SDC: Q-32 Lisp, Lisp 2, and three more; Lisp 1.5 Primer

Lisp’s birth and infancy was at MIT, but it began spreading to other places when John McCarthy went to Stanford and other project members graduated and moved on. At about this time, a project began to develop a new language, Lisp 2, that would extend Lisp to include ALGOL-like syntax, type-checking, and numeric, string, and array data types. The project was a joint development of two “think tanks”, Information International, Inc. (III) System Development Corporation (SDC) in Santa Monica, California.

The host computer for the Lisp 2 project was the AN/FSQ-32/V, a one-of-a-kind prototype built by IBM for the Air Force as a potential replacements for the SAGE AN/FSQ-7. Before the Lisp 2 project began, an innovative compiler-only implementation of Lisp 1.5 on the Q-32 was done by Robert Saunders and his colleagues.

Through the kindness of Jeff Barnett, who was one of central contributors at SDC, the History of LISP web site now includes scanned copies of the Lisp 2 source code (with annotations by Jeff) and a number of documents, including the complete TM-3417 series documenting a planned (but not completed) port to the IBM System/360. A few other early memos were previously available online as MIT Project Mac memos. Additional memos will be soon be available via the Stoyan collection.

After the Lisp 2 project was terminated, the Q-32 at SDC was replaced with an IBM System/360. The researchers still wanted to use Lisp, so Jeff Barnett and Bob Long implemented a Lisp 1.5 for the System/360. Again, Jeff loaned a copy of the original manual and also wrote new notes.

Speech understanding was a major research area for many people at SDC, including Jeff. As building blocks for the speech research, he worked on two more Lisp or Lisp-like systems:

  1. A small Lisp for the Raytheon 704 used for speech capture and low-level processing.
  2. The Crisp Lisp 2-like system for the IBM System/370.

Jeff has provided modern notes for both, and for Crisp both the original documentation as well as slides from a recent talk he gave.

Finally, another offshoot of the Lisp 2 project is the book LISP 1.5 Primer by Clark Weissman. It began as a tutorial to help SDC researchers learn Lisp, and in 1967 was published as a book by Dickenson Publishing Company, Inc., of Belmont, California. The book has long been out of print and the copyright reverted to Clark; he has given his permission for a PDF of the book to be posted on the History of LISP web site.

Update 11/26/2010: Updated URLs to reflect reorganization of

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Herbert Stoyan’s Lisp collection at CHM

Last winter Herbert Stoyan very generously donated to the Computer History Museum the extensive collection of Lisp and AI materials he assembled in the course of his extensive study of Lisp and its history: manuals, technical reports, papers, books, listings, magnetic media, and even two Scheme chips.

Stoyan has been involved with Lisp for four decades. In the early 1970s he implemented Lisp using only Berkeley and Bobrow as a reference, and this system became the basis for all artificial intelligence work in his native East Germany. In the late 1970s he became interested in the history of Lisp, and published the book LISP – Anwendungsgebiete, Grundbegriffe, Geschichte (Akademie-Verlag, Berlin, 1980) about Lisp and its history. In 1981 he emigrated to West Germany and began a career as a university professor; by 1990 he became Professor of Artificial Intelligence of the Friedrich-Alexander-Universität Erlangen-Nürnberg. He also wrote the two-volume Programmiermethoden der Künstlichen Intelligenz (Springer, 1988) about artificial intelligence programming. (For more details, see his speaker biography from the 2007 International Lisp Conference.)

In addition to his first book, Stoyan has published a number of papers on the early history of Lisp, including:

The Herbert Stoyan Collection on LISP Programming (Lot X5687.2010) is quite large (94.5 linear feet in 87 boxes), and the Museum is currently in the throws of construction for the major new exhibit Revolution: The First 2000 Years of Computing. But through the combined efforts of staff and volunteers, the collection will be organized and made accessible, with portions scanned and available online. To get a taste of the depth and breadth of the collection, see Stoyan’s LISP Bibliography and searchable LISP-Museum.

The arrival of this collection at CHM fulfills a dream that began for me in 2005 as I began work on History of LISP and first contacted Herbert Stoyan to timidly suggest he might contribute scans of selected items from his collection to CHM. His response — that he would be retiring in 3 years and needed to think about a permanent home for his collection — encouraged me to think that CHM might be the recipient. To get here from there, many people played important roles. At the risk of forgetting someone, I would like to thank Alex Bochannek, Grady Booch, Elizabeth Borchardt, Richard Gabriel, William Harnack, John Hollar, Paul Jabloner, Al Kossow, Karen Kroslowitz, Sara Lott, Bernard Peuto, Len Shustek, Dag Spicer, Herbert Stoyan, Kirsten Tashev, and JonL White. In addition, CHM volunteers John Dobyns and Randall Neff have labored to survey, pack, and catalog portions of the collection. (Additional volunteers would be welcome!)

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Bob Taylor on CHM’s YouTube channel

Bob Taylor was the featured guest at a recent Computer History Museum event: “Net@40: Robert W. Taylor in Conversation with Guy Raz”. The video of that event is now online. (See here and here for earlier postings about Bob on this blog.)

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Whetstone ALGOL

Part of my motivation for starting on an ALGOL project was that Brian Randell recently obtained permission from the copyright holder to post an online copy of ALGOL 60 Implementation at CHM. This book, which he and Lawford Russell published in 1964, provides a detailed description of the ALGOL 60 compiler (known as Whetstone ALGOL) they developed for the English Electric KDF9 Computer. In January, Brian gave a talk “Reminiscences of Whetstone ALGOL” at a joint meeting of the BCS Advanced Programming Group and the Computer Conservation Society recognizing the 50th anniversary of ALGOL 60; see here for more on Whetstone. In particular, the Whetstone Algol resurrection team notes: “We now have the Walgol Translator re-keyed from a dog-eared listing, in the main, by Brian Wichmann, Graham Toal and Roderick McLeod. David Holdsworth has written an assembler and a rough-and-ready emulator. Bill Findlay is in the process of implementing a properly-enginered emulator.”

Update 7/11/2012: corrected URLs for ALGOL 60 Implementation at Software Preservation Group website and “Reminiscences of Whetstone ALGOL” at

Update 9/22/2010: corrected URL for Whetstone at Software Preservation Group website.

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I recently created an ALGOL section at the Computer History Museum‘s Software Preservation Group web site, covering the language standardization efforts — for ALGOL 58 (also known as the International Algebraic Language), ALGOL 60, and ALGOL 68 — and also covering many implementations, dialects, and offshoots, complete with source code, manuals, and papers for many of these. The history of ALGOL has attracted many writers, and the final section of the web site links to many of their papers.

The ALGOL 58/60 implementations for which I’ve been able to find source code for include:

  • Burroughs 205 (Knuth)
  • Burroughs 220 (Erdwinn et al.)
  • Burroughs B-5500
  • DEC PDP-10 (Habermann et al.)
  • Electrologica X1 (Dijkstra and Zonneveld – Mathematisch Centrum)
  • Electrologica X8 (Kruseman Aretz – Mathematisch Centrum)
  • Electrologica X8 (Bron et al. – Technische Hogeschool Eindhoven)
  • Elliot 803 (Hoare et al.)
  • English Electric Whetstone (Randell and Russell)
  • G.E.C. process control computer (Higman)
  • Regnecentralen GIER (Naur et al.)
  • Stantec Zebra (van der Mey – Netherlands PTT)

The appendices to Maurice Halstead’s book Machine-Independent Programming (Spartan Books, 1962) contain compiler source listings of Neliac (an ALGOL 58 dialect) for the UNIVAC M-460, IBM 704, and CDC 1604.

I also found compiler source code and listings for several versions of ALGOL W.

I’ve just gotten started looking for ALGOL 68 implementations.

I welcome your comments, corrections, and suggestions for the ALGOL web site.

Posted in ALGOL, Software history | 8 Comments

Don Chamberlin and the origin of SQL

Tonight Don Chamberlin will receive a 2009 Fellow Award of the Computer History Museum “for his fundamental work on structured query language (SQL) and database architectures”. The other awardees for 2009 are Robert R. Everett (M.I.T. Whirlwind and SAGE) and Federico Faggin, Marcian (Ted) Hoff, Stanley Mazor and Masatoshi Shima (Intel 4004).

In a recent oral history I conducted for the Computer History Museum, Don put into context his work designing SQL in collaboration with Ray Boyce. Don described the pre-relational database management systems, Ted Codd’s development of the relational model, various implementation projects at IBM culminating in System R, which was the first RDBMS to support SQL. Don went on to describe other pioneering relational systems, including Ingres and Oracle. He also described his subsequent work on text processing, DB/2, and XQuery.

For further historical information about Don and his work, see:

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Bob Taylor recognized by The University of Texas

Last month, Bob Taylor (the subject of a recent oral history) was recognized by The University of Texas. Bob received the Graduate School Outstanding Alumnus Award, a $100,000 Presidential Endowed Fellowship was established in his name, and he gave the first in a series of lectures in the UT Graduate School’s Centential celebration. Since this is also the 40th anniversary of the first tests of the ARPAnet, it was a fitting time for Bob’s achievements to be honored.

The lecture was in the form of an interview by New York Times technology reporter John Markoff, who noted:

The Internet has many fathers, but few deserve the label more than Robert W. Taylor.

Authors M. Mitchell Waldrop (The Dream Machine) and Michael A. Hiltzik (Dealers of Lightning: Xerox PARC and the Dawn of the Computer Age) shared their views as well. J Strother Moore and Gary Chapman (who each worked with Bob in the past and now have UT positions) served as masters of ceremony.

The announcement for the lecture includes links to news stories about Bob, as well as the famous 1968 paper by Licklider and Taylor, “The Computer as a Communication Device”. The recap of the lecture includes links to a video and photographs.

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WIRED appreciates FORTRAN

WIRED‘s THIS DAY IN TECH feature for tomorrow is
Oct. 15, 1956: Fortran Forever Changes Computing’s Fortunes.

The article links to the Software Preservation Group FORTRAN web site and uses a photograph of John Backus and John Cocke from a souvenir matchbook cover from Capt. Starn’s Restaurant and Bar in Atlantic City, New Jersey, year unknown:

John Backus and John Cocke at Capt' Starn's Restaurant and Bar, Atlantic City, New Jersey

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Elements of Programming

Elements of Programming, by Alexander Stepanov and Paul McJones, was published this month by Addison-Wesley Professional. From the preface:

This book applies the deductive method to programming by affiliating programs with the abstract mathematical theories that enable them to work. Specification of these theories, algorithms written in terms of these theories, and theorems and lemmas describing their properties are presented together. The implementation of the algorithms in a real programming language is central to the book. While the specifications, which are addressed to human beings, should, and even must, combine rigor with appropriate informality, the code, which is addressed to the computer, must be absolutely precise even while being general.

The roots of the book go back many years. In 1976 Alex had two important revelations: an essential part of programming is to find the most general form of each algorithmic component and, as he wrote a few years ago, “Our ability to restructure certain computations to be done in parallel depends on the algebraic properties of operations. For example, we can re-order a + (b + (c + d)) into (a + b) + (c + d) because addition is associative.” Much of his subsequent career, including his development of the C++ Standard Template Library, can be described as pursuing the consequences of these ideas.

I met Alex in early 2003, shortly after each of us joined Adobe Systems. As I mentioned in an earlier post, we discovered a common connection, to John Backus. Our first collaboration was co-chairing a company-wide internal engineering conference in 2004. After that I began attending the course on Foundations of Programming that Alex was teaching at Adobe. In 2005, I joined Alex in the Software Technology Lab, which was led by our colleague Sean Parent. In 2007, Alex invited me to work with him on converting his course notes into a book. We soon concluded that a fresh start was necessary. About two years later, Elements of Programming was complete.

The code in the book can be downloaded from the companion web site.

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Oral history of Robert W. Taylor

Robert W. Taylor directed external research at NASA, where he funded early work by Douglas Engelbart, and at the ARPA IPTO, where he initiated the ARPANET project. He also founded the Xerox PARC Computer Science Laboratory and later the DEC Systems Research Center. Last fall I interviewed him for the Computer History Museum‘s Oral History Collection. The transcript, based on two afternoons of interviewing captured on six videotapes, has been edited and is now online: catalog entry; transcript (PDF).

Here are summaries of the contents (corresponding to the six videotapes):

  1. Taylor’s childhood, education, military service in the US Navy during the Korean War, and his first positions after graduating from college: teaching at a prep school in Florida, and systems engineering at The Martin Company in Orlando, Florida; managing research at NASA and at ARPA IPTO.
  2. The ARPANET project, the founding of the graphics work at the University of Utah; his own brief stay at the University of Utah; the founding and early history of the Xerox PARC Computer Science Laboratory (CSL); Xerox’s purchase of Scientific Data Systems (SDS), and CSL’s MAXC, Alto, and EARS projects.
  3. More on the Alto system and what it influenced (including TCP/IP); the Future Day held by PARC for Xerox executives; the Dorado project.
  4. His departure from Xerox; the founding of the DEC Systems Research Center (SRC); the Firefly, Alpha Demonstration Unit, Autonet, AN2, and Petal projects; the founding of the DEC Paris Research Laboratory and its collaboration with SRC; the nearby DEC Western Research Laboratory (WRL) and its Titan project; a recap of the commercialization of Ethernet.
  5. Wes Clark, his TX-2 work, his LINC work, and his suggestion of decentralizing control for the ARPANET via a small computer (IMP) at every host; Taylor’s work in Vietnam at the end of his ARPA tenure; his approach to research management, including recruiting, interviewing, and performance appraisals.
  6. More on research management: informal celebrations, and the importance of a college intern program; reminiscences about people who worked at Xerox PARC CSL or DEC SRC or both.
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Notes from Lisp50

The Learning Lisp blog has an interesting series of postings on the recent Lisp50 conference:

  1. JonL Recalls How Sussman Revealed the Nature of Intelligence…
  2. Model-View-Controller Considered Harmful
  3. McCarthy Reaffirms the Importance of Having Access to the Abstract Syntax
  4. Fritz Kunze Enters the Lisp Mine Field
  5. Interlisp, PARC, and the Common Lisp Consolidation Wars
  6. The Future of Lisp
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Lisp’s 50th Birthday Celebration

A celebration of the 50th anniversary of Lisp is taking place in October at OOPSLA 2008. John McCarthy will give a talk about the early history of Lisp. Also Guy Steele and Richard Gabriel will repeat their 1992 HOPL-II talk about the Evolution of Lisp.

Faithful readers of this blog know that a good way to prepare for this event is to visit the History of Lisp web site at the Computer History Museum, which contains source code, manuals, and hyperlinks for many versions of Lisp starting with McCarthy’s Lisp 1.5.

Update 5 (7/10/2012): I updated the URLs for to use since the domain name seems to fallen into the hands of Japanese search engine optimizers, and I updated the hyperlink for JonL White because his ACM Author page now gives a 404 error.

Update 4: It was necessary to revise the schedule because of severe health issues preventing John McCarthy from attending in person. Pascal Costanza says McCarthy will be able to participate via live telephone interview.

Update 3: Now lists the Invited Speakers but notes “Title, abstracts, biographies and schedule will be announced here and at the Lisp50 blog in the coming days and weeks.”

Update 2: seems to be the URL for Lisp50@OOPSLA, but the Invited Speakers section still says “to be announced”.

Update 1: JonL White notes that the Association of Lisp Users is holding its “celebratory 50th Anniversary” conference at MIT in the spring of 2009, with Guy Steele as Program Chair and Dan Weinreb as General Chair; Dan sent out an “extremely unofficial pre-announcement” in February.

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VLISP documents; LISP Bulletin #2 and #3

Jérôme Chailloux recently told me about the wonderful ArtInfo-MusInfo web site, which contains a variety of documents produced by a group of “painters, musicians, psychologists, pedagogues, linguists, mathematicians, poets, architects and computer scientists gathered within the Computer Science Department of the University of Vincennes” during the period 1969-1980. Although there are many fascinating documents, I was especially interested in two collections:

  • VLISP manuals and papers, including dissertations by Patrick Greussay and Jérôme Chailloux. VLISP was the precursor of Le_Lisp, and served as a testbed for some of the implementation techniques of Le_Lisp.
  • LISP Bulletin #2 and #3, edited by Patrick Greussay & Joachim Laubsch. Danny Bobrow launched the LISP Bulletin with a first issue published in the September 1969 issue of SIGPLAN Notices, but no issues followed until Greussay and Laubsch took over.

I’ve updated the VLISP and LISP Bulletin sections of the CHM LISP web site with links to these documents.

Updated 11/26/2010: Updated URLs to reflect reorganization of

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ACM Classic Books Series

Last summer, ACM posted PDF versions of some books in its Classic Books Series, which resulted from a poll of ACM members initiated by David Patterson, who was then ACM President. The books are accessible to anyone who creates a free ACM Web Account.

The available books include:

Update: I had neglected to include the book by Aho and Ullman..

Update: The URL above for the ACM Classic Books Series was updated to

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The Revised MacLisp Manual goes online

MIT’s MacLisp played a key role in Lisp history, but its documentation often lagged the system as developers concentrated on adding features and improving performance. Around the time that Lisp machine development eclipsed PDP-10 MacLisp, this final MacLisp document was published:

  • Kent M. Pitman. The Revised MacLisp Manual. “Saturday Morning Edition”, M.I.T. Laboratory for Computer Science Technical Report MIT-LCS-TR-295, June 1, 1983.

This has been out of print for many years, but Kent just made available an updated, hypertext “Sunday Morning Edition”.

If you are interested in more MacLisp history, including earlier manuals, source code, and more, see the MacLisp area of the Lisp website at the Computer History Museum.

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BBC Radio observes Fortran’s 50th birthday

This week’s episode of BBC Radio’s Digital Planet show includes a short segment on the 50th anniversary of Fortran. The presenter, Gareth Mitchell, interviewed me last week and about 4 minutes of that interview are included.

If you’re interested, the show will be broadcast at various times December 18 and 19 (today and tomorrow); local schedules are available at this web page:

For one week only, starting today, an MP3 of the entire half-hour show can be downloaded from this web page:

The Fortran segment starts at about 19m38s into the show.

Update 2: With the permission of BBC Radio, I’ve added the audio of the Fortran segment to the Memoirs and user stories section of the CHM Fortran web site:

  • Gareth Mitchell, presenter. Fortran is 50. Digital Planet programme, BBC Radio World Service, December 18, 2007, 6′:40″. MP3 (7.6 megabytes)

    Mitchell interviews Paul McJones on the occasion of the 50th birthday of Fortran; additional commentary by Bill Thompson; produced by Helena Selby.

Update: A BBC reorganization removed the download link from the page above; in a comment below, Derek Mahar notes the episode download site is now and this download itself is

Posted in FORTRAN, Software history | 1 Comment

Computer History Museum videos coming to YouTube

The Computer History Museum has just launched a partnership with YouTube to provide a ComputerHistory “channel”. Right now it has 23 videos from various events and lectures at the museum; if you subscribe (via the orange button), you’ll be notified when more are uploaded. In the mean time, the museum maintains a calendar of past events with links to video, where available.

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C++ Historical Sources Archive

Observant audience members at Bjarne Stroustrup’s HOPL-III C++ talk this past weekend may have noticed on the last slide a mention of the C++ Historical Sources Archive at the Computer History Museum. This is a project Bjarne and I have been working on in the background for a year or two. Bjarne convinced the appropriate authorities at AT&T to approve releasing the Cfront source code, and then dug up listings, documentation, and/or machine-readable source for Cfront releases E, 2.0, and 3.0. Willem Wakker kindly supplied a copy of release 1.0. We have also tracked down some early libraries including libg++, COOL, LEDA, Array_Alg, STL, InterViews, ET++, and more. We would be very interested also in early applications written in C++ (especially pre-1990).

By the way, what was previously called the Software Collection Committee at the Computer History Museum has a new name (the Software Preservation Group), a new domain name ( and a new chairman (Al Kossow, the Museum’s Software Curator and the creator of

Posted in General, Repositories, Software history | 2 Comments

Remembering John Backus

As an undergraduate at the University of California at Berkeley in the late 1960s, I first learned of John Backus and his work on Fortran, BNF, and Algol. Around 1972 or 1973 I attended a talk John gave on “variable-free programming” at Berkeley. I was fascinated by programming languages (having worked on implementations of Snobol4, APL, and Lisp by that time), so I obtained and read a copy of his report “Reduction Languages and Variable-Free Programming”. In mid 1973 he mailed out a preprint of his POPL paper “Programming Language Semantics and Closed Applicative Languages“, whose margins I filled with notes.

In early 1974 I was looking for a job. My friend Jim Gray, who was then working at IBM Research in San Jose, introduced me to John, who was looking for someone to work with him on the design of his Red language and to implement an interpreter. We seemed to hit it off, and in March I accepted his employment offer. John mostly worked out of his home in San Franscisco. We discussed the possibility of locating my office in IBM’s Palo Alto Science Center, but I wound up joining the staff of IBM Research in San Jose, which was then located in the triangular Building 28 of the IBM Cottle Road Campus. John began driving down to San Jose once or twice a week in his diesel Mercedes. The only place in the area he could refuel was a truck stop in North San Jose. IBM colleagues told me I’d had an immediate positive impact: they now saw John much more than before.

For the next 15 months or so, I worked with John, discussing language features, writing various prototypes in Lisp and McG (an ISWIM-like language by W.H. Burge), reading papers on programming language semantics, and writing a report “A Church-Rosser Property of Closed Applicative Languages” that showed the operational semantics for Backus’s Red language was well-defined.

John was an inspiring person to work for and with. Despite his accomplishments (inventor of Fortran and BNF; Algol contributor; IBM Fellow) and the age difference (he started work at IBM the year after I was born), he treated me like he treated everyone: as a respected colleague. I had many suggestions for changing and extending Red, and John gave them all his complete attention. At that time, John was interested in pure functional programming, with no side-effects on storage or the external world. I advocated extending the language to allow writing complete interactive applications. John conceded the importance of this, and came up with a scheme in which one would write a function to express the complete transformation of an application on the global state. I struggled with John’s variable free style, and suggested we allow lambda variables when defining a new functional form (higher-order function), but he stuck to his guns. Gradually, I came to the conclusion that it was still too early to build a full implementation of Red, and I began spending more time talking to the System R team down the hall, who were designing one of the first relational database managers, and inventing the SQL query language and formalizing atomic transactions along the way.

John rarely wanted to talk about himself, but when asked he had interesting stories to tell. When he first joined IBM, he programmed the Selective Sequence Electronic Calculator (SSEC), a huge electromechanical machine whose programs and data were punched into a paper tape the width of regular 80-column punched cards, but many feet long. By gluing a data tape into a loop, it could be traversed multiple times. John recalled having to debug a program that would go through cycles of correct and incorrect behavior. Eventually they realized that the tape had a half-twist when it was glued into a loop, converting it into a one-sided Möbius strip.

John’s 25th service anniversary at IBM was in 1975. A recognition luncheon was planned in San Jose (at the IBM Country Club, or customer conference center), and John was asked who he’d like to attend. He named several of his current San Jose colleagues (I was honored to be included), as well as his old colleagues from the 1950s, including people from the Fortran project. The person arranging the event said, “But these people are in New York…”, and then came up with the travel expenses.

Cordial relations with John were not restricted to working hours. He and his wife Barbara invited my wife and me to dinner at their home, which turned out to be near the base of the Sutro Tower, with a beautiful view looking north from the Golden Gate bridge to the east bay. John said the only disadvantage of the location was RF interference to his stereo from the television transmitters. To combat this, he’d designed a Faraday cage by lining his equipment closet with aluminum foil. We invited John and Barbara back to our modest rental in San Jose, and they graciously accepted.

When I started at IBM, Nixon was still in office. John’s distaste for Nixon was no secret to his friends at the time. He learned he was one of seven people singled out to receive a “Presidential Prize for Innovation”, but then the plans were dropped. John later wrote that he “had been secretly planning to use the occasion to denounce Nixon and the Vietnam war. … I guess now my plan was not a gentlemanly scheme, but anyway I was relieved when the plan fell through.”

I stayed at IBM until November 1976, working on the System R recovery manager with Jim Gray, and then moved on to another job. A while later, I ran into John waiting in line for one of the West Coast Computer Faires — probably the first one, in 1977 in San Francisco. John told me he’d sent a deposit on an interesting computer called the MicroMind, from an outfit in Cambridge, MA, called ECD Corp. He was beginning to be skeptical that he would ever get a computer or his money back. I recently heard from Olin Sibert that ECD couldn’t build the machines cheaply enough, and returned all the deposits.

In 1977 John received the ACM Turing Award for “profound, influential, and lasting contributions to the design of practical high-level programming systems, notably through his work on Fortran, and for seminal publication of formal procedures for the specifications of programming languages.” John’s Turing Lecture, “Can Programming Be Liberated from the von Neumann Style? A Functional Style and Its Algebra of Programs” was devoted to his functional programming work, and had a large impact on the growth of a branch of academic computer science studying functional programming languages. John continued to work on functional programming until he retired in 1991.

I fell out of touch with John for many years. But in 2003, an effort I became involved with at the Computer History Museum to collect and preserve historic source code led me to get in touch with John regarding the original Fortran compiler. John was still living in the same house in San Francisco, and seemed pleased to hear from me. He didn’t have any source code, but did make several suggestions; eventually I found several versions of the IBM 704 FORTRAN II compiler source code.

Around this same time, I learned that John’s idea of an algebra of programs had had a big impact on my colleague Alex Stepanov (although Alex figured out how to apply this idea while extending the “von Neumann style” in an important way). At the time, Alex and I were organizing an internal technical conference for our employer, and we invited John to give a keynote speech. Just after he graciously accepted, his wife Barbara died; understandably he canceled the speech. John decided to move to Ashland, Oregon, to be near one of his daughters. Another colleague of mine, Dick Sweet, lives in Ashland and introduced John to a new circle of friends for what turned out to be his final years.

Although many people contributed to the early development of programming languages, John Backus deserves credit for creating the first successful higher-level programming language, Fortran. Fortran provided data types (integer and floating-point numbers), a powerful data structure (the array), expressions, statements, and abstraction mechanisms (functions and subroutines). The Fortran compiler generated optimized code taking advantage of the then brand new index registers and floating-point hardware of the IBM 704. Finally, the Fortran system provided a linking loader, a subroutine library, and I/O routines. The scientific and engineering users adopted it instantly, and it became the standard against which future programming language designs were compared.

Why was John’s contribution so important? He invented a language allowing one to express numeric algorithms in a way that was abstracted from irrelevant details of particular computers but that was efficiently implementable on a broad class of computers: from the vacuum tube IBM 704 of 1954 to the fastest supercomputer of 2007 and beyond. That idea, allowing the essential details of algorithms and data structures to be expressed in an abstract and yet efficient way, is at the heart of what programming language designers have been trying to accomplish for the last 50 years. Only a handful of them have made the kind of progress John Backus and his team did.

[Edited 10 May 2014: =>]

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Upgraded to WordPress 2.1

This blog is now running on WordPress 2.1. I’d like to thank the friendly staff at my ISP,, for moving my account to a new server with PHP 4.1.21.

Please let me (paul at mcjones dot org) know if you observe any problems with this blog. Thanks!

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