Carl Adam Petri: Life and Science

133 Pages·2015·3.96 MB·English

by  Einar Smith (auth.)

Einar Smith
Carl Adam Petri
Life and Science
Carl Adam Petri
CarlAdamPetri
Einar Smith
Carl Adam Petri
Life and Science
123
EinarSmith
Fraunhofer-GesellschaftSCAI-
InstituteforAlgorithmsandScientificComputing
SanktAugustin,Germany
TranslatedfromtheGermanbytheauthorandTimDenvir.
TitleoftheorginalGermanEdition:CarlAdamPetri-EineBiographie
©Springer-VerlagBerlinHeidelberg2014
ISBN978-3-662-48092-2 ISBN978-3-662-48093-9 (eBook)
DOI10.1007/978-3-662-48093-9
LibraryofCongressControlNumber:2015953838
SpringerHeidelbergNewYorkDordrechtLondon
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Foreword
Whoever had the privilege of meeting Carl Adam Petri in private or public
conversation remembers a very modest, humble person willing to patiently listen
to his guest. When it came to his view, however, he was an adamant visionary
who never allowed himself to sidetrack from his ultimate aim: to establish a
comprehensiveformalbasis forinformatics.In the cumbersomeage ofpapertape
and punched cards, Petri rightly predicted a central usage of today’s computing
devices in his PhD thesis, ‘Communication with Automata’. In times when only
stand-alone,one-processorcomputerswere available,Petrisuggestedconcurrency
asafundamentalphenomenonofdiscretelyevolvingsystems.
CarlAdamPetriisrenownedforhisinventionofwhatisknownas‘Petrinets’all
overtheworld,withplacestocontaintokensthataremovingalongtransitions.Petri
himselfconsideredthis conceptjusta starting pointfora far morecomprehensive
theory of informatics. During his professional life, Petri carefully observed the
quicklyevolvingworldofinformatics,fromitsinceptioninthe1950suntilthefirst
decade of the new millennium. He early envisaged some of the later outcomes;
othersheconsideredirrelevant.Healwayswasmissingacomprehensivediscussion
of the formal, theoretical basis of informatics. He never agreed with the narrative
ofadoptingtheconceptofcomputablefunctionsoversequencesofsymbolsasthe
onlyfundamentalbasisofinformatics,asfrequentlysuggested,inparticularduring
the hype of the ‘Turing year’, 2012. Instead, he had a clear vision of theoretical
concepts,inaccordancewiththelawsofphysics,informationflow,andinformation
processing.
Youmaywishtolearnmoreaboutthepersonwithsuchautonomousspirit.This
iswhatthisbookoffers:Aninspiringbiography,illuminatingboththepersonaland
theprofessionalevolutionofCarlAdamPetri.Knowledgeablereadersmayfindnew
perspectivesto Petrinets; otherreadersmaylearnwhatPetrinets areaboutin the
firstplace.
The author, Einar Smith, has been the most close collaborator and friend,
especiallyofthelateCarlAdamPetri.Nobodyelsecouldhavebetterselectedand
describedthehighlightsofPetri’slifeasascientist.
v
vi Foreword
I am very happy that Einar has compiled this text. This book adds valuable
insightsintoanexcitingaspectoftheshorthistoryofinformatics.Iwishthisbook
widerecognitionintheinformaticscommunityandbeyond.
Berlin,Germany WolfgangReisig
June2015
Preface
Carl Adam Petri passed away at the age of 83 in 2010. He spent most of his
professional life as head of institute in the Gesellschaft für Mathematik und
Datenverarbeitung(GMD,GermanNationalCenterforMathematicsandComputer
Science)inSanktAugustinnearBonn,Germany.
InrecognitionofhiscontributionstotheGMD,tobasicresearchincomputersci-
ence,andtocomputerscienceingeneral,themanagementboardoftheFraunhofer
Gesellschaft(in Englishknownas theFraunhoferInstitute),with whichthe GMD
merged in 2001, initiated a project to documentPetri’s life and works. Central to
thisprojectwasthepreparationofabiography.
I am very grateful that I was asked to undertake that task, because in this way
I got the opportunityto pass on at least a small part of what I have learned from
my revered teacher and friend Carl Adam. In innumerablelong conversations,he
explained to me, with great patience, his radical and visionary understanding of
informatics and computer science and showed me the route to my own research.
Also after his retirement, even when he was already heavily plagued by serious
illness,hecontinuedtosharehisinsightswithme.
TheworldwidedisseminationofthePetrinets,namedafterhim,hasdevelopeda
dynamic of its own; there is no end in sight, neither for theoretical research nor
practical applications. This gives me the opportunity to concentrate here on the
“historyofideas”behindtheoriginsandbackgroundofnetsandalsoontheperson
CarlAdamPetrihimself.
This historyincludesresearchinsightsandapproachesthathave influencednet
theory,eveniftheconnectionsarenotalwaysobvious.IfoneconsidersPetrinetsas
fungi,weshallthenbemainlyconcernedwiththegeneratingmycelium.
Themainguidelineweshallfollowisthechronologyoftheprincipalcharacter;
however,wheneverthecontentrequiresit,wegiveprecedencetoaclarificationof
thethoughtsandtheirinterrelations.
In compiling this biography, besides my own conversations with Carl Adam
Petri,thecontributionsofhisclosecollaboratorsHartmannGenrichandWolfgang
Reisig were also of great use. I am also very grateful for all the helpful personal
backgroundinformationthatCarlAdam’ssonTobiasgaveme.
IwasalsoabletoprofitextensivelyfromwrittencontributionsfromTobiasPetri,
who for instance has prepared an entire CD with data, stories, and photos of his
father. The text of a laudatory speech delivered by a colleague and friend of Carl
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Adam’s, Lu Ruqian from the Chinese Academy of Sciences, on the occasion of
Petri’s60thbirthdaywasalsoveryuseful.
The most important material was, however, a loose collection of more than
300 handwritten A4 pages that Petri perhaps intended to use himself in a future
autobiography.Where there were still some details missing, I made extensive use
of the Internet, to the development of whose predecessor, the ARPA-net, Petri
contributedinthe1960s.
This book is intended both for readers with previous knowledge in computer
science,whetherincludingPetrinetsornot,andfor“interestednonprofessionals,”
whomightperhapsdevelopaninterestina furtherstudyofPetrinets.Lastly,itis
alsointendedforreaderswhosimplywanttogettoknowaremarkablepersonality
of contemporary science. The text is organized in such a way that skipping over
formaldetailsshouldaffecttheoverallunderstandingaslittleaspossible.
The text is a slightly revised translation of the German original Carl Adam
Petri.EineBiographie,publishedbySpringer-Verlagin2014.Wheneveritseemed
necessary,however,Ihaveaddedadditionalnotesthatcouldbeusefultoreadersnot
familiarwithGermanyandtheGermanlanguage.
The translation was a two-phase process. First, I made a raw version myself,
which was then corrected and refined by a native English speaker, Tim Denvir, a
software engineer,computerscientist, and a regular consultantand bookreviewer
forSpringer.Infact,Denvir’scontributionswerenotlimitedtothelinguisticlevel.In
manycases,hiscriticalremarkshelpedmetoclarifytheformalargument.However,
Imyselfamresponsibleforanyremainingidiomaticidiosyncrasies.
ForfurtherstudiesofPetri’slifeandworks,thereaderisreferredtotheDeutsche
MuseuminMunich,wherePetri’sscientific estate,donatedbyhissonTobias,has
beenmeticulouslycuratedandarchived.TherePetriisinthebestofcompany,for
instancewithErnstMachandnotleastKonradZuse.
For stimulation and encouragement, I would in particular like to thank Tobias
PetriandWolfgangReisigfromtheHumboldtUniversity,Berlin.Iamalsograteful
toTobiasPetriforhispermissiontousedrawingsandphotographsfromhisfather’s
privatearchive.
Wolfgang has supportedthe publication energetically,not least by establishing
contactwithSpringer-Verlagandbyofferingtowriteaforeword.
Finally, I would like to thank all those involved at Springer-Verlag, especially
Hermann Engesser and Dorothea Glaunsinger, for their friendly and constructive
cooperation.
SanktAugustin,Germany EinarSmith
June2015
Contents
1 Introduction................................................................... 1
1.1 PetriNets ............................................................... 2
1.2 Concurrency,SequenceandConflict.................................. 3
1.3 TheFourSeasons....................................................... 4
1.4 DistributedAccess ..................................................... 5
1.5 Literature ............................................................... 6
1.6 ThePetriPuzzle........................................................ 7
2 InfancyandYouth............................................................ 9
2.1 Preschool ............................................................... 10
2.2 Machtergreifung:TheNazi’sSeizureofPower....................... 12
2.3 ElementarySchool..................................................... 12
2.4 GrammarSchool ....................................................... 13
2.5 FirstEncounterwiththeTheoryofKnowledge ...................... 13
2.6 NaturalSciences........................................................ 14
2.7 ArtilleryAssistant...................................................... 16
2.8 AirForce................................................................ 17
2.9 WarCaptivity........................................................... 18
3 University,Academe,Family................................................ 19
3.1 SchoolGraduation:Take3!............................................ 19
3.2 StudentYears........................................................... 21
3.3 HannoverComputerCenter............................................ 22
3.4 Family................................................................... 23
3.5 Bonn .................................................................... 27
4 ThesisonAutomata .......................................................... 29
4.1 CommunicationwithAutomata ....................................... 30
4.2 AlternativeApproaches................................................ 36
4.3 ImpactoftheThesis.................................................... 36
5 TheMaturingYears.......................................................... 39
5.1 AsynchronousInformationFlow...................................... 39
5.2 TheBonnComputerCenter............................................ 40
5.3 Israel.................................................................... 41
5.4 America................................................................. 42
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