i t i n t erms o f t he excavation p hilosophy, the r ecording philosophy and the a nalytical methodology o f the o riginal excavators. The p resent d ebate i n publication has h ighlighted the f act that under t he p resent f inancial r estrictions, l ess and l ess data i s appearing i n the excavation r eports. I n other words, a rchaeologists' only method o f c irculating t he basic data s ets o f the s ubject i s b eing eroded. This d evelopment, when c ombined w ith t he p hilosophy ( expressed, f or example, i n the ' Cunliffe r eport' CBA/DOE 1 982) t hat o nly the ' basic' r esearch should b e done o n excavation, l eads u s i nto the unacceptable position o f b oth d iscouragi ng r esearch o n excavation, while a t t he s ame t ime d iscouraging r esearch outside excavation a nd making i t l ess e ffective. One v ery a ttractive solution t o this p roblem i s the c reation o f a c omputerised n ational excavation d atabank, to b e u sed both t o house t he a rchive f rom excavations, and more i mportantly t o act a s a basis f or s ubsequent a rchaeol ogical r esearch, providing data-sets i n machine r eadable f orm. The cost o f such a v enture would not b e h igh i f spread across British archaeology a s a whole and t he advant ages f or the s olution o f p resent a rchaeological p roblems could b e very h igh. The concept o f a c entralised databank f or a rchaeological data i s not a n ew o ne ( cf. Chenhall 1 971) and much has b een l earned c oncerning t heir s trengths a nd weaknesses ( cf. Chenhall 1 981; Gaines 1 984). However, t he v iability o f a databank a nd i nformation s ystem f or excavation data w ill depend greatly upon whether t he t rend i n excavation r ecording i s t owards s tandardisation or away f rom i t. P erhaps most

i mportant,

the

o rganisation must

speak

a common l anguage. Any i nformation t o b e c ommunica ted b etween nodes i n t he n etwork must b e precisely d efined s o that the s oftware a t a ll the nodes w ill b e able t o p rocess t he d ata r eceived ( Withington 1 980, 1 57). As a lready mentioned, a t t he p resent t ime t here i s a w ide variety o f r ecording systems i n u se i n B ritish a rchaeology. The r easons f or s uch v ariety a re n ot obvious, but i nclude the d ecentralisation o f excavation units ( each b eing allowed a f ree-hand t o d evelop t heir own s ystem), t he w ide

variety

o f

s ites

under

8 7

excavation,

a nd

v arying

conceptions o f the nature o f archaeological entities. I t has b een a rgued t hat the i ntroduction o f s tandardisation can l ead t o a fossilisation o f a d iscipline ( see Richards, t his v olume). Whilst t here i s s ome t ruth i n s uch a rguments, there a re also p roblems i f a l arge number of r ecording s ystems a re allowed t o d evelop i n i solation. The f irst p roblem r elates t o t he possibility t hat, b eneath t he variety o f t erms a nd s ystems, i n many c ases t he same data i s b eing r ecorded i n a s imilar f ashion. I f this i s the c ase, t hen i t i s h ighly wasteful i n t erms o f t he opportunities l ost f or explicit d ata d efinition and comparison. Standardisation, i n t hese c ircumstances, c an only b e considered advantageous. The s econd p roblem i s t hat i mportant d ifferences i n t he p erceptions of a rchaeological entities a re b eing d isguised by t he "variety f or variety's s ake" r ecording practice. Unless a ttempts a t s tandardisation are made, s uch meaningful d ifferences c annot b e r eadily i dentified, r eceive l ittle publicity and t hus c annot b e exploited. The long overdue r eview o f excavation r ecording systems i n this country may well occur through the a dvent o f c omputer t echnology a nd t he i nvestigation of databanks i n a rchaeology. I f any solution i s l ikely i t w ill p robably b e through a c ombination of the i dentification o f a ' hardcore' o r ' basic' data s et which i s r ecorded i n a s tandardi sed f ashion across t he c ountry ( based upon a s tudy o f t he present f orms o f r ecording systems) a nd a n a dditional c lass o f r ecorded data which c an b e i mplemented o n a purely l ocal scale and may, i f s uccessful, b ecome i ntegrated i nto t he ' hard-core' at a l ater s tage. Such i dentification would g o hand-in-hand with the compilation of k eywords and thesauri. The hard-core would t hen a ct both a s a n explicit s tatement of the s tage r eached by a rchaeological r ecording, a nd a s a base f or a national a rchive a nd i nformation s ystem. S tanda rdisation without o ssification has b een achieved i n t he business world ( Withington 1 980, 1 53-4) a nd there s eem t o b e great possibilities i n t he i ntroduction of a f lexible s ystem f or f ield a rchaeology i n Britain. 2 .

Analysis.

One o f the g reatest p roblems f acing f ield a rchaeology i n t his country i s t he unwillingness o f excavators t o publish t he a nalytical m ethodology o n which t he i nterpretation o f a s ite l ies. This has meant that not only has a c ertain amount o f r einvention t aken p lace i n methodology, but t hat i t has b ecome hard t o appreciate the a reas i n which a computer m ight b e u sefully employed. I t would therefore b e of great v alue t o i dentify the ' standard' exercises a nd a nalyses u sed o n excavation which a re amenable to computerisation ( such a s s tratigraphy d iagrams, a nd d istribution p lots) a nd t o encourage t he d evelopment o f t he appropriate software ( if n ecessary, commissioned p rofessi onally)

to

b e

s upplied

t o

a ll

8 8

excavations

o n

r equest.

This

m ight a lso i nclude database possibilities o f multi-user l ittle explored. 3 .

C entralised

management s oftware, l icenses f or s oftware

w here t he h ave b een

S ervice.

I n c ombination with 1 . a nd 2 . a bove, c onsiderable t hought should b e g iven t o t he c reation o f a c entralised c omputer s ervice, whose f unction would b e t o o ffer a w ide v ariety o f computer-based a nalyses f or data-sets s ent i n f rom excavations which d id not h ave t he n ecessary expertise o r c ould not a fford t o purchase the n ecessary hardware o r s oftware, but which c ould a fford to pay f or i ndividual a nalyses. The b enefits o f spreading t he costs o f expensive h ardware a nd s oftware over a rchaeology nationally c ould quickly b e r ealised, together with the opportunity t o offer a c onsultancy s ervice f or a rchaeologists.

CONCLUSION I t may b e a rgued that British a rchaeology has r eached a point where i t i s n ecessary t o examine the f uture r ole o f t he c omputer i n g reat d etail. A lthough, i n the n ame o f philosophical purity, i t may b e advantageous t o l et the p resent c haotic d evelopments c ontinue, i f a rchaeology i n t his country i s envisaged a s a business, then s uch economic c oncepts a s opportunity c ost have a n a ll t oo r eal m eaning. I t w ill p erhaps b ecome n ecessary t o sacrifice s ome i ndividual f reedom i n a rchaeology i n o rder t hat t he d iscipline may r eap t he potentially l arge b enefits t hat could b e achieved by s uch a d evelopment. However, the f uture o f c omputers i n a rchaeology should b e based on a n explicit a nd l ong t erm s trategy, rather t han i mplicit a nd r andom d evelopments. There s eems l ittle doubt a lso t hat the f ast d evelopment . o f c omputers has h ighlighted underdeveloped a reas i n a rchaeological t heory a nd methodology. The c ase f or a s tandardised hard-core o f excavation r ecording i s i n d esperate n eed o f attention, a s i s the n eed f or the a iring o f excavation a nalysis methodology. Such p roblems w ill d etermine the speed and effectiveness o f computer i mplement ation i n a rchaeology a nd t he overall f orm o f t he s ystems i n u se. One o f the l argest p roblems t o b e f aced i s t he i dentifi cation o f where t he r esponsibility f or implementing a n ational s trategy l ies. The d ivision of r oles a nd f unctions b etween the H BMC and the RCHM(E) has r esulted i n n either b ody b eing i n t he most effective p osition t o d etermine t he d evelopment of computers i n a rchaeology. I t s eems l ikely t hat t he p resent r ole o f t he National Monuments Record, i n minding excavation a rchives, w ill l ead t o the i nvestigation o f s tandardisation o f r ecording a nd methods o f machinebased i nformation handling a nd communications. H owever, i t s eems l ikely t hat f or such a p lan t o s ucceed, t he H BMC a s t he

main

f unding

b ody

i n

a rchaeology,

8 9

would

have

t o

g ive

active encouragement t o such work, helping t o achieve agreed s tandards a nd i nvestigating such possibilities a s the c entralised computing s ervice. Overall, the c omputer o ffers t he a rchaeologist many possibilities, these b ecoming more tempting with each y ear's developments i n the computer world. Our choice t oday will undoubtedly affect the archaeology of tomorrow a nd the r esponsibility l ies f irmly w ith u s t o d etermine t he d irecti on to b e taken. However, when making such a decision A llen g ives p ertinent advice: . many

businesses

today

face

problems

i n

their

u se

of our wonderful t echnology s o s erious t hat t hey threaten t o j eopardize [ their] b right future.... K ey to [ the] s olutions i s t he f ormulation o f comprehensive strategy f or the d eployment o f i nformation r esources w ithin t he c ompany ( Allen 1 982, 7 7).

REFERENCES

Allen,B. 1 982. d ead", Harvard

"An unmanaged computer system Business Review, 6 0, 7 7-87.

can

s top

y ou

Booth,B. ,, Brough,R. a nd P ryor,F. 1 984. "The f lexible storage of s ite data: a microcomputer application", Journal of Archaeological Science, 1 1, 8 1-9. Chenhall,R.G. 1 971. "The archaeological data bank: a p rogress r eport", Computers a nd the Humanities, 5 ( 3), 6 9. 1 981. "Computerised data bank management", Gaines,S.W. ( ed.), 1 981, 1-8. -

CBA/DOE 1 982. The excavations. CBA,

publication London.

of

1 59-

I n

archaeological

Doran,J.E. and Hodson,F.R. 1 975. Mathematics a nd c omputers i n a rchaeology. Edinburgh University P ress, Edinburgh. F lude,K., George,S. and Roskams,S. 1 981. " Uses of a n a rchaeological database w ith particular r eference t o computer graphics and the writing-up p rocess", Computer Applications i n Archaeology, 1 981, 5 1-60. University o f London. -

Fowler,P.J. 1 981. "The Royal Commission o n H istorical Monuments ( England)", A ntiquity, 5 5, 1 06-14. Gaines,S.W. ( ed.) 1 981. Data bank applications archaeology. University of Arizona P ress, Tucson. -

1 984.

"The

impact

of

computerised

9 0

systems

on

i n

Ame r ican

a rchaeology: ( ed.), 1 984, Hodder,I. Cambridge

an overview o f 6 3-76.

the

past

decade",

( ed.) 1 978. S imulation studies University P ress, Cambridge.

Hodder,I. and Orton,C. a rchaeology. Cambridge

i n

i n

Martlew,R.

archaeology.

1 976. Spatial analysis i n University P ress, Cambridge.

I nspectorate o f Ancient Monuments a rchaeological r esource.

1984.

England' s

I nstitute

1984.

Annual

o f

F ield Archaeologists

Keen,P. G.W. and Woodman,L. A. 1 984. "What t o t hose micros", Harvard Business Review, 6 2,

Report

do with 1 42-50.

No.1.

all

King,J.L. 1 983. "Centralised v ersus decentralised computing: organisational considerations and management options", Computing Surveys, 1 5 ( 4), 3 19-49. Light,R. B.

1 984.

Applications Birmingham.

i n

"Microcomputers A rchaeology,

i n

1984,

museums", 3 3-7.

Computer

University of

L ight,R.B. and Roberts,D. A. 1 984. Microcomputers i n museums. Museum Documentation Association Occasional 7 , Duxford, Cambs.

P aper

Martlew,R. ( ed.) 1 984. I nformation s ystems i n a rchaeology. New Standard Archaeology, Alan Sutton, Gloucester. Moffett,J.C. 1 984. "The Bedfordshire County s ites and monuments r ecord database management s ystem", Computer Applications i n A rchaeology, 1 984, 1 01-9. Orton,C. 1 981. "Cheam: a computer-assisted s tudy o f the pottery f rom a mediaeval k iln s ite", Computer Applications i n Archaeology, 1 981, 9 5-100. University o f London. Stewart,J.D. ( ed) 1 980. Microcomputers i n a rchaeology. Museum Documentation Association Occasional Paper 4 , Duxford, Cambs. Sutton,A. ( ed.),

1 984.

1 984,

"Cost-effective

publishing",

i n

Martlew,R.

1 15-25.

Withington,F. G. 1 980. "Coping with computer Harvard Business Review, 5 8, 1 52-64.

9 1

p roliferation",

STANDARDISING THE RECORD Julian Richards

I NTRODUCT I ON I t i s commonly s tated t hat standardisation of data-handling p rocedures i s a d esirable a im. To this i s f requently added a s econd a im o f p roducing a u niversal g eneral-purpose data bank f or a ll a rchaeological k nowledge. This paper w ill question these v iews a s they may otherwise b ecome accepted a s the " conventional w isdom" without f urther d iscussion. I s hall a rgue that standardisation i s not worth the effort, and i ndeed, t hat i t may b e positively harmful t o t he future d evelopment of a rchaeology, f or i t i s l ikely to constrain questioning and thought. Archaeological knowledge i s not y et a t a s tage when variables a nd c lasses o f data c an b e defined which w ill hold f or all t ime. Furthermore, t he mechanical c ollection of data according t o p redetermined categories i s contrary to a hypothesis-testing approach, a nd u ltimately r educes t he a rchaeologist t o the l evel of t he t echnician. We a re i n danger of b ecoming u nrealistic i n our p redictions of what the computer can do f or u s. Actual data banks a re confused with their s cience-fiction counterparts, a nd are s een a s having vast i nformation p rocessing and r etrieval capabilities. There i s a s chool o f thought that s eems to b elieve that i f only we could computerise a ll our excavation r ecords, s ites a nd monuments i ndexes, or museum a rchives, then a ll our p roblems would b e over. We n eed only p ress a button, a nd out would magically appear " The Answer" I am totally convinced of the b enefits t o b e gained from the application of c omputers t o a rchaeological r esearch. I take i t f or g ranted t hat computers should b e u sed, a nd will not a rgue t hat case. H owever, the i dea of the all-powerful computer, once u seful a s a s elling point t o convince r eluctant a rchaeologists t o embark on a procedure which was alien t o t hem, i s i n danger of b ecoming a myth. A s Shetler, a b iologist, has a rgued, s uch myths: actually obstruct p rogress by f alsely r epresenting t he goals t hat r ealistically a re a ttainable a nd t he obstacles t hat must b e overcome t o a ttain t hem ( 1974, 7 3).

P ROBLEMS OF STANDARDISATION S tandardisation i ncorporates a t i ssues: compatability of computer i on of data. The

f irst

i s

the

question

9 3

of

l east two v ery d ifferent s ystem, a nd s tandardisat-

which machine

a nd operat-

ing system should be used. It is argued that if all users could be persuaded to use the same hardware, operating systems, and programming languages, or at least ones which are compatible, then a great deal of duplication of effort could be avoided. I accept that this is a very desirable aim, but think it is somewhat of a red herring. Information technology is still developing at such a rate that if we were to attempt to define standard equipment, in a few years time we would be likely to find that it was outmoded. Precisely this has happened to one proposed standard. A few years ago a Museum Documentation Association seminar on micro-computers in archaeology recommended a draft standard consisting of a Z80-based micro such as the RML380Z, with 8" discs, and running CP/M (Stewart 1980). It was admitted then that: A standard cannot live for ever, and an attempt at standardisation now must not be seen as an attempt to delay the introduction of new hardware and soft­ ware as it becomes available (Graham 1980, 47).

Indeed, 8" discs are virtually obsolete, the Z80 has been superseded by 16 and even 32 bit processors, CP/M by CP/M 86 and MS-DOS, and even the Research Machines 380Z is looking a bit steam-powered. It would be similarly futile to try to propose a standard today. Eventually, standardisation of hardware will be achieved, but it will be as a result of market forces, and there will be nothing that archaeologists can do about it. Already the entry of the computer multi­ nationals into the micro-computer market is laying down certain standards, and the words "IBM-compatible" now appear in many micro-computer advertisements. In the meantime·, the question of compatability should be approached from the view of standard high-level langu­ ages, and communication facilities. Programs and data can be exchanged by a variety of means other than discs (see Richards and Ryan 1985, 52-3). So long as programs are designed so that they have the facility to produce some form of standard output file, then the problem of communi­ cation between archaeologists is over-estimated. The main difficulty is in the exchange of programs written in different dialects, rather than in the exchange of data. Fears about lack of standardisation often seem to presume that there is a great demand for exchanging data amongst archaeologists, which seems doubtful on the basis of past history. Archaeologists usually want the products of each others research, not the raw data. The excavation report or county survey becomes the authoritat­ ive starting point for future research. This is unlikely to change. The second issue which comes under the general heading 94

o f s tandardisation i s that of s tandardisation o f data banks. This means that s tandards should b e d efined, i n particular, f or t he f ields and s ets o f k eywords i n u se i n excavation r ecording and county s ites a nd monuments r ecords. This i mplies that every excavation u nit s hould eventually u se t he same r ecording s ystem, a nd every county t he same SMR system. These r ecords could then b e t ransferr ed t o some c entral l ocation to p rovide a national a rchaeol ogical data bank, i n which r ecords f or i ndividual excavati ons a re conceived a s part o f s ome massive h ierarchical data s tructure. P leas f or s tandardisation o f excavation r ecording f requently a ssume t hat data would t hen b ecome c omparable ( see e .g. d eere 1 984, 1 6; Gaines 1 984, 7 3). The Central Excavation Unit system i s most f requently mentioned a s the o ne to b e adopted, a nd could b e f orced o n a ll archaeologists i f f unding f or the d evelopment o f a lternati ves i s w ithheld. At the SMR l evel, i n t he mid-1970's a working party was established t o study a rchaeological r ecords f or the Royal Commission on Historical Monuments ( England). I ts r eport ( RCHM(E) 1 975) r ecommended the establishment o f a National Non-Intensive S ites and Monuments Record, c overing l ocation, administration d etails, s ite d escription a nd b ibliography. A more l imited computerised i ndex i s b eing c ompiled, noting a ll excavations a nd the l ocation o f a ll a rchives a nd f inds. To date 1 0 counties have b een f ed i nto t he computer system, and: When complete, t he database w ill consist o f a n estimated 3 0-40000 entries a nd will p rovide not only a gazetteer of the h istory o f archaeological excavation i n this country, but also a comprehensive r egister d etailing the l ocation o f all r etrievable a rchives a nd f inds ( RCHM(E) publicity handout 1 984). Yet the c hairman of t he working party has r ecently s tated t hat: I now r ealise t hat t he content of the p roposed National Non-Intensive Record was i nadequate f or r esearch a nd was, moreover, duplicated i n much more d etail a t County l evel ( Cleere 1 984, 1 3). However, rather t han abandoning the p roject, d eere r ecommends the i ntroduction of more data on excavation y ields, dating, a nd b ibliographical material, a lthough s topping s hort

o f

a " super

database".

We s hould b e aware t hat others h ave already b een down the road on which we a re t ravelling. I n the United S tates i n t he m id-1960's t here was much t alk o f s etting u p a g eneral-purpose u niversal a rchaeological data bank. Robert Chenhall was amongst t he most a ctive p roponents. I n 1 968 h e t alked euphorically o f: t he possibilities t hat w ill open up when a rchaeol ogists f inally decide to f orgo their i diosyncratic

9 5

a nd parochial typologies data bank ( 1968, 2 2).

f or

a more

n early u niversal

I n 1 971 h e r eported o n the progress made t owards t he universal data bank ( Chenhall 1 971). There were t hree main d ifficulties. F irstly, computer hardware a nd s oftware were then only j ust adequate f or t he project. S econdly, o rganisational facilities were not a vailable to s upport a ny k ind of consistent and u nified p roject. A r id t hirdly, a rchaeological t heory was so i ll-defined t hat no one could s ay with a ssurance what should b e r ecorded i n a data bank. Of these i t i s the third that i s s till crucial. The f irst two problems h ave b een solved, both i n the United S tates a nd i n t he British I sles. W ith the d ecreasi ng cost of computer memory t he t echnology i s now c apable o f s toring a nd r etrieving masses o f i nformation a t v ery h igh speeds. State o r c ounty archaeological units c an p rovide the organisational support. H owever, there i s no more agreement about the data t hat a rchaeologists should r ecord than there was i n 1 971. Nor i s i t a dvisable t hat there should b e. Minimal units of observation a re not i nherent i n t he data. Data does not exist i n the ground, i ndependent of the a rchaeologist. Data i s d iscovered, o r even i nvented, by t he a rchaeologist. What i s r ecorded w ill b e a p roduct p artly of s ome accepted wisdom of what should b e r ecorded, a nd partly the r esult of the particular r esearch a ims o f t he p roject. These will vary according t o the c hanging i nterests o f archaeologists, a nd t hat i s r ight a nd p roper, a nd l eads to a h ealthy d iscipline which c hanges t o k eep pace w ith the i nterests of the t imes. T here s eeking t o

a re a t i mpose

l east t hree d ifficulties h ere, i f a g eneralised r ecording s tructure.

o ne

i s

F irstly, excavation, r ecording, a nd i nterpretation a re s ubjective p rocesses, a nd no amount of computerisation c hanges that. I f even two a rchaeologists c annot a gree when a s take-hole b ecomes a post-hole, o r when a s ilty-sandy c lay b ecomes a s andy-silty c lay, then i t i s Utopian t o suppose t hat the a rchaeological community a s a whole might a gree. The use of s tandard t erms t hroughout the c ountry, when a York post-hole might b e d ifferent f rom a Southampton post-hole, i s dangerous a s i t m ight l ead to f alse c onfidenc e i n the comparability o f data. I f data i s ever t o b e c omparable t hen f irst s ome radical s tandardisation w ill have t o b e carried out a t t he excavation stage. S econdly, s tandardisation would n ot a ctually b e b eneficial t o the f uture o f archaeology. Advances i n a rchaeological k nowledge f requently c ome a bout t hrough p eople d iscovering n ew c lasses of d ata t o r ecord, t he a nalysis o f which p roduces s ignificant r esults. Were a rchaeologists t o adopt a s tandardised t here would b e no i ncentive t o t hink

9 6

r ecording s ystem, o f n ew ways o f

excavating a nd r ecording s ites, a nd no new data would b e p roduced. This comes back t o the f irst point, f or s ince a ny r ecording s ystem i s t he p roduct of the particular i nterests o f the p eople who designed i t, a nd the concerns o f t hat age, a fter s everal y ears o f u se we s hould either s till b e t rying to a nswer the old questions a nd t here would b e no advance of knowledge, o r we s hould b e r ecording data which was i nappropriate t o current r esearch a ims. The third danger i s of a more practical, but f ar f rom t rivial nature. Having adopted a s tandardised r ecording s ystem, the a rchaeologist b ecomes a t echnician, rather than a thinking excavator. H e or she mechanically f ills i n boxes, or p resses keys according to p re-determined s ets of rules. The consequences f or the a rchaeological p rofession a re a larming. I n t he United States, these problems were swiftly r ealised a nd i t may b e worth l ooking a t t he d evelopment o f data-banking t here. The A rkansas Archaeological Survey was put f orward a s a model o f how g eneral-purpose data banking s hould p roceed ( Chenhall 1 971). A l etter written t o t he editor of t he j ournal C omputers a nd the H umanities commented: Different a reas o f t he c ountry a sk d ifferent questi ons of their data a nd have d ifferent n eeds a nd expectations. These d ifferences should b e r eflected i n their c omputer programs. The A rkansas p rogram i s v ery f lexible i n t hat i t w ill accept a ll k inds o f data, but i t a lso r eflects the type o f i nformation which archaeologists i n Arkansas d eem s ignificant ( Schneider 1 971, 2 41). Robert Whallon

warned

that:

data banking done t oo s oon a nd on t oo a ll-encompassi ng a scale i s not l ikely t o p rove particularly u seful t o i nnovative, experimentative, a nd exploratory r esearches a nd may actually t end t o s tifle active questioning a nd thought ( 1972, 3 8). The o riginal proponents of the universal data bank a t f irst a ttempted a compromise by i ncorporating f ields which a nswered specific r esearch questions within t heir g eneralpurpose data-bank. H owever, i t was s oon r ealised that i t was impossible t o r ecord data f or every possible a nalytical c ontingency. I n 1 976, even Chenhall was f orced t o a dmit that: I n s ummary we f eel that a g eneral purpose data b ank i s of l imited r esearch u tility, a nd i t i s therefore d ifficult t o j ustify l arge s ums o f money, energy, a nd t ime b eing spent o n non purpose-orientated computerization o f ( Scholtz a nd Chenhall

a rchaeological 1 976, 9 5).

9 7

i nformation

The c onclusion f rom the American experience was t hat l arge computerised data banks m ight continue u sefully a s c ataloging s ystems, w ith a minimum o f descriptive i nformati on, but t hat i ndividualised special-purpose data banks would c ontinue to be u sed f or t he a nalysis o f d ata. I n British a rchaeology, Doran a nd Hodson concluded that: t he k eynote o f the f uture w ill b e a nd s hould b e d iversity rather t han s tandardisation and t he g iant i ntegrated i nformation s ystem ( 1975, 3 31). I n o rder t o j ustify the expenditures n ecessary f or the c reation of a data bank, o ne n eeds t o question i f t he p roblems a t h and are s ufficiently p ermanent. I ndeed, automation b ecomes possible a nd d esirable o nly when a particula r function must b e p erformed r epeatedly i n p recisely the s ame manner. This i s not often t he case i n a rchaeology. Great f oresight i s r equired by the d esigners of data banks t o p redict the k inds of questions t hat f uture u sers w ill a sk. I f t he predicted questions never materialise then the data bank b ecomes a white elephant, a n expensive exercise i n a nswering a particular query. Unless kept i n p erspecti ve, the o rganisation of t he d ata bank can become a n end i n i tself,

overwhelming

The

p lea

f or

the

a rchaeologist with

s tandardisation

o ften

data.

appears

to

r epre-

s ent a n a ttempt t o d issuade competitors. Ultimately, the p roblem t ends to r esolve i tself. Standardisation evolves a s o ne system emerges a s t he most w idely u sed. This may not b e a f air s olution but i t s eems p referable to l egislating f or s tandardisation i n a rchaeology. Nature a nd h istory t estify t o the value o f d iversity. A l ittle a narchy i s not a dangerous

t hing.

The s ame conclusions have b een r eached i n other d isciplines, both i n the natural a nd social s ciences. I n biology, S hetler has b een h ighly c ritical o f t he myths which underlie much data-banking a nd c oncludes t hat: a ny s cientist who t ruly b elieves t hat the c omputer i s a l iberator has n ever r eally experienced f irst hand t he bondage t his s tereotyping, c hannelizing machine

can

i mpose

( 1974,

9 7).

The E conomic a nd Social Research C ouncil's approach t o data-banking i s t o accept t apes o f data i n any f ormat along w ith d etails o f the r ecording c onventions. The Data Archive now h olds over 2 500 data s ets c omprising E SRC-funded p rojects, a nd government a nd c ommercial sources. Thus data c an b e made available t o other r esearchers, w ithout i nsiste nce upon s tandardised r ecording f ormats. P erhaps a n a rchaeological body s hould take r esponsibility f or h olding a rchive c opies o f a ll computerised data banks c ontaining archaeological material, whether o f g eneral o r s pecific t ype. I ndeed, the f acilities t o b e o ffered by the RCHM(E) t o accept excavation a rchives i n d igital f orm, whatever t heir s tructure, i s a v ery worthwhile d evelopment i n t his

9 8

a rea. Of course, s tandardisation i s not always a bad t hing. At one l evel, cataloging, i t i s a n admirable goal. H ere the work o f the MDA has b een exemplary. However, o ne f ears t hat now the t echnology i s c apable o f supporting f ar more extens ive data banks, a nd has put them w ithin the r each of all a rchaeologists, t he Utopian i deals o f the 1 960's w ill b e r evived. I ndeed, one f ears that s uch a ims may b e tacitly a ccepted w ithin our national h eritage o rganisations. The s ame i deals s eem to underlie c alls f or " expert" systems which model t he a rchaeologist. They a ssume t hat there i s a n established body o f a rchaeological knowledge which might f orm the basis o f s uch a n expert s ystem. Attempts t o p roduce " expert" s ystems h ave r un i nto t rouble i n other " fuzzy" a reas ( cf L eith 1 984) a nd o ne suspects that s imilar problems would b e encountered i n archaeology ( see Huggett, t his

volume).

RECONCILING STANDARDISATION

AND DIVERSITY

So f ar, I have b een r ather c ritical and have not o ffered any positive solutions. I s hall now outline how a c ompromi se b etween s tandardisation a nd d iversity m ight b e a chieved. The f ollowing example i s a dapted f rom r ecommendations on h ow t echnology s hould b e d eveloped i n a l arge business c orporation ( McKenney a nd McFarlan 1 982, 1 13-5). Figure 1 t races the s tages o f evolution of a n ew t echnology. The four p hases c an b e c haracterised a s ( 1) i nvestment o r p roject i nitiation, ( 2) t echnology l earning a nd adaptation, ( 3) management c ontrol, a nd ( 4) t echnology t ransfer. We can observe each o f these i n the adoption o f c omputers i n a rchaeological o rganisations. The f irst phase i s i nitiated by the decision t o i nvest i n c omputer t echnology. I n a n a rchaeological organisation i t might i nvolve the purchase o f a s ingle micro-computer, o r a n approach t o a mainframe i nstallation. At t his s tage i t i s envisaged t hat the c omputer s hould b e u sed f or o ne o r more c omplementary p rojects, s uch a s f inds r ecording a nd c ataloging. S taff h ave t o b e t rained h ow t o u se the new t echnology,

but

n ew p ersonnel w ill

rarely b e

taken

o n.

The s econd p hase u sually f ollows, unless t here i s a f ailure due t o poor management, s uch a s t he w rong equipment b eing bought, o r major u nexpected t echnical p roblems, o r what McKenney a nd McFarlan c all "poor u ser i nvolvement", t hat i s, the c omputer s its i n a corner o f the o ffice waiti ng f or s omeone t o l earn how t o u se i t! Such a s etback r esults i n Stagnation A . Most o rganisations i n S tagnation A d ecide t o d isinvest b ecause t he c omputer i ncreased work w ith

f ew tangible The

i nvolves

s econd l earning

b enefits. p hase

o f

a dopting

h ow t o

u se

i t

9 9

f or

a

tasks

c omputer b eyond

s ystem

t hose

i n

F igure

1 :

( After M cKenney a nd M cFarlan

1 982,

E xhibit I V)

4-

C

a , E a ) c n c v

C

v u E

C -

a )

9‚ I )

C

v u

C -

I —

the i nitial proposal. For example, the f inds r ecording c omputer m ight b e u sed to do the unit payroll, o r t o word p rocess excavation r eports. I f n ew i mplementations a re d eveloped s tagnates

the o rganisation a t B .

moves

to

Phase

3 ;

otherwise

i t

I t i s the t hird phase which has b een t he main c oncern h ere. I t i nvolves the d evelopment of s tandards a nd c ontrols t o make, i n business t erms, t he applications more c osteffective. However, McKenney and McFarlan note that c ontrol f or e fficiency i s not a ll i mportant a nd r oom s hould b e l eft f or b roader objectives. Otherwise there i s a d anger o f s tagnating a t C , which i s the p roblem currently f acing a rchaeology. I f s tandards and c ontrols are d eveloped that a re s o o nerous that they i nhibit the p rofitable spread o f the u se o f t echnology, then there w ill b e no i ncentive for i nnovation a nd c hange. This applies both t o i ndividual a rchaeological o rganisations a nd to " British A rchaeology L td" a s a whole. A s noted i n The Harvard Business Review: companies may have t o t olerate a c ertain d isorderlin ess during i ntegration i n order to g ain t echnical experience ( McKenney a nd McFarlan 1 982, 1 15). F inally, c omputers l opment

with a s uccesEful entry to P hase 4 the u se o f spreads t o other g roups, typically w ith t he d eve-

o f

n ew applications.

This model o f c omputer t echnology adaptation t eaches the business world that, amongst other things, t oo much s tandardisation i s a dangerous t hing. Management s hould r esist moves towards greater c ontrol f rom systems managers. I f, a s Cooper ( this volume) a rgues, a rchaeology s hould r egard i tself a s a business which must f ollow a n optimising s trategy, then w e s hould l earn f rom t his model. A rchaeolog ists must s eek a compromise b etween t oo l ittle c ontrol a nd t oo much s tandardisation. I n

c onclusion,

we

should

make

the

computer

our

s ervant, not our master. We s hould b e the o nes who d ecide what i s t o b e r ecorded, not the c omputer s ystem. G iven the s tate o f c omputer t echnology, t he question o f s tandardisati on i s l argely a r ed h erring i n r espect o f h ardware, and g iven t he s tate o f a rchaeology, i t i s l argely a r ed h erring i n

r espect

o f

the

data

a s

well.

ACKNOWLEDGEMENTS This

paper

i s

l argely

a s

d elivered

a t

t he

c onference,

a lthough c ertain a lterations have b een made i n t he l ight o f f ormal a nd i nformal d iscussion which t ook p lace b oth t hen a nd l ater ‚ f or which I am g rateful. I would a lso l ike t o t hank my c o-editor, Malcolm C ooper, f or p ointing out value o f t he Harvard Business Review a s a u seful s ource p ractical advice f or a rchaeologists.

1 01

the o f

REFERENCES Chenhall,R. G. 1 968. "The impact of computers on archaeol ogical theory: a n appraisal a nd p rojection", Computers a nd the Humanities, 3 (1), 1 5-24. 1971. "The a rchaeological data bank: a progress Computers and the Humanities, 5 (3), 1 59-69. -

Cleere,H. 9 -20.

1 984.

Doran,J. and archaeology.

"Only

connect",

i n

Martlew,R.

r eport",

( ed.),

1 984,

Hodson,F.R. 1 975. Mathematics and computers Edinburgh University P ress, Edinburgh.

Gaines,S. 1 984. "The impact of computerized systems on American Archaeology: a n overview of the past d ecade", Martlew,R. ( ed.), 1 984, 6 3-76. Graham,I. r ecording 4 7-9.

1 980. "Microcomputers f or a rchaeological a draft s tandard", i n Stewart,J.D. ( ed.),

-

L eith,P. 1 984. "When the expert The Guardian, 2 5/10/84, 1 7.

systems

turn

t o

i n

i n

1 980,

t errorism",

Martlew,R. ( ed.) 1 984. I nformation s ystems i n a rchaeology. New Standard Archaeology, Alan Sutton, Gloucester. McKenney,J.L. and McFarlan,F.W. 1 982. "The i nformation a rchipelago maps a nd bridges", Harvard Business Review, 6 0(5), 1 09-19. -

RCHM(E) 1 975. Report o f the working party o n archaeological r ecords. Royal Commission on H istorical Monuments ( England). Richards,J. D. and Ryan,N.S. 1 985. a rchaeology. Cambridge University

Data processing i n P ress, Cambridge.

Schneider,M.J. 1 971. "Archaeological data the editor, Computers and the Humanities,

banks", l etter 5 (4), 239-41.

Scholtz,S. and Chenhall,R. G. 1 976. "Archaeological banks i n theory a nd p ractice", American Antiquity, 8 9-96. Shetler,S. G. banking",

1 974.

Taxon,

"Demythologizing

2 3(1),

b iological

data 4 1(1),

data

7 1-100.

Stewart,J. D. ( ed.) 1 980. Microcomputers i n a rchaeology. Museum Documentation A ssociation Occasional Paper 4 , Duxford, Cambs. Whallon,R. 1 972. "The c omputer i n a rchaeology: a c ritical survey", Computers and the Humanities, 7 (1), 2 9-45.

1 02

t o

REAL AND

IMAGINARY

Gary

L IMITATIONS OF MICROCOMPUTERS A RCHAEOLOGY L ock

a nd

D ick

I N

Spicer

Hairdressers, p ig farmers, a nd s econd-hand booksellers can buy complete hardware a nd software systems off the s helf which a re d esigned to c ater f or their every need. A ll three g roups of p eople operate p rofitably, i f modestly, w ithin t he normal confines of business; a rchaeologists, on the o ther hand, do not. I t i s h ighly unlikely that a ny commerc ial enterprise will produce a specifically archaeological s ystem, and i f i t d id, p robably only hairdressers, p ig f armers and so on could a fford to buy i t. Unlike these and many other specialist g roups o f u sers, a rchaeologists have absolutely no i nfluence on the mass computer market. That the computer market w ill continue to have i ncreasing i nfluence on archaeologists i s i nevitable, however, s imply b ecause we have to work w ithin the constraints o f the same economic system. The i ncreasing availability of microc omputers i s r eaching epidemic p roportions a nd i nfesting every a spect of a rchaeology. There i s no known a ntidote! One r eason for t he rapid spread o f this epidemic i s d eliberate s elf-exposure within the archaeological f raternity. We choose to use computers not only b ecause o f the ubiquitous i nfluence of the mass market but a s a r esult o f peer-group p ressure: the n eed to maintain t rench c redibility. Computers a nd software a re boom i ndustries, a nd a rchaeologists a re not i mmune to the r esulting commerc ial c laims which can p roduce a misguided p erception o f what computers actually do, a nd o f how much t ime a nd e ffort n eeds to b e i nvested to g et them to do anything meaningful. Without

the

b enefit

o f

customised

s ystems

a rchaeolog-

i sts have acquired a motley s election of hardware a nd must either use widely available commercial software o f t he ' universal' k ind, or write d edicated programs of their own. I n both cases advice w ill p robably b e sought f rom w ithin the established a rchaeological computing f raternity. This p aper w ill argue that a dangerous s ituation has d eveloped b ecause of the p resent l ow l evel of appropriate knowledge o f most computing a rchaeologists. There i s a s erious l ack o f d iscussion c oncerning p roblems and v irtually no c riticism of working s ystems. The majority of publications on the subject, h owever t rivial, a re p resented within a n ethos of achievement. Recent examples o f this complacent a ttitude a re the c ollection of 1 5 papers ( Martlew 1 984) , o f which only one ( Voorrips 1 984) i s i n any way c ritical o f current computer applications i n a rchaeology, a nd the 2 2 p apers p aper o f the

g iven during the 1 984 CAA conference. offers a c onstructive c riticism of the a rt with suggestions f or i mprovement.

1 03

The p resent current s tate

HISTORICAL

PERSPECTIVE

The u se of computers rapidly d eveloped f rom a n a ctivity p ractised o nly on t he f ringes o f the d iscipline to b ecome a fundamental part o f Kuhn's ' normal science' ( Kuhn 1 970). The essence of this i s that a ny n ew t echnique i s adopted i n a s elf-validating a nd u ncritical way: h ence the c omputer i s now s een a s an e ssential part o f the f ashionable a rchaeologist's expanding toolkit, even t hough the archaeologist may not b e quite sure what to do w ith i t. During t he l ate 1 960s and 1 970s there were f undamental c hanges i n the theoretical outlook o f a rchaeologists which i nvolved t he i ntroduction of n ew methodological approaches. The d evelopments have b een v iewed w ithin t he Kuhnian model a s a r evolution, or paradigm-shift r esulting i n the i nitial a ttempts o f a rchaeologists t o b ecome ' scientific' ( Clarke 1 973). I n the current c ontext, h owever, i t i s important to d ifferenti ate b etween two types o f s cience which w e c an d efine according t o archaeologists' expectations. O n the o ne h and i s ' hard' science, t ypified by some p iece o f mystical machinery t o which we p resent data a nd f rom which g et a n a nswer, t he c lassic ' black box' s ituation o f which r adioc arbon dating i s a well k nown example. I n such c ases the a rchaeologist h as no control over t he p rocess b ut, more i mportantly, does not expect any. On the o ther h and i s ' soft' science, r epresented by a r igorous approach t owards data processing and t he t esting o f i nterpretative models; t his i s t otally w ithin the c ontrol o f each p ractising a rchaeologist and has b een t he basis o f a rchaeological thinking s ince t he 1 960s. I n spite o f o ne o r two p ioneering i ndividuals the u se o f computers has n ever b een ' properly' absorbed i nto the mainstream. I t should b e possible t o i dentify a c hanging r elations hip b etween t he machine a nd the u ser s ince t he t ime, t wo d ecades ago, when c omputers were v ery much part o f hard s cience. The f ew that were available t hen were mainframes, worked by experts who p resented a rchaeologists w ith the r esults o f a r equested a nalysis. I t was a p rivilege t o b e allowed to s it a t a t eletype o r t o punch c ards t o i nitiate a s tatistical process, b ut t here was no n eed t o k now what happened within the computer i tself. Knowledge o f h ow the data was s tored o r o f the b ehaviour o f the machinery was u nnecessary b ecause o f t he s eemingly l arge p ower and c apacity o f the machine. This c ondition, which w e m ight c all ' mainframe myopia' , i s s till p revalent t oday. I t might j ust b e t olerable i n mainframe u sers, b ecause t heir machines a re even b igger a nd f aster n ow ( though their d ata s ets a nd p rograms a re c orrespondingly l arger), b ut i t cannot b e j ustified i n p eople working with the l imited r esources of the m icrocomputer. There i s a d istinct l ack o f theory i n a rchaeology t o back up t he r apidly i ncreasing u se o f the computer, and a particular absence o f g uidelines f or microcomputer u sers. The t heoretical r esponse t o t he p roliferating c haotic p ractice o f t he s eventies w as t he ' New Archaeology' which g enerated a whole r ange o f n ew approaches to data. A ' Super-Nova A rchaeology' i s n ow

1 04

n eeded, harnessing t oday's dazzling explosion o f c omputer power b efore a rchaeologists' i nterest f izzles out and l eaves b ehind t he means t o f ind s olutions to s o many questions. I t i s a s ad f act that i n a rchaeology the p ower o f computers i s f ar f rom b eing maximised, a nd i t i s t he poor quality o f s oftware a nd i ts misuse which produces the i maginary l imitations o f m icrocomputer s ystems i n our t itle. Although t hese l imitations a re u ser-generated they a re p erceived a s absolute a nd f inal; t he g enuine l imitati ons a re, i n f act, only t hose o f the hardware. I t i s i mperative that u sers r ecognise these two c eilings a nd a ttempt t o narrow t he d istance b etween them. Archaeologists s hould b e p repared t o a ssimilate a spects o f c omputer s cience i nto their overall ' scientific' outlook, which must i nclude a full u nderstanding o f software engineering. This i s the opposite opinion t o Voorrips ( 1984), who v iews the p rospect o f a rchaeologists writing s oftware w ith ( perhaps j ustified) h orror, advocating the u se of ' off-thes helf ' packages w ithout u nderlying expertise b eing n ecessary o r d esirable. Richards ( 1985) has gone part-way i n p roposing two l evels o f s kill: the c omputer l iterate a nd t he computer expert. Whilst we do not d isagree with t his d istinction we f eel that i t i s s till c entred upon t raditional computing knowledge: both g roups s hould b e more p recisely s killed t o encompass a reas which h ave a particular i mportance t o a rchaeology. There a re f undamental elements o f g ood p ractice which must b e adopted by a ll u sers, a nd the computer l iterate a rchaeologist c annot b e p ermitted t o u se bad t echniques i f p rogression t o c omputer expert i s envisaged. Beginner o r expert, a ll computer-using a rchaeologists s hould b ecome more ' computerate'. This w ill r esult i n a ' softening' o f a ttitudes towards microcomputers which w ill a llow t he u ser much b etter control.

HARDWARE A lthough we a re c oncerned h ere mainly w ith m icrocomputers i t i s i mportant i nitially t o e stablish t heir position w ithin t he w ider f ramework o f hardware options. The c haract eristics of mainframe computers have not a ltered s ignifica ntly over t he l ast f ew y ears: they have a lways h ad r elatively l arge c ore memory, f ast s torage access, a nd the f undamental ability to handle l arge quantities o f data. The o nly i mprovements which take p lace u sually r esult i n g reater speed t o the u ser. A typical 3 2-bit mainframe i nstallation m ight have, s ay, 1 6 megabytes o f core memory, a nd half a dozen hard d isk drives o f a round 2 00 megabytes each. Transfer o f data f rom t hese d rives i n and out o f m emory i s v ery f ast typically 8 00 k ilobytes p er s econd due t o t he u se o f d edicated d isc h andlers. With t his s ort o f r apid data exchange, c ore memory and d isk s torage c an a lmost merge. P owerful methods o f i mplementing ' virtual m emory' c an g ive t he u ser apparently u nlimited available memory space, i n which many l arge f iles may b e c reated, modified, a nd d estroyed during t he c ourse o f p rogram -

-

1 05

execution entirely of the u ser.

automatically

a nd w ithout

t he

awareness

I n comparison, the average m icrocomputer s eems puny, with p erhaps a maximum of a quarter megabyte o f memory, and one o r two d isk drives o f o nly a megabyte each. D isk a ccess i n a micro i s v ery much s lower t han i n a mainframe, a nd v irtual memory t echniques a re not successful. Handling l ong f iles i n a micro ( as anyone who has word-processed more than a half-dozen pages w ill k now) i nvolves t he machine's l aborious l oading of parts of t he f ile i n a nd out o f memory, u sing t emporary storage f iles, i n a n i nelegant a ttempt t o p erform l ike a mainframe. These t echniques a re s lower b ecause o f the ' one-job-at-a timet n ature o f current hardware ( which means t hat a d isk a ccess halts a ny other execution which may b e r equired a p roblem s till n ot f ully overcome despite a ttempts a t ' multi-tasking'), a nd t hey o ften have t o b e employed by t he applications p rogram i tself, rather t han by t he operating s ystem. The overall r esult i s a c lumsy and s low p erformance even during r outine data handling which worsens exponentially a s d atasets i ncrease i n s ize. -

These a re only a f ew of t he f undamental d ifferences b etween t raditional mainframe c omputers a nd modern m icros, y et many computing a rchaeologists s till e ncourage the b elief that the d ifferences a re o nly i n s cale: "The m icrocomputers of today a re comparable w ith t he b ig s ystems o f f ifteen y ears ago." ( Voorrips 1 984,47); " ...today's m icrocomputer i s a s p owerful a s y esterday's mainframe" ( Flude 1 984,34) By wrongly c omparing the philosophies o f approach t o two d ifferent machine types i n t his w ay, u sers a re d evelopi ng d istorted p erceptions o f, a nd g enerating a rtificial r estrictions upon, their s ystems. U sing a m icrocomputer a s i f i t were a mainframe r esults i n r esources b eing exhausted b efore l ong; the imaginary s ystem l imits w ill h ave b een r eached: a c asualty o f such a n approach i s t he a pparent f ailure of the Mucking Excavation Database ( Catton, Jones a nd Moffett 1 981), r eported by Moffett ( 1985). A fter a half d ecade o f microcomputer u se i t i s s till d ifficult t o a ssess t he quality o f applications; i t i s o nly now b ecoming c lear t hat c ertain a rchaeological t asks c an not b e p erformed o n a small machine. But the solutions a re not m erely l imited t o the choice b etween micro a nd mainframe, t hey i nvolve p roper methods o f machine u se: the correct c hoice a nd application o f software. And a s we s hall s ee, s ensible c an effectively r aise t he p erceived l imits l imits o f the hardware.

u se of a machine t owards t he r eal

The g ap b etween m icros a nd mainframes has b een f illed by various types o f m inicomputers t o t he extent t hat d efinition b ecomes hazy. I t i s p robably n ow t rue t hat the p roliferation o f machines p ermits t he c hoice o f a computer suitable f or every application. Those a rchaeologists worki ng

i n

e stablishments

f ortunate

1 06

e nough

t o

have

a

m ini-

c omputer m ight b e quite c ontent w ith the memory s ize a nd p rocessing power of t he machine, a nd t here c an h ardly b e a ny doubt that, w ith u nrestricted a nd u nshared a ccess, t he m ini s ize i s a r ealistic o ne f or most a rchaeological n eeds. But such a major i nvestment w ill occur s o i nfrequently t hat t he c orrect c hoice o f machine i s paramount t o avoid p remature obsolescence a nd i ts c onsequences. Whilst the l atter may also happen with micros ( as t hose w ith eight-inch d isk drives h ave p robably experienced) the i nvested s um i s c onsiderably l ess, a nd a m icro i s r ather more portable a nd adaptable t han a m ini: s o even now we h ear of f our o r f ive y ear old micros b eing r elegated to mundane t asks s uch a s word p rocessing a nd d ata c apture. This s ort o f dynamic u se o f a machine i s to b e e ncouraged r ather t han s uppressed, i n o rder to make b est u se of t he t remendous b oom i n t he c onsumer micro market. C ontrary t o popular b elief t here i s not a l ot o f d ifference b etween t he c omputational power o f the v arious types o f m icro currently available. Manufacturers, n aturally, c annot s uppress their i nstincts t o extol the unique v irtues o f t heir own p roducts. This p romotes the s tiffening o f a ttit udes towards micros t o t he extent that o nly t heir mechanic al capabilities a re a ssessed, a nd their potential a s malleable tools c ontrolled by t he software a re i gnored. When p eople t alk o f t he l imitations o f m icrocomputer s ystems i t i s s ignificant t hat i t i s only i n t erms o f m emory c apacity a nd s torage c apacity that i s, i n t erms o f h ardware. -

One o f the p roblems w ith a n 8 b it m icrocomputer i s the small amount o f memory that i s available. 6 4kbytes i s r eally not s ufficient f or database purposes.... I t may b e possible to upgrade t he d .b.m.s. t o a 1 6 b it m icrocomputer... ( Moffett 1 984,107) Hard d isc s ystems c an c ontain data: 5 megabytes.. . would b e 1 984, 3 5)

a v ery l arge amount o f a small s ystem. ( Flude

What p recisely i s a ' large amount' o f data? F or B enson ( 1984, 5 9) 5 megabytes r epresents 2 0,000 s ites; f or F lude ( 1980, 2 7) about 1 0,000 c ontexts. Machine data s ize s hould not b e c onfused with a rchaeological data s ize; f aced w ith a l arge data s et, most c omputing a rchaeologists would r espond w ith a n i ncrease i n hardware r esources. But r aw data c an b e c ontracted ( or expanded) w ithout l oss o f i nformation, b y p rogram manipulation. We b elieve that a ttention t o s oftware t echniques i s o f g reater i mportance t han t he p resent obsession w ith h ardware, a nd t hat i t c ould h ave much more f undamental and f ar r eaching e ffects o n t he d evelopment o f t he d iscipline. To appreciate t hese, h owever, a rchaeologists must a ttempt t o throw o ff popular misconceptions c oncerning m icrocomputers a nd b egin a s erious a ssessment o f t heir r eal

1 07

capabilities. To a id t his p rocess w e o ffer d iscussion o n just three i mportant a reas: t he possibilities of s tandardi sation, c hoice o f l anguages, a nd data compaction t echn iques.

STANDARDISATION I n 1 980 a working party r eviewed t he s tate o f the market a nd suggested a standard f or m icrocomputers a eology. The r eport s tated that:

c urrent i n a rch-

a s tandard c annot l ive f orever, a nd a n a ttempt a t s tandardisation now must not b e s een a s a n a ttempt t o d elay the i ntroduction of n ew hardware a nd s oftware a s i t b ecomes available. ( Graham 1 980, 4 7). I t s eemed even t hen t hat t he d iversification o f hardware was a threat t o the v ery s tandard b eing p roposed, a nd this was a t a t ime when only two o r three machines c ame onto the market p er y ear. W ith the current much l arger s election o f hardware i t appears pointless t rying t o f ossil ize a dynamic s ituation by i mposing a ny f orm o f h ardware s tandard. We a re not against a co-operative d ecision by i ndividuals a nd/or g roups i n matters o f hardware but t his must d evelop spontaneously f rom mutual i nterests a nd experi ence at g rass roots l evel a nd not b e i mposed f rom above. The d ifficulties encountered i n s tandardisng hardware a re d isturbing b ecause t hey h ighlight a more f undamental p roblem: that o f t he non-portability o f s oftware. T his i s obviously unhealthy f or t he g rowth a nd d evelopment o f c omputer applications i n a rchaeology a s t he d issemination o f software can not o nly p revent duplication of effort but may a lso pass o n p rogramming s kills. To c lear the way f or meaningful software exchange, current c onstraining a ttitudes

n eed

t o

b e

b roken

d own.

Once i t i s a greed t hat a ny s tandardisation adopted s hould b e o n t he s oftware f ront, t hen the f irst a rea where energy should b e expended i s i n a n a ttempt t o overcome the hardware d iversifications o f t he c urrent market. The many and varied p hysical f ormats o f d isks a lmost completely d isa llow a ny f orm o f i mmediate d ata exchange b etween d ifferent models of computer. A r ecent modest survey ( Marland 1 984) o f a f ew CP/M machines l isted 6 2 d ifferent f ormats o f d isk s torage ( out of which one b rand n ame was l isted f ifteen t imes!), a nd t he s ituation i s s imilarly c haotic f or o ther operating s ystems. I n spite o f this, the o nly i nsuperably i ncompatible element h ere i s o f d isk s ize: 8 , 5 .25, a nd n ow 3 .0, 3 .25, and 3 .5 i nches. All other parameters ( density, s ides, skew, s ector s ize, etc) t end t o b e s oftware c ontroll able t o some d egree. I t i s possible i n most c ases f or a p rogrammer t o bypass t he operating s ystem o f a computer a nd to r ead f rom a nd write t o t racks u sing t he ' primitive' subroutines o f the machine. By each of the machines currently

1 08

adopting t hese methods f or i n u se by a rchaeologists,

and by choosing some sort of standard Lowest Common Denominator format, data and software exchange could conceivably take place. This sort of effort might be justified when balanced against the reward of being able to choose from a wider range of hardware. In addition to the area of 'physical' or hardware formats, there is considerable confusion over data formats. We should make it clear that this is completely under the control of the user's program. It is not our intention here to discuss the wider issue of what sort of data should or should not be stored on computer, and whether it, or how much of it, should be prepared ready for some future national database (what we might describe as the interface between archaeologist and archaeologist), except to say that such points have little bearing on the choice, use, or misuse of the actual machines. What is of particular impor­ tance to this discussion is the archaeologist-to-computer interface: the way in which the chosen data is captured, stored, and represented. Many archaeologists do not realise that this area is totally within their control, and that a national standard of data storage and a local idiosyncracy can exist side by side without mutual exclusion. Without actually changing the data, the method by which it is stored may be allowed to vary considerably between comput­ ing units. A national standard of software makes no sense as a standard: how one person does a particular job does not necessarily need to be anybody else's concern, so long as the results meet with the standards of others. All that is necessary is that the software is capable of producing an output file conforming to some agreed format. To this end, we would suggest that guidelines be proposed for the transfer of data in a form (not necessarily the most compact or efficient) most able to be read by every type of program. These might be nothing more than definitions of maximum field lengths, of delimiters, and of physical formats. It would be hasty and presumptious of us to describe such a standard here, for we would expect it to evolve from open discussion, and we would not wish to fall victim of 'resident expert' syndrome, in which the individual to take the first step in using new technology is regarded from that moment on as the unchallenged 'expert' by the rest of the team, whether this status is deserved or not. It can often be a case of the blind leading the blind - with the leader being the person who first found the stick. Difficult and awkward though this syndrome may be within a small group of individuals it becomes a serious matter when it occurs within a national framework. So, for example when one team begins to use a computer for a particular job, other groups, either through choice (through inability, or di$inclination to design for themselves) or by outside pressures or directives, may adopt techniques which would not be acceptable to normal commercial computer users. Most harmful is the situation of the group in a position of authority or power setting itself up to direct others in 109

the u se of computers. The r esult i s a l ack of c ritical f eedback to the ' expert' g roup, a p robable i nflation o f i ts s tatus, and the consequent complacent a ttitude t o p rofessional s tandards. T he a rchaeological f raternity h ave always r esisted s uch i mposition upon t heir own activities, though not a lways w ith s uccess: I c an think o f three occasions i n the p ast y ear when I have b een t old by the p roud possessors o f a n ew mini o r m icro-computer t hat t hey h ave not adopted the CEU s ystem b ut have worked out o ne o f t heir own which i s s uperior i n some e soteric way. This may p ermit them t o i ndulge i n s ome n ew a nd exciting f orm of number-crunching, but i s i t r eally i n t he b est i nterests o f r esearch? ( Cleere 1 984,16) The i mplied support f or a ' resident expert g roup' i s f ostering the l ack o f t he d evelopment o f g ood s oftware by advocating complacency t owards t he p revailing l evel o f c ompetence: one o f the n ew p rograms r eferred t o m ight actually b e considerably b etter than the ' preferred' s ystem. I t i s damaging t o the d iscipline t o s tifle spontaneity, although a t the s ame t ime we n eed t o c ontrol undue duplication o f effort. This i s c urrently a n i nsoluble contradiction which w ill only b e a ttacked by a much more v igorous i nterchange o f i deas, establishing a more c onsistent base l evel of computing awareness.

THE USER-MACHINE

I NTERFACE

We c an a ll b e deceived by the mystique which normally surr ounds a ny n ew t echnology. This c an b e s een t o operate even a t the l owest l evels: i f we b elieve the advertisements f or domestic micros, w e should f ind p rogramming o ne o f t hese machines t o b e v ery , s imple. The whole c onfidence t rick i s exemplified by t he o ld c laim " In 2 4 h ours y ou w ill b e talking t o i t l ike a f riend". I t i s the raison d 'etre o f BASIC that i t s hould appeal t o f irst t ime u sers, a nd i n the i nterests o f sales t hat machines appear f riendly. I t i s easy f or a s oftware engineer t o put a f riendly ' gloss' o n a product. Most BASICs d o l ittle more t han t o f amiliarise the u ser w ith t he hardware; a ny further pursuit a long t he l ines o f t he home micro w ill r esult i n a h igh d egree o f s kill i n what c an n ever b e more t han i nefficient p rogramming. I t i s not j ust t he r esident BASIC which g ives t he i mpression o f ease, but the now w idely available packages, f or example, of database management. W e must make i t c lear t hat a s f ar a s t he domestic o r business u ser i s c oncerned, t hese machines a nd their s oftware a re u sually adequate, s ince r elatively small d atasets a re i nvolved. However, the a rchaeologist has a n eed f or both l arge a nd ( more i mportantly) w ide-ranging data handling. C omputer d istribu tors a re s eldom aware o f t his special r equirement, a nd h ence t hey a re n ot i n a good p osition t o a dvise o n t he choice o f machine o r s oftware. The type o f d atabase p rograms

available

f or

m icros

1 10

t ends

t o

b e

r ather

d ifferent

f rom those o n mainframes. They have the advantage o f b eing s imple t o u se, o ften with a n i nteractive mode which enables t he u ser t o examine f iles a s t hey appear i n t he machine, o r t o monitor the p rogress o f a p rogram. For example, dBase 1 1/111 o ffers t hree l evels o f u se: t he f irst, t he s imple i nteractive mode, i s t he o ne f amiliar t o a ll u sers; the s econd a llows t he execution o f p rograms o n t op o f the above; and the t hird i s a s tripped d own v ersion f or running t ested a nd d ebugged p rograms f aster. However, this type o f package s till has t o t rade o ff efficiency i n f avour of ease o f u se. Each i nstruction has t o b e i nterpreted during execution ( in ' real t ime') a nd the space occupied by the i nterpreter means that l ess space i s available f or data u se. Hence p rograms running w ithin these packages may well operate much more s lowly than specifically w ritten f rees tanding o nes. All t his l eads t o a d ilemma f or a micro p urchaser: whether t o r ely o n modifying a c ommercial package a s the n eed a rises o r to s tart f rom s cratch, l earn a l anguage, a nd actually write c omplete p rograms. E ither way w ill p robably l ead to a n i diosyncratic approach t o the p roblem, a lbeit w ith duplication o f s omeone else's effort, the ' re-inventing the wheel' s yndrome which i s n ow well d ocumented ( Martlew 1 984, 8 ), i n which those d etermined e nough w ill c ontinue with t eeth g ritted a nd eventually p roduce a p rogram working i n o ne way o r a nother, but which may b e i nflexible and i ncompatible with anything else. During t he f ew months t hat t he p rogrammer i s l ocked i n c ombat with the machine, compromises may b e enforced by t ight s chedules, and i solation f rom the r est o f t he a rchaeological t eam w ill p robably occur which may well l ead t o a p runing down o f the o riginal objective. Apart f rom t he f act t hat s uch p rograms often w ill b e badly s tructured, s low, a nd not f ool p roof, o ne m ight wonder whether a n a rchaeologist should not b etter spend . h is t ime doing a rchaeology. ( Voorrips 1 984,48). We c an i magine a world c onsisting o f t eams o f a rchaeologists, each with a computer expert who i s d oing p recisely t he s ame t hing a s t he n ext o ne. Outside this a rchaeological e nclave the c ommercial manufacturers a re busy mass p roducing y et more enticing machines, a ll i ntentionally i ncompatible, a nd a ll promising unlimited power a nd f lexib ility t o the u nsuspecting purchaser. Their easy-to-use l anguages and their p rogrammer-friendly applications p ackages a re specifically d esigned f or non-experts t o u se. I t f ollows that the p rogramming c oncepts which these p ackages o ffer t o t he u ser a re not particularly a dvanced; t he natural human r eaction i s t o a ssume that they r epresent a ll t hat t here i s t o k now about p rogramming. The r eal danger i s not apparent a t the outset, when execution s peed a nd d isk access t imes a re w ell w ithin a cceptable l imits b ecause of the small data s et, but a t a much l ater s tage, w hen the s ystem collapses u nder t he w eight o f a massive f ile, and i t i s o ften t oo l ate t o s tart again.

1 11

The c lumsiness o f i nterpreted l anguages a nd t he s lown ess o f off-the-shelf c ommercial packages can both b e overcome by programs written i n s tructured a nd compiled l anguages, s uch a s P ascal o r t he more modern C . The l atter i s r apidly gaining i n popularity with n ew machines o f a ll s izes, s ince many operating s ystems ( such a s UNIX) a re now written i n C and i t i s a n easy matter f or manufacturers t o ensure a h igh degree o f c ompatibility b etween machines ( though they d o not a lways c hoose t o do s o). With t ruly c ompatible s oftware now i n t he offing, i t makes s ense f or the a rchaeological f raternity to l ook again a t s oftware d issemination, though t his s hould n ot n ecessarily b e i n t he f orm o f f ully i mplemented p rograms, but r ather a s small modules, f unctions o r s ubroutines w hich c ould b e c ombined by the u ser t o p roduced a n efficient tailor-made p ackage. The d isadvantages which c urrently b eset t he u ser o f unfriendly operating s ystems c an b e overcome b y writing customised overlays d esigned specifically f or n on-expert u sers. Although t he UNIX operating system i s f ar f rom p erfect, i t has, a long w ith i ts l ookalikes, t he s upreme advantage of permitting t he manipulation a nd alteration o f i ts own c ommands. W ith a concerted effort o n t he p art o f computer-using a rchaeologists a nd a w illingness t o publish o fferings, a l ibrary o f u seful a nd a bove a ll, e fficient, r outines c ould b e built u p, a nd a s ensible s tandard f or data f ormatting c ould b e evolved, r elying a s i t would o nly o n a half-dozen o r s o f ixed routines out o f the l arge r epertoire which c onstitute t he whole application p rogram. We s ee such a l ibrary c onsisting of a c oordinated s uite o f modules ( written u sing agreed f ormats) which c an b e l inked i n a ny combination according t o the s pecific application. A s cheme has r ecently b een outlined by Ryan ( 1985) u sing s tandard UNIX l ibrary r outines. This could b e extended by d edicated routines s o t hat the w hole c ollection m ight appear t o the u ser a lmost a s a l anguage i n t he way t hat the modules a re manipulated, while a t t he s ame t ime b eing archaeologically specific a nd permitting v arious l evels o f u ser f riendliness. The s uite c ould g row a nd d iversify according t o the r equirements of t he u sers, a lthough the fundamental modules which operate specifically o n t he d ata a nd t he machine ( the p rimitives) must b e written by c ompetent p rogrammers t o e nsure maximum efficiency. I t i s t o t his c rucial n eed f or efficiency i n microcomputer u se t hat w e now turn. DATA STORAGE Even experienced u sers o f machines have t o b e r eminded o f h ow much space i s t aken up by spurious e lements w ithin t heir d ata. D atabase u sers s hould b e f amiliar w ith t he potential r edundancy i n u sing f ixed f ormat f ields, but i t i s not j ust the i nvisible spaces b etween i tems i n a f ormatt ed f ile which c an b e r emoved, though these a lone p robably c onstitute t he b iggest f actor o f s pace wastage. H ere w e must d istinguish b etween s uperfluous spaces ( as d iscussed b elow) and spaces t hat r epresent t he absence o f d ata. W e r eproduce ( figures l a a nd l b) part o f a v ery l arge data

1 12

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f ile u sed o n a mainframe by one o f the authors t o i llust rate this point. Another case of d ata r edundancy m ight b e that too much d etail h as b een s tored. W e could t ake f or example numbers which a re s tored w ith u nnecessary d ecimal places, o r the overkill i n the u se o f coordinates a ccurate to 1 0 metres when d rawing a map of the British I sles o n a n A4 s heet o f paper, j ustified perhaps i n a master f ile f or z ooming i n o n a small part i n which c ase only a f raction o f the f ile would b e u sed but o therwise s erving o nly t o s low down computers a nd p lotters w ith t oo much data. Another case, o ne which a lso d emonstrates t he t rade-offs b etween data s torage efficiency a nd p rogram complexity, i s h idden duplication o f data. A f ile containing numbers o f burials on a s ite m ight h ave f igures f or men, women, a nd c hildren ( and p erhaps unidentifiable). I t would b e wasteful not t o u se the computer's power t o c alculate out the total n umber o f i ndividuals by adding up sub-totals, rather t han i ncluding t his data a nd t hus occupying a nother whole f ield. This concept i s u tilised by Reilly a nd Z ambardino ( 1985) i n their program t o d efine l and boundaries, where i nput data i s checked f or r edundancy a nd a s ystem o f f lags i s u sed t o s ignal which l ines a re s hared b etween which boundaries. -

-

We would a rgue t hat many bad h abits a re r emnants o f a p re-computer era, dating f rom the t ime when a ll data h ad t o b e s tored o n paper. During the early days o f computerised data capture these p re-computer p ro-forma sheets were s imply t ranscribed i n their entirety, spaces a nd a ll, i nto card image sheets f or machine entry. With h indsight o ne c an s ee the f utility o f t rying to design data f orms c ompatible with optimum c omputer s torage which a re a lso easy t o r ead a nd f ill i n. The f orm r eproduced i n f igure 2 , i f u sed t oday, would b e a n extreme example o f a n i nefficient i nput data s heet. Though n ever actually i mplemented, i t i s evidently d esigned t o b e easily f illed i n by a n a rchaeolog ist, w ith w ell d efined a reas s eparated by l arge s paces. Whilst this example was d eveloped w ith the c onstraints of a f ixed-length r ecord machine ( Wilcock 1 974), what s hould b e considered i n the d esign of this f orm i s t hat t he blank a reas r epresent space i n c omputer m emory even w hen n ot f illed with data. The entire eighty-column w idth i s r ead f or every horizontal row ( each r ow b ecoming o ne punched c ard), so t he number o f bytes o f memory which t his f orm r epresents i s a total o f 8 0*14=1120, o f which o nly 5 60 a re u sed f or data! I n addition t o t his wastage ( which w e hasten t o point out i s extreme) t here i s more i n t he r epetition o f the 6 5 bytes o f t he s ite n ame, county n ame a nd s o o n a t the t op o f the f orm: The f irst three c ards o f each r ecord g ive s tandard i nformation t hat may b e p rinted o n t o t he s heet, s ince i t r emains c onstant f or each p it r ecord. ( Shackley 1 976,12) Not o nly i s t his to b e punched by stored

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justification for this type of data to be stored more than once in a computer. It is this sort of superfluous repet­ ition in data files which is the commonest cause of data overflow in any machine. The number of cards used for recording the pits excavated in the 1973 season exceeded 8000, and will rapidly become unmanageable as the excavation prog­ resses. It is therefore planned to store all the data permanently on magnetic tape (ibid,15). This is an advanced case of mainframe myopia where the power of the machine is viewed as being unlimited and capable of dealing with any archaeological situation with­ out the need to take heed of system requirements or limita­ tions. Indeed, an almost perverse pride can sometimes be sensed in the sheer volume of data: Our current record length comprises 67 fields with a nominal limit of 30,000 characters per field. The system is entirely word-based and each field is essentially unformatted (Loy 1982,116). Mainframes are still abused in this way but the effects are not glaringly obvious; the danger is so much greater when such users switch to microcomputers. Non-computerate people continue to see the data in the machine as an image of the card they filled out. The naive user is encouraged to believe that each item of data is held physically separate from its neighbours in the machine; that this is so radically removed from the truth is shown in figure 3. This misapprehension is perpetrated by the use of analogies such as 'little boxes' and 'railway trucks' in the popular literature for computer beginners. It is another verson of mainframe syndrome, which can strike down the micro-computer user particularly if there is the possibility in the future of an upgrade to the system, whether in the form of a hard disk add-on or even of a new machine altogether. The problem is that once poor programming practice begins, the wrong response will be triggered when data overload occurs. Instead of looking at the rectifiable faults in the software, the user will look at the hardware limitations, request the upgrade, and con­ tinue to fill the computer with more and more inefficiently stored data. The result is that when the upgrade overflows, so much time and energy will have been expended that it is too late for restorative action. Inevitably, our approach is a compromise with regard to available finance, but in an 'either/or' situa­ tion, we prefer to enhance our data collection capa­ city rather than our existing processing capacity. (Benson 1984,57) Probably claustrophobia

the - a

worst syndrome is a sort of data a fear of compacting data inside 116

Fi gure

3

X2 '- '- '- '- 'BREAL AND IMI TATI ONS OF MI CROCOMPUT ERS IN ARCHAE0L0GY«81 -M -J Gary Lock and D i ck Spi cer •JHaj rdre] ? 4

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machine. I t i s a ccompanied by the worry that s omehow control might b e l ost over t hat data i f i s i s s tored i n a f orm other than pure t ext. This i s c learly a w idespread d isease, s ince we a re told "Archaeology d eals w ith a l arge amount o f data mostly i n the f orm o f t ext" ( Flude 1 984,34). Those p eople who h ave carried out computer r esearch o n a rchaeological data would r efute t his! Computers a re, o f course, well suited t o d eal with t ext, a s t he t remendous boom i n word-processors has s hown. A rchaeological data i s not pure t ext, a lthough i t i s normally presented a s such; most elements can b e r educed t o a numerical f orm o f s ome k ind, a nd the sort o f a nswers a rchaeologists w ill expect f rom a computer must a t s ome s tage i nvolve numerical analysis. I t makes s ense that this a nalysis b e p erformed o n numbers a nd not t ext! This may s eem a t ruism when w e think of s tatistical work, but i f we l ook a t the s ort o f s imple r ecovery which i s p erformed a ll t he t ime o n-site, off-site, and i n unit offices, f or example "which c ontexts c ontain s heep-bones a nd haematite-coated bowls?" o r " how many stone c ircles i n Wales have c airns c lose by?" they normally i nvolve a number o f s imple Boolean t ests to b e p erformed o n the data. What b etter than f or the c omputer to r educe the question t o a s imple Boolean f ormula and t o t est i t o n purely numerical data? A p roper r elational database ought t o b e able t o p erform i n this way a s a matter o f c ourse, but most packages f or microcomputers c annot d o t his easily. I n i ts s implest f orm data c ompression n eed b e nothing more than the s ubstitution o f a p iece o f data ( a k eyword) by a number, which takes up l ess room i n the machine. I t i s plain that i f the word i s a l ong one, a nd i s u sed f requentl y, then a considerable s aving i s made, s ince the o riginal word i s only s tored once f or r eference. This c an b e applied t o a ll sorts o f r epetitive data, a nd a ny o f the k eywords c ited i n the many publications c oncerned w ith ' standardisi ng the r ecord' c an b e a fforded this t reatment. Thus our question about the s tone c ircles c an b e r educed t o a f ew numbers, o ne r epresenting ' Wales', others ' Stone C ircle' a nd ' Cairn', a nd a nother f or ' Grid r eference'. -

-

The

b enefits

of

this

t echnique

a re

many

a nd

cumulative: 1 ) I nformation c an b e compacted to b e a f raction of s ize i t was i n t extual f orm t his means that more data b e accommodated o n a d isk w ith advantages o f economy -

l ess media

the can a nd

handling.

2 ) P rogram execution i s f aster b ecause f ewer d isk a ccesses a re n eeded t o t ransfer t he same amount o f data ( since operating s ystems r ead a nd write t o the d isk i n f ixed blocks). 3 ) The analysis o f both t he s earch numerical 4 )

The

t he k ey

data w ill also take l ess a nd the data exist i n

t ime, s ince a s maller

f orm. s ystem

has

a n

automatic e rror

1 18

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f acility

built i n, l ookup.

s ince

t ext

entry w ill

a lways

i nvolve

a thesaurus

So why has this not b een more w idely u tilised? P erhaps i t i s b ecause s uch t echniques a re not particularly well documented i n the ' user-friendly' p ress, a nd t he uninitia ted r emain unaware of them. F rom those who a re, the main a rgument a gainst t hese t echniques s eems t o b e based o n t he f ear that data i n a n encrypted f orm c annot b e examined, c hecked o r edited easily. A ny p rogram, h owever, that compacts data must therefore b e capable of r estoring i t to i ts o riginal f orm, a nd outputting the r esults i n a f ormat chosen by the u ser to a ny d evice, p rinter o r d isk. I n a ny c ase, a s we have s een, the p rocess o f s toring data o n d isk i nvolves a method of encoding, a nd we must r emember that t ext editors a re t hemselves programs which d ecode a nd r ecode data i nto f ormats f or d isk s torage. I n c onclusion we will r eiterate t he p roblems a nd s ugg est d irections i n which p rogress may b est b e made. The a rchaeological computing s ituation s eems to b e unique; the data s ets i nvolved a re u sually v ery l arge a nd variable w ith t he desired a nalyses r anging f rom s imple l istings o r catalogues to complex s tatistics. The hardware a nd s oftware available t o cater f or these d emands a re o ften pathetically i nadequate. Hardware i s s everely r estricted b y l imited budgets a nd s uitably specialised s oftware i s not commercially available, f orcing a rchaeologists t o t ry t o g et by w ith g eneral packages o r t o w rite t heir own. Reinforcing these n egative a spects i s the overall l ack o f appropriate knowledge o f most a rchaeologists. This i s well i llustrated by t he commonly h eld b elief t hat one machine and one p rogram s hould b e capable o f doing most things a ny a rchaeologist n eeds. I n particular a rchaeologists must not b e c omplacent. We s ee v ery l ittle evidence f or " a g radual maturing of knowledge about h ow t o u se computers i n a rchaeological work" ( Gaines 1 984,71). The main t heme o f our r ecommendations i s that archaeologists must b e p repared t o work a t c omputing a nd i ncrease t heir k nowledge o f computing science c oncepts. Because of the l ack o f support by the c omputer i ndustry and the specialised n eeds o f t he a rchaeological computing f raternity w e a re f orced i nto the p osition o f mutual s elf-help. This c ooperation n eeds to b e much more coordinated than a t p resent, s o t hat g enuine i nformation exchange i s encouraged. A ny s uch coordination must come f rom t he u sers themselves, where t he r elevant p roblems a re experienced, a nd not b e externally c reated. A s a rchaeologists u sing computers we f eel t hat the a dvancement o f p rogramming s tandards i s b eing hampered by t he u se o f BASIC rather t han a s tructured l anguage. Of t hose p resently available C s eems to o ffer t he b est l ong t erm p rospects a s well a s b eing a v ery p owerful l anguage, o fferi ng a s i t does the b enefits o f a h igh l evel s tructured l anguage and the a ttributes o f a machine-language a ssembler. a

modest

C c ompilers f inancial

a re

available

i nvestment

1 19

f or

although

most machines

t he

f or

r equired mental

i nvestment i s somewhat h igher. has b een adopted the exchange

Once a structured of software b ecomes

l anguage s impler.

The publishing o f l istings of modules, subroutines a nd algorithms should b e encouraged; such practices are commonp lace i n other d isciplines: s tatistical j ournals, f or example, often contain programs. This would h elp prevent the considerable duplication o f effort that i s p revalent today. Our r ecommendations a re o ffered o nly a s examples o f immediate solutions t o overcome the present imaginary l imitations o f microcomputers. A ny a ttempt a t s tandardising hardware s eems t o b e futile other than i n the a reas such a s t ransfer baud r ates a nd f ormats f or d isk f ile t ransfer. Standardisation of software controlled elements i s much more f easible. The Lowest Common Denominator f ormat f or data would b e a good s tart; i t only needs agreement o n f ield parameters a nd delimiters. The u se o f data compaction t echniques i s only one example of the fundamental good practice which must develop w ith the i ncrease i n t he u nders tanding o f computing concepts. W ith the hardware and software odds s tacked so h eavily against u s i t i s i mperative that we perceive the r eal rather than the imaginary l imitations o f our systems. Archaeologists must accept that commercial h elp will never b e of much use, and that p rogress c an o nly come f rom combined efforts w ithin the profession. "Don't l et u s make s o many r eal ones Natured Man.)

imaginary evils, when y ou know we have t o encounter" ( Goldsmith, The Good-

REFERENCES Benson,D. 1 984. " Information t echnology: application by the Dyfed Archaeological Trust", i n Martlew,R. ( ed.), 1 984, 5 4-62. Catton,J. P.J., Jones,M.U. and Moffett,J.C. 1 981. 1 965-1978 Mucking excavation computer database", Applications i n Archaeology, London, 3 6-43. Clarke,D.L. 1 973. "Archaeology: Antiquity, 6 7, 6 -18.

the

Cleere,H. 1 984. 1 984, 9 -20.

i n

Davidson,D. A. earth science Flude,K. a eology" -

1 984.

" Only

and and

connect",

l oss

o f

" Setting i n

up

a n

archaeological

Martlew,R.

( ed.),

1 20

( ed.),

G eoarchaeology:

1 980. " Computing i n the Department i n Stewart, J . ( ed.), 1 980, 2 5-30.

i ntroduction"

i nnocence",

Martlew,R.

Shackley, M.L. 1 976. the past, London.

"The Computer

o f

computer

1 984,

3 1-44.

Urban

system

A rch-

-

a n

Gaines,S. ( ed.) 1 981. Archaeology. Arizona.

Data

Bank

Applications

i n

1 984. "The i mpact of computerized s ystems o n American Archaeology: a n overview of the past decade". i n Martlew, R . ( ed.), 1 984, 6 3-76. -

Graham,I. r ecording 4 7-50.

1 980. "Microcomputers f or archaeological a d raft s tandard", i n S tewart,J. ( ed.),

-

1 980,

Kuhn,T.S. 1 970. The Structure o f Scientific Revolutions. ( 2nd edition), U niversity of Chicago P ress, Chicago. Loy,T.H. 1 982. " Experience with the National I nventory P rogramme o f Canada", Computer Applications i n Archaeology, Birmingham, 1 14-6. Marland,A.

1 984.

" Shedding

a bit

Formats", CPMSDOSUGUK ( Journal Group UK), 2 (4), 4 9-59.

o f

o f

L ight

the

on

Disk

CP/M a nd MSDOS

Users'

Martlew,R. ( ed.) 1 984. I nformation systems i n a rchaeology. New Standard Archaeology, Alan Sutton, Gloucester. Moffett,J. C. 1 984. " The Bedfordshire County S ites and Monuments Record Database Management System", Computer Applications i n Archaeology, Birmingham, 1 01-9. 1 985. "Archaeology, databases and microcomputers". P aper g iven a t t he 1 985 Computer Applications i n Archaeology c onference, London. P roceedings to b e published. -

Reilly,P.

a nd

Zambardino,R.

1985.

" Boundary

a nd the Manipulation of Ancient Boundaries: Approach" i n Voorrips,A. ( ed.), 1 985. Richards,J.D. computers". 2 , 2 -5.

1 985.

"Training

Archaeological

archaeologists

Computing

Associations a Computerised

to

u se

Newsletter,

Stafford.

Ryan, N.S. 1 985. " Some thoughts o n a n a rchaeologist' s t oolkit", paper g iven a t t he 1 985 Computer Applications Archaeology c onference, London. P roceedings t o b e published.

i n

Shackley, M.L. 1 976. "The Danebury project: a n experiment i n s ite s ediment r ecording" i n Davidson a nd S hackley ( eds.) 1 976, 9 -20. Shackley,M.L.

a nd Wilcock,

J . D.

1 974.

Danebury and the Computer". Computer Archaeology, Birmingham 8 2-90.

"Pit-sediments Applications

a t

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Stewart,J.D. ( ed.) 1 980. Microcomputers i n Archaeology. Museums Documentation Association Occasional Paper No. 4 , Duxford.

1 21

Wilcock,J. D. 1 974. "The f acilities Science and Archaeology, 1 1,16-24. -

i n

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t he

P LUTARCH s ystem"

1 981. " Information Retrieval Applications f or Archaeology Britain" i n Gaines,S.W. ( ed.), 1 981, 1 00-122.

Voorrips,A. 1 984. " Data catchment c arrying capacity", i n Martlew,R. 1985. ( ed.) To Pattern the Methods i n Archaeology, volume -

1 22

analysis a nd ( ed.), 1 984,

computer 4 5-53.

Past: Mathematical 1 1. P . A.C.T., Amsterdam.

EXPERT SYSTEMS

I N ARCHAEOLOGY

Jeremy Huggett

I NTRODUCTION The a im o f t his p aper i s to examine s elected a spects o f a rtificial i ntelligence and t o d escribe some o f the p roblems a nd t he potential t hat the u se o f s uch t echniques may offer a rchaeologists. Discussion w ill b e r estricted p rimarily t o the s ubject o f ' problem-solving', s ince t his f acility i s b ecoming i ncreasingly available i n the f orm o f c ommercial expert s ystem shells a nd i s t herefore o f more i mmediate i nterest t han those a reas which a re s till s trictly experimental. A number o f a rchaeological expert s ystems have r ecently appeared, but there has b een l ittle d iscussion c oncerning t heir application i n t he d iscipline. A s tandard d ictionary d efinition o f i ntelligence i s " an ability t o r eason a nd understand" ( Fink 1 968, 2 09), but t o s uggest that machines can b e c apable o f s uch a thing t ends t o r aise a s torm o f p rotest a nd philosophical d iscussion s ince there i s a n i nherent implication i n this t hat p eople a re t hemselves no more t han machines. H owever, a rtificial i ntelligence may b e d efined a s " the science o f making machines do things which would r equire i ntelligence i f done by man" ( Minsky 1 968, v ). M insky's d efinition o f machine i ntelligence r equires o nly t hat t he machine s hould s imulate i ntelligent a ction, not b e i ntelligent i tself. This b ehavioural d efinition s eems more appropriate s ince, when the p rogram o f a n ' intelligent' machine i s examined, i t i s c lear t hat the i ntelligence i s only apparent, a chieved by means o f c lever p rogramming d evices. McCarthy a nd Hayes ( 1969, 4 66) s ee i ntelligence a s consisting o f two p arts: the epistemological part, a r epres entation o f i nformation o r knowledge; a nd the h euristic p art, a mechanism t hat s olves p roblems w ithin t he r epresented domain o n the basis o f t hat knowledge. ( 1977, 1 7) d efines a rtificial i ntelligence a s:

Boden

the u se o f p rograms a s t ools i n the s tudy o f i ntelligent p rocesses, t ools t hat h elp i n t he d iscovery o f the t hinking p rocedures a nd epistemological s tructures employed by i ntelligent c reatures. Thus a rtificial i ntelligence r equires b oth a k nowledge ( or r epresentation) o f a particular s ubject o r d omain a nd the ability t o r eason w ithin that model world. D ecision-making w ithin t his domain i s s een a s b eing f undamental t o i ntellig ence a nd c rucial t o p roblem-solving a ctivities ( Millar 1 971). The r equires

s imulation that

o f

computers

t hese

" intelligent

s hould

b e

1 23

able

t o

p rocesses" l earn

f rom

experience, t o organise i nformation i n s uch a way t hat i t c an b e manipulated i n s olving p roblems, a nd p resumably t o p erform a t something approaching a h uman l evel o f ability ( see F ink 1 968, 2 09,225). I n o ther w ords, a machine d isplaying a rtificial i ntelligence should b e c apable o f s olving p roblems by d eploying r elevant knowledge f rom i ts knowledge base, or i f the k nowledge i s not there i t s hould b e a ble t o r ecognise t his a nd ' learn' by adding t o i ts knowledge base. Whether t his constitutes ' intelligence' r emains open t o question. A dedicated machine w ith domainspecific knowledge may appear t o b e i ntelligent within i ts own s phere, but outside i t, i t i s c omparable t o a n ' idiot s avant', " capable o f p erforming mental m iracles within a s ingle narrow category y et otherwise o f s ubnormal i ntelligence" ( Michie 1 982, 1 35). Any d iscussion o f machine i ntelligence i s c learly f raught with d ifficulty a nd p erhaps the s afest a ttitude i s t hat: . .

.

. .

.

i f the special t ask which a p rogram p erforms i s a v ery d ifficult o ne by human s tandards w e may c all the p rogram ' powerful', but we s till d o not call i t i ntelligent ( Michie 1 982, 1 35). . .

.

.

I t may therefore b e u seful i f emotive t erms s uch a s ' clever', ' intelligent', o r ' understanding' which may c reep i nto d iscussion o f s uch machines a nd t heir programs are qualified by the u se o f i nverted c ommas o r " scare-quotes" ( Boden 1 977, 1 7). C lassic examples o f early machine p roblem-solvers a re those p rograms applied t o problems i n chess ( see M ichie 1 982) and d raughts ( see Samuel 1 963), f or i nstance. These employed ' heuristic programming' t echniques i n o rder t o a ssist w ith s olving t he p roblem, r ather t han u se a ' brute f orce' method. The ' brute f orce' approach g ives " a b igger bang f or t he buck" ( Michie 1 982, 1 80) i n that i t i s s impler ( and t herefore cheaper) t han the h euristic approach; h owever, i n a ttempting t o solve t he p roblem i t w ill evaluate a ll the possibilities open t o i t. S uch a n approach i s c learly i mpractical: i n c hess, f or example, t here a re estimated t o b e 10**120 possible board positions, a nd 1 0**40 i n d raughts ( Boden 1 977, 5 12). Theoretically, s uch a s earch a lgorithm w ill eventually p roduce t he a nswer, although i t may t ake a considerable t ime t o do s o. W ithout t he u se o f h euristic programming t echniques, a s ystem would pursue approaches l ong a fter a human p roblem-solver would have r ealised t hat a solution was n ot i n s ight. This b rute f orce t echnique i s otherwise known a s the ' British Museum Algorithm' ( Newell, Shaw a nd S imon 1 957; Raphael 1 976, 5 9), so c alled b ecause i t s eems a s s ensible a s p roviding monkeys w ith t ypewriters i n o rder t o r eproduce a ll the books i n t he British Museum. A human p roblem-solver d oes n ot a ttempt t o c arry out a n exhaustive s earch o f a ll available options but l imits evaluation o f t he p roblem by i ntuition, experience o r ' common-sense' t o t he a rea where a s olution s eems most

1 24

l ikely. Such human h euristics t end to i ntuitive g uesses, o r, a s Boden s ays:

b e

' rules-of-thumb',

human r easoning even o f the most ' explicit' o r ' rigorous' t ype, a s i n s cience a nd mathematics employs i ntegrative principles o f tacit i nference o r g lobal k nowledge o f which o ne i s n ot i ntrospectively aware, but which u sually d etermine the nature o f the t hought c ontents o f which o ne i s f ocally aware ( 1977, 4 35; quoting M . P olanyi). -

-

Heuristic p rogramming a ttempts t o emulate t his k ind o f b ehaviour by g reatly r educing the a rea s earched, but a s a c onsequence r isking the c hance o f overlooking t he s olution altogether o r f inding o ne that i s l ess t han s atisfactory. Putting these t hought-processes i nto words i s a notoriously d ifficult task s ince, a s S loman ( 1971, 2 72) s ays: Many p ersons can r ecognise a nd u se v alid i nferences even though they have l earnt no l ogic a nd b ecome i ncoherent when a sked t o explain why o ne t hing f ollows f rom a nother... The i nability o f a human expert t o express c learly, i f a t all, this k ind o f tacit i nference poses a major p roblem i n a ttempting t o u nderstand t he m eans by which a h uman problem-solver a rrives a t a solution. I n t erms o f device i s s imply:

a rtificial

i ntelligence,

a

h euristic

a m ethod t hat d irects thinking a long t he paths most l ikely t o l ead t o the goal, l ess p romising avenues b eing l eft u nexplored ( Boden 1 977, 3 47) a nd which "offers solutions t hat are g ood e nough most of t he t ime" ( Feigenbaum a nd F eldman 1 963, 6 ). Two main types o f h euristic may b e i solated g eneral h euristics, c ommon t o most t ypes o f p roblem, a nd special-purpose h euristics, r estricted t o a s pecific problem a rea ( Feigenbaum a nd F eldman 1 963, 6 ). The f ormer t end t o d efine t he t ype o f s earch s trategy, while t he l atter define the a ctual r oute t hat the s earch t akes, u sually by calculating a c rude w eighting f or each decision i n a n a ttempt t o s imulate t he human ability t o a ssess approaches a nd s ituations. S earch s trategies a nd h euristic w eighting w ill b e d iscussed i n more d etail b elow. -

EXPERT

SYSTEMS

A c riticism o f work i n a rtificial i ntelligence during the l ate 1 960's a nd early 1 970' s ( for example, Sammet 1 971) was t hat i t was o n t he whole applied t o r elatively t rivial p roblems, particularly g ames s uch a s c hess a nd d raughts, f or i nstance, a lbeit w ith some s uccess. A s a r esult, the 1 970's d evoted

s aw t o

t he

d evelopment

solving

o f

a number

p ractical

1 25

problems

o f i n

c omputer t he

r eal

s ystems world.

Such systems a ttempted t o formalise t he knowledge o f human specialists ( or domain-experts) i n o rder t o model t heir r easoning and thus b e able t o r each conclusions t hat would c orrespond with t hose o f the human experts g iven s imilar c ircumstances. Examples of such ' expert s ystems' i nclude DENDRAL, a s ystem which analyses t he s tructure o f organic compounds and c an outperform human experts i n the f ield ( see, among others, Buchanan a nd F eigenbaum 1 978); P UFF, which i nterprets lung function t ests ( for example, s ee Hayes-Roth, Waterman a nd L enat 1 983, 3 2-5); MACSYMA, which performs symbolic d ifferential and i ntegral calculus ( for example, Barr a nd F eigenbaum 1 982 vol.2:143-49); I NTERNIST, which carries out i nternal medical d iagnoses ( see Barr and Feigenbaum 1 982 vol 2 :197-202); MYCIN, which i dentifies bacteria i n b lood and u rine and r ecommends t herapy ( Shortl iffe 1 976); PROSPECTOR, d esigned t o a id mineral exploration ( Duda et a l 1979); and a n umber o f others ( see, f or examples a nd r eferences, Barr a nd F eigenbaum 1 982 vol.2; Michie 1 982 f ig. 14.4; Weiss and Kulikowski 1 984 table

1 .1;

Winston

1 984).

Expert systems that have b een specifically applied to a rchaeological problems i nclude a s ystem f or ageing domestic animals f rom their t eeth ( Brough and P arfitt 1 984); a c lassification system for Beaker p ottery ( Bishop and Thomas 1 984); a s imulation p rogram for t eaching purposes o n the excavation of a burial mound ( Dean a nd Nichol 1 984); and a c lassification s ystem f or wine amphorae ( Bourrelly

a nd

Chouraqui

1 984).

Before d iscussing the application o f expert a rchaeological p roblems, a b rief examination characteristics and operation will b e attempted. An

expert

system

i s

a ' problem-solver'

systems to o f their

program

which

has knowledge of a narrowly-defined area built i nto i t, t ogether with a n i nternal model o f a domain-expert's r easoning and problem-solving know-how, a nd u ses these f eatures t o s imulate t he performance of the human specialist i n solving problems i n the same f ield. The system i s presented w ith a p roblem or s ituation by t he u ser, a nd i s not only able t o r equest further i nformation i f r equired, but i t can also explain i ts steps i n r easoning. Thus t he system may b e i nterrogated about questions t hat i t has a sked the u ser, o r about the s tage i t has r eached i n i ts i nvestigation, o r about the conclusions i t has offered. I n addition, the expert s ystem should a lso have a c orrective f acility s o that n ew knowledge may b e added o r f aulty knowledge altered by the human expert. Expert systems a re s een a s ' models o f competence' ( Hartley 1 981); they a re not i ntended t o act a s models o f human r easoning ( as a number o f earlier ' problemsolvers' were), but a re primarily p erformance-orientated, d esigned t o p roduce c ompetent r esults i n the d omain o f expertise. a re

They: not

r esulting

c oncerned with systems

and

1 26

s imilarities human

b etween

p erformance

t he

( except

i nsofar a s t he l atter may p rovide a possible h int about ways to s tructure t he domain o r to a pproach the problem, o r a s a yardstick f or s uccess...) ( Davis a nd K ing 1 977, 3 06). Ultimately, a n expert s ystem i s s een a s a cting a s a c onsultant o r a dvisor. Weiss a nd Kulikowski s ee expert s ystems a s s erving a s " interactive i ntelligent p roblems olving a nd advisory s ystems that augment the c apabilities o f t he u ser" ( 1984, 1 0). M ichie ( 1982, 1 97) d ivides t his c onsultancy function o f expert s ystems i n three ways, which h e d efines i n t erms o f "user-modes". The expert s ystem may b e approached w ith t he u ser i n the r ole o f a c lient o r pupil, obtaining i nformation a nd l earning about the special ism o f t he expert s ystem through a s eries o f questions a nd a nswers. Alternatively r oles may b e r eversed and t he u ser a cts a s tutor: r efining, modifying o r e nlarging t he s ystem's k nowledge. An expert s ystem may b e s een a s having t hree main parts f irst, t he knowledge base which c ontains t he r ules a nd f acts about t he domain; s econdly, a c ontrol s ystem o r i nference engine which applies the r ules; a nd t hirdly, a g lobal data base c onsisting o f a s tore o f i nformation concerning the consultation a t hand ( Weiss a nd Kulikowski 1 984, 4 1). A k nowledge-based s ystem i s f undamentally d ifferent f rom a conventional p rogram i n t hat the k nowledge i s made explicit i n the f orm o f f acts a nd r ules, rather t han b eing implicit i n the coding o f the p rocedures and modules f ound i n a s tandard s ystem ( Sowa 1 984, 2 78). The s ystem i s r ule-driven, i n that problems a re s olved by the a pplication o f r ules f rom t he k nowledge base, a lthough t he a ctual r epresentation o f these r ules may v ary. -

KNOWLEDGE REPRESENTATION The most common f orm o f knowledge r epresentation, and a rguably the most successful i n t erms o f r esults t o date, i s the ' production system' ( see, among others, Davis and K ing 1 977; W eiss a nd Kulikowski 1 984). A p roduction system knowledge base c onsists o f a s eries of p roduction r ules a nd f acts s uch a s a re f ound i n MYCIN a nd DENDRAL a nd a re a lso t he basis o f a v ariety o f commercially available expert s ystem ' shells' ( empty expert s ystems t o which a k nowledge base may b e added by the u ser). A production r ule i s basically o f t he t ype " If [ A], t hen [ B]", a lso k nown a s a ' situation-action pair'. An example o f s uch a p roduction r ule t aken f rom a n a rchaeological expert s ystem f or a geing a nimal

t eeth

i s:

< tooth-n> evidence-for i f < tooth-n> i dentified-as < type-of-tooth> a nd < type-of-tooth> present-from < age-range> ( Brough and Parfitt 1 984, 5 3) I n

this

c ase,

t he

knowledge

base

1 27

c ontains

a l ist

o f

t ypes

o f t eeth which a re a ssociated w ith a particular a ge and t his r ule l inks t he f acts known about these age w ith t he i dentity o f tooth-n. An a lternative example Doran 1 977, 4 37) i s: RULE

A :

RULE B :

i f then

[ two g raves i ntersect] [ they a re l ikely t o b e t ime]

i f a nd t hen

[ two graves a re adjacent] [ they do not i ntersect] [ they a re l ikely t o b e s imilar

r ange, ranges ( after

well-separated

i n

i n

d ate]

Note that both halves of t he ' if' s tatement i n r ule B must b e t rue i f the conclusion i s t o b e r eached. A nother r ule m ight u se a n ' or' construct, i n which c ase a t l east o ne of the parts o f the ' if' s tatement must b e t rue. I t s hould b e pointed out h ere t hat t he ' rules' i n a n expert system are not necessarily r elated t o archaeological ' laws' a s characterised by, f or example, Stickel a nd C hartkoff ( 1973), Schiffer ( 1976) a nd Salmon ( 1982). A n a rchaeol ogical expert system might w ell employ r ules t hat c ould b e c lassified a s ' laws' o r ' law-like statements', but a n expert s ystem ' rule' may equally w ell b e s een a s a ' ruleo f-thumb' o r a h euristic device. S uch r ules may appear t o b e t rivial, but t his t riviality i s l argely d erived f rom these often tacit i nferences b eing made explicit. Both ' rules' a nd ' facts' a re f ound i n t he knowledge base, t he d istinction b etween the two b eing t hat f acts a re merely s imple c ases o f rules, having no a ntecedents a nd t herefore nothing t o prove. P roduction r ules a re f undamental t o most expert systems i n one shape o r a nother. Their f ormat i s r igid but even s o they can c arry d ifferent nuances o f meaning. Rules A and B above work from observations to a hypothesis, but r ules c an a lso work f rom hypothesis t o hypothesis f or -

example: RULE

C :

i f

[ the two g raves a re l ikely t o b e s imilar i n date] ( from r ule B ) [ any g rave goods i n t he g raves a re l ikely

t hen

to

b e

contemporary]

H ere, a n i nference c an b e made b etween t wo hypotheses, where the a ntecedent o f r ule C may b e matched w ith the c onsequent o f rule B . I n addition, r ules c an b e u sed t o s tructure o r d irect the r easoning p rocess: i f the system h as b een t old by t he operator t hat t he o ccupant o f t he g rave i n question was male, t hen t here i s l ittle p oint i n t he s ystem a sking questions which w ere d esigned t o d etermine t he s ex o f t he burial. A n ability t o t rap pointless questioning w ill a lso enhance t he apparent i ntelligence The

most

o

the

s ystem

i mportant

i n

the

f eature

1 28

o f

eyes

o f

t he

a k nowledge

u ser. base

i s

t hat

i t s hould b e well-structured, that i s, rules s hould not b e s cattered a t random throughout i t. This s implifies the task o f a ltering the k nowledge base a t s ome f uture d ate, particularly i f t he knowledge b ase i s l arge. A problem that c an a rise i s that a number o f d ifferent r ules may b e f ound t hat have matching a ntecedents o r consequents, a nd some d ecision has t o b e made by the s ystem a s t o which a re l ess r elevant, o r l ess s uitable. Whether a r ule i s appropriate o r not i s d ependent o n t he g iven s ituation. S ome means o f r esolving the c onflict a nd s electing the ' best' r ule i s t herefore n eeded. One way of a chieving t his i s t o g roup t he r ules i nto ' procedures', i n which a ll t he r ules work t owards a s ingle goal ( Davis a nd K ing 1 977, 3 15; L enat e t.al. 1 983). These p rocedures a re s elected a nd t riggered by ' meta-rules' which d irect t he s ystem's r easoning t o the r elevant p rocedures f or a g iven s ituation. This c learly i nvolves a l arger rule base not o nly a re t here a dditional r ules i n the f orm o f the s trategic ' meta-rules' ‚ but some duplication Of r ules b etween p rocedures may a lso b e n ecessary. -

A d evelopment o f t his k ind o f t echnique i s the f orm o f knowledge r epresentation known a s ' frames', ( otherwise k nown a s s cripts o r p rototypes) ( see M insky 1 975; Winston 1 984; Barr a nd F eigenbaum 1 982). F rames r epresent k nowledge about specific s ituations, a nd p rovide a s tructure o r f ramework consisting o f a n umber o f ' slots' which carry i nformation. The a dvantage o f f rames over p rocedures i s t hat they group t he k nowledge more explicitly i nto r elevant c ontexts. Both f rames a nd ' meta-rules' act a s a n i ndex t o t he knowledge b ase a nd f ocus the r easoning p rocess. D ifferences b etween t he two types o f r epresentation s hould p erhaps b e s een more i n t erms o f O rganisation t han any s uggestion that o ne o r t he o ther i s n ecessarily b etter o r more effective. Given the p roven s uccess o f p roduction s ystems i n p roblem-solving, t hese w ill consequently b e t he type considered i n the r emainder o f t his paper. What i s c lear f rom a b rief examination o f k nowledge r epresentation i n expert systems i s that t hey a re quite r igid i n f ormat a nd n eed t o b e w ell-structured. This may raise d ifficulties when such s ystems a re applied t o a n a rchaeological p roblem d omain. The effect o f f ormulating ' rules' a nd ' facts i n a r elatively u nstructured d omain s uch a s a rchaeology i s t o make t he s ubject appear t o b e more objective o r ' scientific', whereas i n f act the p rocess may s imply r einforce t he s ubjective n ature o f t he i nferences and concepts employed.

REASONING

I N

EXPERT SYSTEMS

I n a production s ystem, r ules a re evaluated by a s eries of pattern-matching operations ( see, f or example, M ichie 1 982,199-201) which a re controlled by the i nference engine. This i nference e ngine controls t he r easoning o f t he s ystem a nd

applies

the

r ules

f ound

i n

1 29

the

k nowledge

base

by

l ogic-

a lly matching the premise of a n argument with a r ule. The i nference e ngine does not c hange when n ew knowledge i s a dded t o the system s ince i t i s h eld s eparately f rom the k nowledge base. I n the example g iven above, p resented w ith the premise ' Two graves, X a nd Y , i ntersect', the s ystem might f ind a match w ith the t he a ntecedent o f r ule A which would t rigger i ts consequent, ' The two graves, X a nd Y , are l ikely t o b e well s eparated i n t ime.' A l anguage such a s P ROLOG has t his a ssociative or pattern-matching f acility built i nto i t, while expert system ' shells' generally consist o f a n i nference engine s tripped f rom a well-tried expert s ystem t o which a ny knowledge base can b e added. F or example, EMYCIN ( ' Essential' or ' Empty' MYCIN) i s a n expert s ystem shell consisting of the i nference engine t hat has b een r emoved f rom MYCIN a nd has subsequently b een u sed a s t he basis o f other s ystems, s uch a s P UFF. As w ell a s controlling t he l ogical pattern-matching p rocess, the i nference engine also handles the overall s earch s trategy. The type of s earch c onducted by the i nference engine i s characterised a s either b eing ' forward c haining' o r ' backward c haining', t hough t he two t ypes may b e combined i n a s ingle system. A f orward c haining s earch s trategy w ill s tart f rom known f acts and work t owards a conclusion b y matching a p remise w ith the a ntecedents o f a r ule a nd t riggering o ff the consequents o f that rule ( a p rocess which was d escribed above u sing rule A a s a n example). The p roblem w ith s uch a system i s t hat i t i s d ifficult t o c ontrol; r ules u sed i n t his way a re known a s d emons, a nd may b e f ired o ff by t he addition of a s ingle p iece o f i nformation t o the k nowledge base. The SOLCEM-D s ystem p roposed by Doran ( 1977) f or c emetery a nalysis employed ' recognition demons', f or example. Backward c haining works f rom t he consequents o f rules t o t heir a ntecedents. The s ystem s earches f or a r ule w ith a consequent which matches the p remise a nd a ttempts t o prove t he a ntecedent by t reating i t a s a n ew premise. U sing the example s hown above f rom Brough a nd P arfitt's system for ageing a nimal t eeth ( 1984, 5 3), i f the c onsequent ' evidence-for ' i s matched by t he premise, the s ystem then takes t his c onsequent a s i ts n ew p remise a nd a ttempts t o p rove the a ntecedents '

i dentifieda s a nd < type-of-tooth> p resent-from ' The l anguage P ROLOG, a nd t he expert s ystem s hell APES ( an augmented P ROLOG w ith a query f acility) both operate u sing a b ackward c haining mechanism. I n other words, a f orward c haining i nference engine works f rom known f acts t owards a s olution, while a backward c haining i nference engine works f rom a c onclusion back t o t he f acts i t effectively ' guesses' a t a l ikely s olution a nd -

.

-

a ttempts t o prove i t, moving o n t o a nother s olution i f the p roof f ails. Both types of s earch may b e f ound i n a s ingle

1 30

expert s ystem: MYCIN has a backward c haining i nference engine y et employs a ntecedent r ules which work b y f orward c haining, t riggering d emons i n o rder t o avoid a sking t he u ser pointless questions. S earch s trategy may a lso b e c ontrolled i n a more i mmediate way: b y applying h euristic weightings t o r ules i n o rder t o guide t he s ystem's r easoning by a ssociating w eight ings with potential s olutions. Such h euristic w eightings may not o nly guide the r easoning o f t he expert s ystem but can also i ndicate t o t he u ser the l evel o f confidence t hat c an b e p laced i n t he s ystem's c onclusions. I n s ome c ases, f or example t he expert system Rl ( Sowa 1 984, 2 84), the handling o f such weightings has b een l argely r eplaced by exact l ogical r easoning, but i t s eems h ighly i mprobable t hat a n a rchaeological expert s ystem could operate successf ully without s ome means o f handling uncertainty. Archaeology i s v ery much a n i ntuitive d iscipline a nd i s not a s f ormalised a s t he scientific a nd engineering d isciplines t o which expert s ystems have u sually b een applied. A s a r esult, the ability o f a n expert system t o handle u ncertainty i s particularly r elevant when c onsidering a n a rchaeological p roblem domain. A g eneralisation i n a rchaeology, such a s ' adjacent g raves i n a c emetery a re l ikely t o b e s imilar i n date', i s s imply a r ule-of-thumb: i t may b e patently i ncorrect i n s ome c ircumstances, a nd not a ll archaeologists would a gree that s uch a s tatement was valid. This k ind o f i mplicit h euristic i n a r ule may work adequately i n a well-structured a rea, but f or most applications, a nd particularly a rchaeological p roblems, a more f lexible means o f handling uncertainty i s r equired o f a n expert s ystem. A rchaeologists have t o d eal w ith l arge amounts o f i nexact data, a nd no knowledge base c ould ever b e c onsidered t o b e exhaustive or c omplete.

HANDLING UNCERTAINTY To date, expert systems have h andled uncertainty t hrough a v ariety o f quasi-probabilistic methods u sing c alculated h euristic weights. These a re variously known a s p robabili ties, d egrees o f b elief o r confidence f actors ( see W eiss a nd Kulikowski 1 984 f or examples). The most c ommon r epresentation o f confidence f actors i s t o a ssociate a n umber b etween 1 ( or 0 ) a nd + 1 to a particular s tatement, where 1 ( or 0 ) i ndicates no confidence i n the s tatement, o r l owest p robability, a nd + 1 equals h ighest p robability, o r c ertainty. Confidence f actors a ssociated with r ules a nd f acts t hat a re employed during a c onsultation a re c ombined u sing a n umber o f t echniques, s uch a s v ariations o n the t heme o f Bayes' Theorem ( Shortliffe's Model o f I nexact Reasoning f or i nstance) o r i ntroducing elements o f f uzzy l ogic ( see S tefik et a l. 1 982 f or examples), i n o rder t o g ive a n overall i ndication o f the d egree o f confidence t hat may b e p ermitted i n t he c onclusions. Thus, f or example, r ule B might appear a s f ollows:

1 31

i f a nd then

[ two graves a re a djacent] [ they do not i ntersect] [ they are l ikely t o b e s imilar i n date ( with a c onfidence f actor of 0 .7)]

I n t his c ase the confidence f actor was a ssigned a rbitrarily a nd t his i s a major w eakness o f t he expert system's ability t o handle u ncertainty. H owever r eliable t he manipulation of the confidence f actors may b e, t heir i nitial v alues, a nd any v alues s ubsequently a ssigned t o i nformation p rovided by the u ser d uring t he c ourse o f a consultation, are provided by a n i ndividual. Worse s till, t hey may b e p rovided by s everal i ndividuals, s eparated i n t ime and p lace. The values g iven a nd their consistency w ill d epend ultimately upon t he t he c onfidence t hat t he u ser f eels a t t hat t ime. I nitial v alues f or expressing d egrees o f c ertainty i n a hypothesis a re o nly approximations: t he l evel o f b elief that can b e d isplayed i n the confidence f actors t herefore may not b e c ertain, c ompounding t he problem t hat they were i n f act i ntended t o alleviate. I n addition, o nce a confidence f actor h as b een s ubjectively assigned, there r emains the d ifficulty of t he p robability t hat i s i mplicitly a ssigned t o t he opposite c ondition i n rule B , the unstated implication i s t hat there i s a 3 0% c hance t hat these g raves a re n ot s imilar i n date. -

Many s tudies h ave s hown that experts do not easily carry probabilities i n mind, a nd even when t hey do r eport them, t he numbers do not t urn out t o b e t rue probabilities, b ecause t he r eporting s pecialist w ill o ften deny agreement w ith t he h idden i mplicit probability o f the opposite c onclusion ( Weiss and Kulikowski 1 984, 2 8). . .

A warning a nd H ayes:

about

such

.

p robabilities

was

v oiced

b y

McCarthy

The i nformation n ecessary t o a ssign numerical p robabilities i s not o rdinarily available. Therefore, a f ormalism that r equired numerical probabilities would b e epistemologically i nadequate ( 1969, 4 90). I nadequate o r not, the f act r emains t hat not only a re t hese ad h oc p robabilities u sed, t hey a re u sed w ith s ome s uccess i n s ystems l ike MYCIN, DENDRAL a nd P ROSPECTOR. H owever, g iven the problems a ssociated with t he p rior a ssignment o f c onfidence f actors i n a n expert s ystem, i t may s eem t o s ome t hat t he handling o f s uch probabilities i s s omething o f a j uggling a ct w ith numbers. F or example, C endrowska a nd Bramer

c riticise

MYCIN o n

t he

grounds

that:

t here a re i nterdependence r estrictions that n eed t o b e applied t o t he estimation o f c ertain p arameters ( measure o f b elief a nd measure o f d isbelief i n a hypothesis, supplied by the p hysician) which a re n ot i ncluded i n t he MYCIN model. I n a ddition, t he . .

u se

o f

c ertainty

f actors

1 32

a s

a

means

.

o f

ranking

hypotheses i s also suspect s ince examples c an b e g iven o f c ases where, o f two hypotheses, t he o ne with the l ower probability would have the h igher c ertainty f actor I t i s i nteresting t hat such a f lawed method s hould g ive r esults t hat a re apparantl y a cceptable i n p ractice ( 1984, 4 89). . .

.

.

I f the p rior p robabilities a re h owever s ound t he s tatistical r esulting p robabilities cannot b e A n

a lternative

means

o f

open t o question, p rocedures may b e, t rusted.

expressing u ncertainty

then t he

i s

t o

u se ' fuzzy l ogic' ( see Z adeh 1 979). Using f uzzy l ogic, i mprecise t erms s uch a s ' few', ' several' o r ' many' may b e u sed, each t erm h aving b een p reviously d efined a s having a s et o f values. F or example, ' several' i s l ikely t o imply more than two, but l ess t han t en, therefore a l ow p robabili ty would b e a ssigned to t he ranges 1-2 a nd > 10 with a h igh p robability f or t he r ange 3 -9. Quite c learly, however, the s ame c riticisms made of t he p rior a ssignment of c onfidence f actors may a lso b e l evelled a t these f uzzy l ogic s ets. I ndeed, while t hey may p rovide g reater f lexibility, they also t end t o conceal the a ssumptions t hat were made i n t heir f ormulation more effectively.

EXPERT

SYSTEMS

AND

ARCHAEOLOGY

Having d iscussed t he g eneral c haracteristics o f expert s ystems and touched o n some o f t he problems that a rchaeologists may encounter i n knowledge r epresentation a nd i n d ealing with u ncertainty, one question r emains t o b e c onsidered: why ( or whether) a rchaeologists s hould b e i nterested i n t hese s ystems. This i s particularly r elevant s ince a number o f the most f requently c ited expert s ystems a re not w idely employed i n t heir p roblem d omain. Of those m entioned earlier, I NTERNIST, MYCIN a nd P ROSPECTOR a re not " extensively u sed" ( Weiss a nd Kulikowski 1 984 table 1 .1) i n spite o f having a good t rack r ecord i n t erms o f r eliable r esults. I ndeed, of a ll the medical expert systems only P UFF i s i n routine u se, the r eason apparently b eing t hat: they have y et t o s atisfy the i ndispensability c riterion: They a re not i ndispensible t o t he p ract ice o f medicine, a nd physicians p erform a dequately w ithout t hem ( Barr a nd F eigenbaum 1 982, 1 83). Thus i t n eed adopt t hese they may ethical

b e

not b e s een a s imperative that archaeologists s ystems wholesale, i ndeed i n many s ituations t otally

i nappropriate,

either

f or

p ractical

o r

r easons.

One o f t he major r easons put f orward f or the adoption o f expert s ystems i s t hat they c an b e u sed a s a m eans o f c ommunicating expertise b etween specialists i n d ifferent s ubject a reas. A s B ishop a nd Thomas ( 1984, 5 6) p oint o ut, specialisation i n archaeology i s n ow the r ule. This i s

1 33

c learly the raison d ' etre o f the s ystem f or ageing domestic animals ( Brough a nd P arfitt 1 984), a f ield where i ncorrect i nterpretations may r esult f rom t he l ack o f i mmediately available expertise ( op.cit., 4 9). A s imilar argument i s u sed by E nnals a nd Brough ( 1982) who s ee expert systems a s a k ind o f r eference work t hat may b e consulted by t he nonspecialist. Weiss a nd Kulikowski b elieve that this d issemi nation o f expertise i s a major motivation f or building expert s ystems, a nd c laim t hat t hey c an s ave both t ime a nd money and may b e more accurate and c ertainly more efficient than human experts, who: a re i n short supply, and when available, have l ittle t ime a t t heir d isposal. While t hey may b e v ery proficient a t their work, the possibility o f d istraction by many d ifferent c onflicting d emands makes them more vulnerable t o errors t han a computer -based s ystem ( Weiss a nd Kulikowski 1 984,9). Associated with this i s the b elief t hat expert systems may b e u seful not o nly i n modelling the expertise o f o ne specialist ( for example, Clarke's c lassification o f Beaker pottery s ee Bishop and Thomas 1 984) but t hat o f s everal, thereby e nabling c omparisons t o b e made b etween t he variety o f approaches u sed by experts within a particular speciali sm. One o f the t rends i n expert s ystems outside a rchaeology i s t o a ttempt t o synthesise the experience of a number o f experts i n o rder t o enhance the expertise o ffered by the -

system. This f ormalisation o f knowledge i s c laimed t o b e o ne of the most important r easons f or constructing a n expert s ystem, a nd i t i s considered t hat s uch s ystematisation i s b eneficial t o the host . d iscipline. Weiss and Kulikowski, f or example,

a rgue

t hat:

i n f ormalising the knowledge o f how a n expert human s olves d ifficult p roblems w ith today's b est knowl edge, we are l aying out explicitly h ow future a lternatives may b e sought. A s l ong a s the expert s tates h is r easoning only i nformally and i mprecisel y, i t i s i mpossible t o p in down the alternatives; but a s s oon a s there a re f ormalised s tatements t hat enable a computer t o r eproduce t he outcome o f h uman r easoning, we c an p roceed t o experiment a nd s ee u nder what c ircumstances t hese s tatements a re applic able

( Weiss

a nd Kulikowski

1 984,

1 0).

A number o f major a ssumptions a re made i n this s tatement which r aise questions about the u se o f expert s ystems i n a rchaeology, l argely a ssociated w ith t he p roblem o f t he f ormalisation o f k nowledge that i s i mplicit i n a n expert s ystem. The problem o f f ormalising a rchaeological k nowledge i s not emphasised by the p roponents o f a rchaeological expert s ystems t o date, but i t i s t here n evertheless. There r emains considerable d isagreement w ithin the p rofession a s t o

whether

f ormalisation

a cross

134

the

board

i s

d esirable

o r

even possible. Those a rchaeologists who do not s ubscribe t o the ' scientific' approach to a rchaeology, a s typified by a ttempts to d iscover u niversal g er ieralisations, w ill consequently object t o the formalisation n ecessary f or a n expert s ystem. Conversely, those who b elieve t hat t he s cientific approach i s v alid will presumably b e more w illi ng t o s ee expert s ystems a s having a r ole t o p lay i n t he systematisation

o f

a rchaeological

knowledge.

However, t he d egree o f f ormalisation n ecessary t o construct an expert s ystem i s a f orm o f r eductionism, i n t hat the t ranslation o f knowledge f rom t he i mplicit t o the explicit will i nevitably i nvolve the l oss of elements i n the p rocess. The f ormal, fundamentally d eductive r easoning o f an expert system may b e i napplicable when d ealing with s ome types o f a rchaeological p roblem a nd t he r eduction r esulting f rom f ormalising a body o f k nowledge c an have p rofound

c onsequences:

Science can proceed only by s implifying r eality. The f irst s tep i n i ts p rocess o f s implification i s abstraction. And abstraction means l eaving out o f account a ll t hose empirical data which do not f it the particular conceptual f ramework within which science a t t he moment happens t o b e working ( Weizenbaum

1 976,

1 27).

Even s tating the m eans by which a s olution was not a straightforward p rocess s ince:

a rrived

a t

i s

when we explain t o s omeone how w e s olved a p roblem, we often i nvoke 2 0-20 h indsight a nd l eave out the m istakes t hat w e made a long t he way. Our explanation makes i t appear that we f ollowed a v ery d irect and r easonable r oute f rom b eginning t o end ( Stefik et a l.

1 982,

1 62).

As i f the p roblem o f abstracting a rchaeological k nowl edge i s not s evere enough, expert s ystems potentially p resent t he additional hazard o f f ossilising t he "particula r conceptual f ramework" that was current a t the t ime o f abstraction. I n a rchaeology, h owever, t o u se Hurst's words, "the hypotheses o f y esterday b ecome the b eliefs o f t oday a nd the u ntruths o f tomorrow" ( 1964, 1 49). A rchaeological knowledge i s i n a s tate o f c onstant f lux: s ystematising t hat knowledge c ould have s erious i mplications f or i ts future d evelopment. I t may b e that this over-states the p roblem, but even t hough expert s ystems c an ' learn', t here i s a danger that o nce a n expert s ystem has b een c onstructed, i ts a rea o f expertise might b e s een a s ' complete'. This fossilisation o f k nowledge i n a n expert system i s not h elped by t he ultimate i nability o f the s ystem t o j ustify a ll i ts r ules a nd a ssumptions ( see Clancy 1 983) The s ystem's r esponse t o a u ser's r equest f or i nformation o r a s

' reasons why' i s t o quote r ules f rom i ts j ustification f or making a particular

1 35

k nowledge base a ssumption o r

i nference. However, a s the explanation moves up f rom t he particular t p the g eneral t he r ules t hat can b e i nvoked a s a n explanation b egin t o r un out, u ntil a t l ast t he machine has t o r espond with something a long t he l ines of "because I was t old i t was t he c ase". Some, but not a ll, r ules w ill b e j ustified by f acts h eld i n the k nowledge base, but a ssumpti ons normally h ave to b e made i n d ealing w ith a n a rchaeol ogical problem, and s uch a ssumptions may not b e made explicit i n a n expert system. Even i f they a re s tated, the explanation may b e i nadequate a nd t he s ystem u nable t o p rovide further i nformation. This would p erhaps b e acceptable i f t he s ystem was b eing operated by a n expert i n t he s ame f ield, but could c ause considerable p roblems i f the s ystem was b eing u sed by a pupil o r non-specialist when i ncorrect o r i napplicable advice may b e the r esult. I n o ther words, t he s ystem does not have ' complete' k nowledge about the conceptual f ramework within which i t was constructed. While t he knowledge base c ould b e extended, p erhaps by the i nclusion o f b ibliographical r eferences f or example, t he u ltimate i nability of the expert s ystem t o j ustify i tself w ill always b e p resent. This p roblem also exists i n d ealing w ith t he confidence f actors a ssociated w ith h ypotheses these weights may b e a ssigned by d ifferent p eople a t d ifferent t imes for d ifferent r easons, but the e xpert s ystem, other t han checking t hem f or i nternal consistency, w ill b e unable t o explain why c ertain l evels o f c onfidence were a ssigned t o particular hypotheses. -

THE SUITABILITY OF ARCHAEOLOGY AS A HOST DISCIPLINE D iscussion o f t he motivations b ehind building expert s ystems, a nd their a ssociated p roblems, r aises a f urther question to what extent i s a rchaeology a s uitable medium f or t he application o f these expert s ystems? P erhaps n ot surprisingly, t hose who h ave worked o n archaeological expert s ystems c laim t hat t his i s not i n doubt. D oran, f or example, considers t hat " archaeology has c lear a ttractions a s a p roblem domain f or a rtificial i ntelligence r esearch" ( 1977, 4 33), though h e adds t hat a rchaeological problems have t heir own special characteristics a nd n eed special t reatment. Most expert s ystem specialists appear t o b elieve t hat t here i s no a rea t o which expert s ystems c annot b e eventually applied. P robably t he most u seful approach t o t his question i s to examine t he p articular c haracteristics o f a problem domain that specialists i n expert s ystems l ook f or, a nd t o s ee how f ar a rchaeology c onforms t o t hese -

r equirements. A rtificial i ntelligence experts a re g enerally a greed on the r equirements o f a s uitable p roblem domain. For example, Stefik et a l. ( 1982, 1 42) i solate t hree f undamenta l c haracteristics o f a problem domain: the data a nd k now l edge s hould b e r eliable . ; t hey s hould b e s tatic; a nd t he number o f solutions should b e small. I t i s possible t o r elax these r equirements f or example, u nreliable data c an -

b e

handled

t o

some

extent

u sing

1 36

c onfidence

f actors

o r

f uzzy

l ogic and i ndeed t here are f ew, i f any, p roblem a reas t hat c an b e said t o meet t hese r equirements i n f ull. However, i t may b e a rgued that t he n earer a n application i s t o t hese t hree i deal r equirements t he more r eliable t hat expert system will be. S owa d efines three common f eatures o f application a reas: -

f irst, there exist r ecognised experts i n these f ields; s econd, the knowledge that t he experts have i s quantifiable; third, the knowledge can b e express ed i n d eclarative r ules i nstead o f p rocedures. I f a problem i s s o d ifficult t hat no human b eing knows where t o b egin, no c omputer s ystem w ill b e able t o s olve i t either. I f the p roblem r equires i ntuitive j udgements a bout novel s ituations then t he i ntuition cannot b e f ormalised i n a n expert system. The b est applications f or a n expert s ystem a re o nes that r equire a l arge amount o f well-defined, f ormali sable knowledge ( Sowa 1 984, 2 85). . .

Barr and F eigenbaum conclude expert s ystems that:

f rom a n

.

.

examination

o f

medical

The domain must b e narrow and r elatively s elfc ontained, the c omputer s hould p rovide s ubstantive a ssistance t o the physician, a nd t he task should b e o ne t hat the physician e ither c annot d o or i s w illi ng t o l et a computer d o. ( Barr a nd F eigenbaum 1 982, 1 83). I t i s therefore apparent t hat a rchaeology i s v ery much on the f ringe a s f ar a s t he application of expert s ystems i s c oncerned. Archaeology may have i ts experts, but i t i s d oubtful whether t heir k nowledge i s quantifiable, a nd even i f i t were, archaeological knowledge i s not complete, r elia ble o r s tatic. This must c ast s ome doubt u pon t he utility o f

expert

s ystems

f or

archaeology

i n

g eneral.

Expert s ystems that have b een s uccessfully applied h ave, o n the whole, b een u sed i n areas where the p roblem a nd t he t heory a ssociated w ith i t i s well-structured. That i s, they have b een applied t o p roblems which a re c apable o f b eing effectively r educed t o a l ogical s ystem o f r elations hips. This point may b e made concerning t he a rchaeologic al expert s ystem u sed t o age d omestic a nimals ( Brough a nd P arfitt 1 984). However, most a rchaeological t heory and k nowledge i s a s y et i nsufficiently w ell-structured o r d efined t o sustain expert s ystems i n their current f orm. Weizenbaum f or example, c ompares t he i nterpretation o f the s tructure of molecules f rom mass spectrometer output ( which DENDRAL was s uccessfully d esigned t o c arry out) t o a n

a rchaeological

s ituation;

a p roblem which:

i s s omewhat a nalagous t o that o f r econstructing the l ife o f a p rehistoric v illage f rom the r emains r ecovered by a rchaeologists. There i s, h owever, a n important d ifference b etween the two p roblems: t here

1 37

exists a theory o f mass spectrometry t he analy st i s i n a b etter position t han the a rchaeolog ist, who has no s trong methods f or v erifying h is h ypotheses ( 1976, 2 29-30). . .

.

.

I t i s probably this f eature which makes archaeology a ttract ive to p roponents o f a rtificial i ntelligence a nd expert systems i n particular. A rchaeology p resents them w ith a c hallenge, but t he r esults of that c hallenge may b e o f l ittle u se t o a rchaeologists ( Hunt 1 975, 4 42). Those i n f avour o f expert systems suggest that t hey w ill a ssist progress t owards f ormalisation, but this will b e s een a s b eneficial o nly by those a rchaeologists who w ish t o t ravel along t hat r oad. Archaeology does not s eem to b e the n atura l candidate f or t he application o f expert s ystems t hat some would appear t o b elieve ( for example, E nnals and Brough 1 982; B ishop a nd Thomas 1 984). However, i t may b e s uggested t hat t here are some a reas w ithin a rchaeology which a re c apable o f s ustaining t he systematisation r equired f or a n expert system, and i n which s uch a s ystem m ight actually b e o f s ome u se. The p rerequisi te o f s uch a n a rea will b e t hat t here already exists a body of f ormal a nd s ystematic knowledge which may b e encapsulated i n a n expert s ystem. T o paraphrase Barr a nd F eigenbaum ( 1982, 1 83): t he d omain must b e narrow a nd r elatively s elf-contained, the computer should p rovide substantive a ssistance t o the a rchaeologist, a nd t he task should b e one that the archaeologist either c annot d o o r i s w illing t o l et a computer d o. C ertain specialist a reas, s uch a s s tratigraphical analysis, may b e c onsidered t o b e s uitable c andidates. H ere, f or example, i s a s ubject which has well-defined a nd g enerally accepted ' rules', but which i s a complex a nd r epetitive task f or a h uman. Stratigraphic al s equences can already b e organised by a v ariety o f c omputer p rograms a nd a rguably the a ddition of a d egree o f "expertise' t o these would greatly enhance their p erforma nce. The example s et by DENDRAL could suggest that t hose h ighly scientific areas o f archaeology, s uch a s r adioc arbon dating a nd thermoluminescence, m ight b e s uitable a reas f or the application o f expert systems. Other a reas may d evelop w ith t ime, but i t would s eem r easonable t o r equire t hat such areas achieve a degree o f s tability b efore a n expert s ystem i s applied, r ather t han during t he p rocess o f i ts application. I n other words, w e s hould not b e i n the s ituation o f having expert systems l ooking f or a n application; the subject s hould d ictate t he system a nd not the r everse. Expert systems that a re i ntended f or g eneral u se s hould o nly b e applied t o well-defined a nd ' static' p roblem a reas i n a rchaeology; t hey a re p robably not s uitable f or u se i n f ields t hat a re h ighly t heoretical a nd subject t o the v agaries o f new, o ften mutually exclusive, hypotheses. Current expert l ogical

work

i s

examining

the

possibility o f

s ystems t o the more t raditional f orm database i n order t o a ssist with t he

1 38

applying

of a rchaeomanipulation

of data i n a much more l imited way. S ince a rchaeological data s ets a re fundamentally i ncomplete a nd i nexact, a n expert system could b e of some u se i n partially overcoming s ome o f these p roblems f or the purpose o f a particular analysis. I n the analysis of a c emetery, for example, a lthough the s ex o f many o f the bodies may b e u nknown, i n some cases i t may b e possible to i nfer the l ikely sex f rom, s ay, the g rave goods and a n expert s ystem could b e u sed to i ndicate l ikely male and f emale burials using a v ariety of t echniques. This k ind o f ' intelligent database' s ystem would have to b e u sed with extreme c aution s ince i t may justifiably b e c laimed that i t would b e ' creating' data a nd thereby contaminating the database proper. However, this could b e o ffset t o some extent by the ability t o ' switch off' the expert s ystem a nd i n addition, the data that i t ' creates' during t he consultation or a nalysis need not b e s aved i n the database a t the end of the s ession. Caution must s till b e exercised, h owever, s ince these systems can only b e a s good a s a s the i nformation they contain. While this i nformation may be added to, the s ystem c annot o f i tself improve a bad hypothesis o r concept ( Weizenbaum 1 976, 3 5). I t i s suggested, therefore, that while there may be a reas i n which a rchaeological expert s ystems may b e u sefull y applied, they should for the present b e s een a s r esearch t ools rather than b e i mmediately p laced on g eneral r elease i n the f ield. The widespread and uncritical adoption of expert systems could r esult i n the s tifling o f a rchaeologic al theory, s ince the encapsulation of archaeological knowl edge may i n fact l ead t o i ts s tagnation. D iscussion a nd d evelopment of new i deas may b e s een a s a s ign of a h ealthy d iscipline: the g racing o f a t ool w ith t he t itle o f ' expert' could f orestall this k ind of activity. L each emphasises t he role o f human i ntuition i n a rchaeology: Computers a nd s imilar gadgetry have their proper p lace i n a rchaeological method, but do not f orget that i n the past r eal progress i n your subject has always o riginated i n a n i nspired guess ( 1973, 7 71).

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the

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Duda,R., Gaschnig,J. and Hart,P. 1 979. ' Model Design i n the P rospector Consultant System f or Mineral Exploration' i n Michie,D. ( ed.), 1 979, 1 53-67. Elcock,E.W. and Michie,D. i gence 8 . John Wiley.

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