Fault Tolerant PVM Application A Case Study with DCICADA(FT).pdf

FaultTolerantPVMApplication?—ACaseStudywith  D-CICADA(FT) (Extendedabstract) LudˇekMatyskaandKarelTaft DepartmentofInformationTechnology FacultyofInformatics,MasarykUniversity Bureˇsova20,60200Brno,CzechRepublic e-mail: fludekktaftginfor mati csm uni cz September14,1994 Motivation Theeverincreasingnumberofcomputersconnectedintonetworkleadstothedevelopment ofnewprogrammingtechniquestoallowfulluseofthepotentialofthese virtualcomput- ers.Despiteproblemsofprogrammingdifficulty,associatedwiththedistributedcomputing environment,theproblemoffaulttolerance isalsoemerging.Thedistributedcomputingen- vironmentisoftenusedasalow-costsubstituteoffast(super)computers.However,thevery natureofthesevirtualcomputers,createdfromdozensofordinaryworkstationsinlocalor metropolitanareanetworks,isnotreallysuitableforlongtimetasks.Congestioninthenet- work,softwareandhardwarecrashes,brokenconnectionsetcareallthereasonswhilethe efficientuseofthevirtualcomputerisfurthercomplicated.Toeaseitsuse,modifiedand/or newtoolsandtechniquesmustbeprovided,bothatthelevelofdistributedcomputingenvi- ronmentandatthelevelofprogrammingmethodology. Inthisarticle,D-CICADA(FT),arobustimplementationoftheD-CICADAsystem[1]is presented. Itisshownhowcarefuldesignmayleadtorobust(andalmostfaulttolerant) system. D-CICADA:master—slaveprogrammingmodel D-CICADAisthedistributedimplementationofthemethodforanalysisofpotentialen- ergyhypersurfaces(PES)ofmolecules. Itsearchesforthelowenergyconformationsand pathsbetweenthem.Itusesdriverapproach,rotatingallpredefinedtorsionsinalldirections. D-CICADAusesanotionofdrivingpathasasequenceofdrivingstepsleadingfromamini-