146
Wehavealsoseenhowaverysimpleevent-notificationinterfacecansimplifythejobof
applicationinterfacingtoPalimpsesteditingservices.Thissimpleinterfacingtechniquealso
offerssignificantpracticaladvantagesbyallowingthereuseofexistinguser-interfacecom-
ponents.

Chapter8 : Summary
Thisdissertationhaspresentedanewanalysisofsynchronizationproblemsincollabora-
tivework,focusingontheuseofexplicitchangerepresentationstoincreasetheflexibility
ofcollaborativeapplications.Theanalysisincludesanewtypologyoftypesofchangeopera-
tions,includinganewdistinctionbetweenstaticanddynamicchangeoperations.Ithaspre-
sentedandformalizedanewmodelofsequenceeditingthatincludesdynamicversionsof
themoveandcopyoperations.Wehaveexaminedapplicationofthemodel,algorithmsto
implementitandapplicationarchitecturestoexploititsadvantages.
TherestofthischapterbrieflyreviewstherequirementsfromChapter1,examineshow
welltheyhavebeenmet,andcloseswithafewgeneralcommentsontheapproach.
8.1 Reviewoftherequirements
IwillnowwrapupourexplorationofPalimpsestbyrevisitingtherequirementslistedin
Section1.10,andseeingtowhatextentPalimpsestmeetsthem.Welisted9generalrequire-
mentsforflexibleconcurrencycontrolincollaborativework,andanadditional8require-
mentsformerge.Manyoftheserequirementsareinformal,inthesensethattheyadvocate
maximizationofsomegood,ratherthanmeetingtheidealofaformalrequirement:apredi-
catewhichisunambiguouslytrueorfalse.Inthissection,Ireviewsomeoftheserequire-
mentsandtheirrelationshiptothemodel,itsmotivatinganalysisandthetradeoffsmadein
theformaldefinition.Thisreexaminationconcentratesonthecoreissueofhowwellthere-
quirementsaremetbythemodel,butalsoconsiderstheminthelightofthespecificalgo-
rithmsandarchitecturesdiscussedinChapter6andChapter7.
Requirements1and2advocatesupportforbothsynchronousandasynchronouswork,as
wellasforfullyflexibletransitionsbetweenthem.Change-orientedconcurrencyworkswell