A.W. Roscoe – författare

CSP notation has been used extensively for teaching and applying concurrency theory, ever since the publication of the text Communicating Sequential Processes by C.A.R. A first point of reference for anyone wanting to use CSP or learn about its theory, the book also introduces other views of concurrency, using CSP to model and explain these.

ThisvolumehasitsoriginsinameetingheldatMicrosoftResearch,Cambridge,in April2009tocelebrateTonyHoare's75thBirthday(actually11Jan2009). Allthe technicalpapersexceptforthosewrittenbyAbramsky,Jackson,JonesandMeyer arebased-sometimesclosely,sometimesnot-onpresentationsgivenatthatme- ing. TheideaforthemeetingaroseinconversationsbetweenourselvesandAndrew HerbertofMicrosoft,whohostedatrulymemorableandhappyevent. ThemeetingwasorganisedbyourselvesandKenWood,withthe?nancials- portofMicrosoftResearchandFormalSystems(Europe)Ltd,andheldovertwo days. We wouldlike to recordparticularthanksto Angela Still of Microsoftfor makingallthelocalarrangementsatCambridgeandmuchmore:themeetingwould nothavehappenedwithouther. Whilethemajorityofthepapersinthisvolumearetechnical,weaskedauthorsto re?ectonthein?uenceofHoare'sworkontheirown?eldsandtomakeappropriate remarksonit. Allthetechnicalpaperswererefereed. DiscussionswithWayneWheelerofSpringerinspiredthetwoofustowritethe scienti?cbiographyofHoarethatisthe?rstpaperinthisvolume. Thoughwehave bothknownTonywellformanyyears,wewereamazedathowmanydiscoveries abouthimwemadeduringtheprocessofwritingthisarticle.WewouldlikethankWayneandhisassistantSimonReesfortheirhelpinprep- ingthisvolumeaswellastheirpatience. Muchoftheworkingatheringthepapers, ensuringconsistencyofLaTeXstyles,etc. ,wasdonebyLucyLiofOxfordUniv- sityComputingLaboratoryandwethankherwarmly. Tragically,KenWood'swifeLisadiedafteralongillnessinSeptember2009. Wededicatethisvolumetohermemory. January2010 CliffJones BillRoscoe ix Contents 1 Insight,InspirationandCollaboration...1 C. B. JonesandA. W. Roscoe 2 FromCSPtoGameSemantics...33 SamsonAbramsky 3 OnMereologiesinComputingScience...47 DinesBjorner 4 Roles,Stacks,Histories:ATripleforHoare...71 Johannes Borgstrom, .. Andrew D. Gordon, andRiccardoPucella 5 ForwardwithHoare...101 MikeGordonandHel 'ene ' Collavizza 6 ProbabilisticProgrammingwithCoordination...123 HeJifeng 7 TheOperationalPrincipleandProblemFrames...143 MichaelJackson 8 TheRoleofAuxiliaryVariablesintheFormal DevelopmentofConcurrentPrograms...167 C. B. Jones 9 AvoidaVoid:TheEradicationofNullDereferencing...189 BertrandMeyer,AlexanderKogtenkov,andEmmanuelStapf 10 UnfoldingCSP...213 MikkelBundgaardandRobinMilner xi xii Contents 11 Quicksort:CombiningConcurrency,Recursion, andMutableDataStructures...229 DavidKitchin,AdrianQuark,andJayadevMisra 12 TheThousand-and-OneCryptographers...255 A. K. McIverandC. C. Morgan 13 On Process-AlgebraicExtensions of Metric TemporalLogic...283 ChristophHaase,Joel .. Ouaknine,andJamesWorrell 14 FunwithTypeFunctions...301 OlegKiselyov,SimonPeytonJones,andChung-chiehShan 15 OnCSPandtheAlgebraicTheoryofEffects...333 RobvanGlabbeekandGordonPlotkin 16 CSPisExpressiveEnoughfor ...371 A. W. Roscoe 17 TheTokeneerExperiments...405 JimWoodcock,EmineGokc .. ,eAydal,andRodChapman Chapter1 Insight,InspirationandCollaboration C. B. JonesandA. W. Roscoe Abstract TonyHoare'smanycontributionstocomputingsciencearemarkedby insightthatwasgroundedinpracticalprogramming. Manyofhispapershavehada profoundimpactontheevolutionofour?eld;theyhavemoreoverprovidedasource ofinspirationtoseveralgenerationsofresearchers. Weexaminethedevelopmentof hisworkthroughareviewofthedevelopmentofsomeofhismostin?uentialpieces ofworksuchasHoarelogic,CSPandUnifyingTheories. 1. 1 Introduction To many who know Tony Hoare only through his publications, they must often looklikepolishedgemsthatcomefromamindthatrarelymakesfalsesteps,nor evenperhapshastoworkattheircreation.Assooften,thisimpressionisafurther complimenttosomeonewhoactuallyaddstoveryhardworkandmanydiscarded attempts the ?nal polish thatmakes complexideas relatively easy for the reader tocomprehend. Asindicatedonpagexiof[HJ89],hisideastypicallygothrough manyrevisions. ThetwoauthorsofthecurrentpapereachhadthehonourofTonyHoaresuperv- ingtheirdoctoralstudiesinOxford. Theyknowat?rsthandhiskindandgenerous styleandwillcountitasanachievementifthispapercanconveysomethingofthe workingmethodsofsomeonebigenoughtoeschewcompetitionandpointscoring. Indeedit willbe apparentfromthe followingsectionshowoften,havingstarted somenewwayofthinkingorexcitingideas,hehappilyleavestheirexplorationand developmenttoothers. Wehavebothbene?tedpersonallyfromthis. C. B. Jones( ) SchoolofComputingScience,NewcastleUniversity,UK e-mail:cliff. jones@ncl. ac. uk A. W. Roscoe OxfordUniversityComputingLaboratory,UK e-mail:Bill. Roscoe@comlab. ox. ac. uk C. B. Jonesetal. (eds. ),Re?ectionsontheWorkofC. A. R.

Since the introduction of Hoares' Communicating Sequential Processes notation, powerful new tools have transformed CSP into a practical way of describing industrial-sized problems. This book presents the fundamental knowledge of CSP concepts readers require to take advantage of those tools. This text benefits from the author's ten years of teaching experience to guide the reader through an introductory course on the theory and practice of concurrency. The book is divided into three parts; the first begins with an introductory course into the theories behind computer concurrency. The second part summarises the main ideas and results featuring chapters on advanced specification techniques, buffer tolerance, induction and data independence. The final part focuses on practice, containing chapters on the bully algorithms and deadlock. Bridging the gap between theory and practice, this logical and practical guide provides readers with in-depth examples explained, and shown in practice.