Peter Landin Semantics Seminar 2020 Algol 60 @ 60
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Kathleen Fisher Question: Interesting Answer in Algol
10/21/08 cs242! Lisp! Algol 60! Algol 68! Pascal! Kathleen Fisher! ML! Modula! Reading: “Concepts in Programming Languages” Chapter 5 except 5.4.5! Haskell! “Real World Haskell”, Chapter 0 and Chapter 1! (http://book.realworldhaskell.org/)! Many other languages:! Algol 58, Algol W, Euclid, EL1, Mesa (PARC), …! Thanks to John Mitchell and Simon Peyton Jones for some of these slides. ! Modula-2, Oberon, Modula-3 (DEC)! Basic Language of 1960! Simple imperative language + functions! Successful syntax, BNF -- used by many successors! real procedure average(A,n); statement oriented! real array A; integer n; No array bounds.! begin … end blocks (like C { … } )! begin if … then … else ! real sum; sum := 0; Recursive functions and stack storage allocation! for i = 1 step 1 until n Fewer ad hoc restrictions than Fortran! do General array references: A[ x + B[3] * y ] sum := sum + A[i]; Type discipline was improved by later languages! average := sum/n No “;” here.! Very influential but not widely used in US! end; Tony Hoare: “Here is a language so far ahead of its time that it was not only an improvement on its predecessors Set procedure return value by assignment.! but also on nearly all of its successors.”! Question:! Holes in type discipline! Is x := x equivalent to doing nothing?! Parameter types can be arrays, but! No array bounds! Interesting answer in Algol:! Parameter types can be procedures, but! No argument or return types for procedure parameters! integer procedure p; begin Problems with parameter passing mechanisms! -
Thomas Ströhlein's Endgame Tables: a 50Th Anniversary
Thomas Ströhlein's Endgame Tables: a 50th Anniversary Article Supplemental Material The Festschrift on the 40th Anniversary of the Munich Faculty of Informatics Haworth, G. (2020) Thomas Ströhlein's Endgame Tables: a 50th Anniversary. ICGA Journal, 42 (2-3). pp. 165-170. ISSN 1389-6911 doi: https://doi.org/10.3233/ICG-200151 Available at http://centaur.reading.ac.uk/90000/ It is advisable to refer to the publisher’s version if you intend to cite from the work. See Guidance on citing . Published version at: https://content.iospress.com/articles/icga-journal/icg200151 To link to this article DOI: http://dx.doi.org/10.3233/ICG-200151 Publisher: The International Computer Games Association All outputs in CentAUR are protected by Intellectual Property Rights law, including copyright law. Copyright and IPR is retained by the creators or other copyright holders. Terms and conditions for use of this material are defined in the End User Agreement . www.reading.ac.uk/centaur CentAUR Central Archive at the University of Reading Reading’s research outputs online 40 Jahre Informatik in Munchen:¨ 1967 – 2007 Festschrift Herausgegeben von Friedrich L. Bauer unter Mitwirkung von Helmut Angstl, Uwe Baumgarten, Rudolf Bayer, Hedwig Berghofer, Arndt Bode, Wilfried Brauer, Stephan Braun, Manfred Broy, Roland Bulirsch, Hans-Joachim Bungartz, Herbert Ehler, Jurgen¨ Eickel, Ursula Eschbach, Anton Gerold, Rupert Gnatz, Ulrich Guntzer,¨ Hellmuth Haag, Winfried Hahn (†), Heinz-Gerd Hegering, Ursula Hill-Samelson, Peter Hubwieser, Eike Jessen, Fred Kroger,¨ Hans Kuß, Klaus Lagally, Hans Langmaack, Heinrich Mayer, Ernst Mayr, Gerhard Muller,¨ Heinrich Noth,¨ Manfred Paul, Ulrich Peters, Hartmut Petzold, Walter Proebster, Bernd Radig, Angelika Reiser, Werner Rub,¨ Gerd Sapper, Gunther Schmidt, Fred B. -
Computing Versus Human Thinking
By Peter Naur, recipient of ACM’s 2005 A.M. Turing Award Computing Versus Human Thinking n this presentation I shall give you an overview of efforts. Indeed, I have found that a large part of what Imy works from the past fifty years concerning the is currently said about human thinking and about sci- issue given in the title. Concerning this title I entific and scholarly activity is false and harmful to invite you to note particularly the middle word, ‘ver- our understanding. I realize that my presentation of sus’. This word points to the tendency of my efforts some of these issues may be offensive to you. This I around this theme, to wit, to clarify the contrast regret, but it cannot be avoided. between the two items, computing and human thinking. This tendency of my work has found its DESCRIPTION AS THE CORE ISSUE OF SCIENCE AND ultimate fulfilment in my latest result, which is a SCHOLARSHIP description of the nervous system showing that this The tone of critique and rejection of established system has no similarity whatever to a computer. ideas has its roots in my earliest activity, from its very It is ironic that my present award lecture is given beginning more than fifty years ago. Already in my under the title of Turing. As a matter of fact, one part work in astronomy, around 1955, a decisive item in of my work concerning computing and human think- my awareness came from Bertrand Russell’s explicit ing has been an explicit critique, or rejection, of the rejection of any notion of cause as a central issue of ideas of one prominent contribution from Alan Tur- scientific work. -
A Universal Modular ACTOR Formalism for Artificial
Artificial Intelligence A Universal Modular ACTOR Formalism for Artificial Intelligence Carl Hewitt Peter Bishop Richard Steiger Abstract This paper proposes a modular ACTOR architecture and definitional method for artificial intelligence that is conceptually based on a single kind of object: actors [or, if you will, virtual processors, activation frames, or streams]. The formalism makes no presuppositions about the representation of primitive data structures and control structures. Such structures can be programmed, micro-coded, or hard wired 1n a uniform modular fashion. In fact it is impossible to determine whether a given object is "really" represented as a list, a vector, a hash table, a function, or a process. The architecture will efficiently run the coming generation of PLANNER-like artificial intelligence languages including those requiring a high degree of parallelism. The efficiency is gained without loss of programming generality because it only makes certain actors more efficient; it does not change their behavioral characteristics. The architecture is general with respect to control structure and does not have or need goto, interrupt, or semaphore primitives. The formalism achieves the goals that the disallowed constructs are intended to achieve by other more structured methods. PLANNER Progress "Programs should not only work, but they should appear to work as well." PDP-1X Dogma The PLANNER project is continuing research in natural and effective means for embedding knowledge in procedures. In the course of this work we have succeeded in unifying the formalism around one fundamental concept: the ACTOR. Intuitively, an ACTOR is an active agent which plays a role on cue according to a script" we" use the ACTOR metaphor to emphasize the inseparability of control and data flow in our model. -
Edsger Dijkstra: the Man Who Carried Computer Science on His Shoulders
INFERENCE / Vol. 5, No. 3 Edsger Dijkstra The Man Who Carried Computer Science on His Shoulders Krzysztof Apt s it turned out, the train I had taken from dsger dijkstra was born in Rotterdam in 1930. Nijmegen to Eindhoven arrived late. To make He described his father, at one time the president matters worse, I was then unable to find the right of the Dutch Chemical Society, as “an excellent Aoffice in the university building. When I eventually arrived Echemist,” and his mother as “a brilliant mathematician for my appointment, I was more than half an hour behind who had no job.”1 In 1948, Dijkstra achieved remarkable schedule. The professor completely ignored my profuse results when he completed secondary school at the famous apologies and proceeded to take a full hour for the meet- Erasmiaans Gymnasium in Rotterdam. His school diploma ing. It was the first time I met Edsger Wybe Dijkstra. shows that he earned the highest possible grade in no less At the time of our meeting in 1975, Dijkstra was 45 than six out of thirteen subjects. He then enrolled at the years old. The most prestigious award in computer sci- University of Leiden to study physics. ence, the ACM Turing Award, had been conferred on In September 1951, Dijkstra’s father suggested he attend him three years earlier. Almost twenty years his junior, I a three-week course on programming in Cambridge. It knew very little about the field—I had only learned what turned out to be an idea with far-reaching consequences. a flowchart was a couple of weeks earlier. -
Technical Details of the Elliott 152 and 153
Appendix 1 Technical Details of the Elliott 152 and 153 Introduction The Elliott 152 computer was part of the Admiralty’s MRS5 (medium range system 5) naval gunnery project, described in Chap. 2. The Elliott 153 computer, also known as the D/F (direction-finding) computer, was built for GCHQ and the Admiralty as described in Chap. 3. The information in this appendix is intended to supplement the overall descriptions of the machines as given in Chaps. 2 and 3. A1.1 The Elliott 152 Work on the MRS5 contract at Borehamwood began in October 1946 and was essen- tially finished in 1950. Novel target-tracking radar was at the heart of the project, the radar being synchronized to the computer’s clock. In his enthusiasm for perfecting the radar technology, John Coales seems to have spent little time on what we would now call an overall systems design. When Harry Carpenter joined the staff of the Computing Division at Borehamwood on 1 January 1949, he recalls that nobody had yet defined the way in which the control program, running on the 152 computer, would interface with guns and radar. Furthermore, nobody yet appeared to be working on the computational algorithms necessary for three-dimensional trajectory predic- tion. As for the guns that the MRS5 system was intended to control, not even the basic ballistics parameters seemed to be known with any accuracy at Borehamwood [1, 2]. A1.1.1 Communication and Data-Rate The physical separation, between radar in the Borehamwood car park and digital computer in the laboratory, necessitated an interconnecting cable of about 150 m in length. -
An Early Program Proof by Alan Turing F
An Early Program Proof by Alan Turing F. L. MORRIS AND C. B. JONES The paper reproduces, with typographical corrections and comments, a 7 949 paper by Alan Turing that foreshadows much subsequent work in program proving. Categories and Subject Descriptors: 0.2.4 [Software Engineeringj- correctness proofs; F.3.1 [Logics and Meanings of Programs]-assertions; K.2 [History of Computing]-software General Terms: Verification Additional Key Words and Phrases: A. M. Turing Introduction The standard references for work on program proofs b) have been omitted in the commentary, and ten attribute the early statement of direction to John other identifiers are written incorrectly. It would ap- McCarthy (e.g., McCarthy 1963); the first workable pear to be worth correcting these errors and com- methods to Peter Naur (1966) and Robert Floyd menting on the proof from the viewpoint of subse- (1967); and the provision of more formal systems to quent work on program proofs. C. A. R. Hoare (1969) and Edsger Dijkstra (1976). The Turing delivered this paper in June 1949, at the early papers of some of the computing pioneers, how- inaugural conference of the EDSAC, the computer at ever, show an awareness of the need for proofs of Cambridge University built under the direction of program correctness and even present workable meth- Maurice V. Wilkes. Turing had been writing programs ods (e.g., Goldstine and von Neumann 1947; Turing for an electronic computer since the end of 1945-at 1949). first for the proposed ACE, the computer project at the The 1949 paper by Alan M. -
The Advent of Recursion & Logic in Computer Science
The Advent of Recursion & Logic in Computer Science MSc Thesis (Afstudeerscriptie) written by Karel Van Oudheusden –alias Edgar G. Daylight (born October 21st, 1977 in Antwerpen, Belgium) under the supervision of Dr Gerard Alberts, and submitted to the Board of Examiners in partial fulfillment of the requirements for the degree of MSc in Logic at the Universiteit van Amsterdam. Date of the public defense: Members of the Thesis Committee: November 17, 2009 Dr Gerard Alberts Prof Dr Krzysztof Apt Prof Dr Dick de Jongh Prof Dr Benedikt Löwe Dr Elizabeth de Mol Dr Leen Torenvliet 1 “We are reaching the stage of development where each new gener- ation of participants is unaware both of their overall technological ancestry and the history of the development of their speciality, and have no past to build upon.” J.A.N. Lee in 1996 [73, p.54] “To many of our colleagues, history is only the study of an irrele- vant past, with no redeeming modern value –a subject without useful scholarship.” J.A.N. Lee [73, p.55] “[E]ven when we can't know the answers, it is important to see the questions. They too form part of our understanding. If you cannot answer them now, you can alert future historians to them.” M.S. Mahoney [76, p.832] “Only do what only you can do.” E.W. Dijkstra [103, p.9] 2 Abstract The history of computer science can be viewed from a number of disciplinary perspectives, ranging from electrical engineering to linguistics. As stressed by the historian Michael Mahoney, different `communities of computing' had their own views towards what could be accomplished with a programmable comput- ing machine. -
Software Tools: a Building Block Approach
SOFTWARE TOOLS: A BUILDING BLOCK APPROACH NBS Special Publication 500-14 U.S. DEPARTMENT OF COMMERCE National Bureau of Standards ] NATIONAL BUREAU OF STANDARDS The National Bureau of Standards^ was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to pro- mote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology, the Institute for Computer Sciences and Technology, the Office for Information Programs, and the ! Office of Experimental Technology Incentives Program. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consist- ent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essen- tial services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of the Office of Measurement Services, and the following center and divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical Physics — Center for Radiation Research — Lab- oratory Astrophysics^ — Cryogenics^ — Electromagnetics^ — Time and Frequency*. THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to improved methods of measure- ment, standards, and data on the properties of well-characterized materials needed by industry, commerce, educational insti- tutions, and Government; provides advisory and research services to other Government agencies; and develops, produces, and distributes standard reference materials. -
Edsger W. Dijkstra: a Commemoration
Edsger W. Dijkstra: a Commemoration Krzysztof R. Apt1 and Tony Hoare2 (editors) 1 CWI, Amsterdam, The Netherlands and MIMUW, University of Warsaw, Poland 2 Department of Computer Science and Technology, University of Cambridge and Microsoft Research Ltd, Cambridge, UK Abstract This article is a multiauthored portrait of Edsger Wybe Dijkstra that consists of testimo- nials written by several friends, colleagues, and students of his. It provides unique insights into his personality, working style and habits, and his influence on other computer scientists, as a researcher, teacher, and mentor. Contents Preface 3 Tony Hoare 4 Donald Knuth 9 Christian Lengauer 11 K. Mani Chandy 13 Eric C.R. Hehner 15 Mark Scheevel 17 Krzysztof R. Apt 18 arXiv:2104.03392v1 [cs.GL] 7 Apr 2021 Niklaus Wirth 20 Lex Bijlsma 23 Manfred Broy 24 David Gries 26 Ted Herman 28 Alain J. Martin 29 J Strother Moore 31 Vladimir Lifschitz 33 Wim H. Hesselink 34 1 Hamilton Richards 36 Ken Calvert 38 David Naumann 40 David Turner 42 J.R. Rao 44 Jayadev Misra 47 Rajeev Joshi 50 Maarten van Emden 52 Two Tuesday Afternoon Clubs 54 2 Preface Edsger Dijkstra was perhaps the best known, and certainly the most discussed, computer scientist of the seventies and eighties. We both knew Dijkstra |though each of us in different ways| and we both were aware that his influence on computer science was not limited to his pioneering software projects and research articles. He interacted with his colleagues by way of numerous discussions, extensive letter correspondence, and hundreds of so-called EWD reports that he used to send to a select group of researchers. -
A Common Programming Language for the Depart Final Ment of Defenses-Background and Technical January -December 1975 1 Requirements «
Approved for public release; distribution unlimited I 1 PAPER P-1191 A COMMON PROGRAMMING LANGUAGE 1 FOR THE DEPARTMENT OF DEFENSE - - I BACKGROUND AND TECHNICAL REQUIREMENTS I I D. A. Fisher June 1976 I 1 I I I I INSTITUTE FOR DEFENSE ANALYSES I SCIENCE AND TECHNOLOGY DIVISION I I IDA Log No. HQ 76-18215 I Cop-)*- > . -JJ . of 155. cop I ess Approved for public release; distribution unlimited I I I I The work reported in this document was conducted under contract DAHC15 73 C 0200 for the Department of Defense. The publication I of this IDA Paper does not indicate endorsement by the Department of Defense, nor should the contents be construed as reflecting the official position of that agency. I I I I This document has been approved for public release, distribution is unlimited. I I 1 1 1 I I I Copyright IDA/Scanned June 2007 I 1 Approved for public release; distribution unlimited UNCLASSIFIED - ©; ; ; : ;" -; .©, . 1 SECURITY CLASSIFICATION OF THIS PAGE CWnen DM* Entered; READ INSTRUCTIONS REPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM ). RECIPIENT©S CATALOG NUMBER 1 Paper P-J.191. 4. TITLE fend Subtitle.) 5. TYPE Of REPORT e PERIOD COVERED A Common Programming Language for the Depart Final ment of Defenses-Background and Technical January -December 1975 1 Requirements «. PERFORMING ORG. REPORT NUMBER P-1191 I. CONTRACT OR GRANT NUMBERflJ 1 DAHC15 73 C 0200 D.A, Fisher 10. PROGRAM ELEMENT. PROJECT TASK 1 INSTITUTE FOR DEFENSE ANALYSES AREA * WORK UNIT NUMBERS 400 Army-Navy Drive Task T-36 Arlington. Virginia 22202 11. -
Computer Conservation Society
Computer Conservation Society Aims and objectives The Computer Conservation Society (CCS) is a co-operative venture between the British Computer Society, the Science Museum of London and the Museum of Science and Industry in Manchester. The CCS was constituted in September 1989 as a Specialist Group of the British Computer Society (BCS). It is thus covered by the Royal Charter and charitable status of the BCS. The aims of the CCS are to Promote the conservation of historic computers and to identify existing computers which may need to be archived in the future Develop awareness of the importance of historic computers Encourage research on historic computers and their impact on society Membership is open to anyone interested in computer conservation and the history of computing. The CCS is funded and supported by voluntary subscriptions from members, a grant from the BCS, fees from corporate membership, do- nations, and by the free use of Science Museum facilities. Some charges may be made for publications and attendance at seminars and conferences. There are a number of active Working Parties on specific computer restorations and early computer technologies and software. Younger peo- ple are especially encouraged to take part in order to achieve skills transfer. Resurrection The Bulletin of the Computer Conservation Society ISSN 0958 - 7403 Number 30 Spring 2003 Contents Generous BCS Support for Bombe Rebuild Project Ernest Morris, Chairman 2 AGM 2 News Round-Up 3 Society Activity 6 CCS Collection Policy 11 DAP snippets Brian M Russell 12 CCS Web Site Information 12 British Computer Corporation | a 1956 Venture Hugh McGregor Ross 13 Edsger Dijkstra remembered Brian Shearing 22 Deciphering Ancient Floppy Discs Kevin Murrell 26 The ICL Archive Hamish Carmichael 28 Forthcoming Events 31 Generous BCS Support for Bombe Rebuild Project Ernest Morris, Chairman CCS members will be familiar with the good progress of the Bombe re- build from the regular reports in Resurrection by John Harper, the project manager.