It’s APL’s Birthday! Or is it?

Last year we discovered that the first APL workspace was saved November 27, 1966 at 18.53.59. (GMT); the excitement of this momentous event pulling the guys away from home and the American Thanksgiving holiday.  Today we know that this evidence isn’t 100% the truth…  it’s more like 99.7% truth…  According to an eyewitness account from my dad history has been slightly amended… if only by a few seconds!

Should today be APL’s official birthday?

It just so happens that 2012 is the 50th anniversary of the publication of that one little book, “A Programming Language“. THE one little book, that Harvard deemed too small to launch its author, Kenneth E. Iverson into a tenure track position.  Harvard sent Ken packing! It wasn’t until much later that Ken’s work and this one little book was recognized by the world,  winning the Turing Award which is recognized as the “highest distinction in Computer science” and the “Nobel Prize of computing“.

The moral of this story?

Do it right and do it well.  Happy Birthday APL!


Many thanks to Rick Procter who reminded me about the significance of 2012 earlier this fall.



15 Responses to “It’s APL’s Birthday! Or is it?”

  • Wow! I was only in 2nd year at U of W in 1966. I didn’t start using APL ’til 1970. And I thought I was one of the early users!

  • Took the liberty of reposting this at Vector.

  • Did you know that at least three Turing Award winners were denied tenure at their universities? Who they are. I am fortunate to be personally acquainted with two of them.

  • aprogramminglanguage aprogramminglanguage

    Roger! I LOVE that both Iverson and Dijkstra are on your who they are list!

    Thanks for sharing!

  • In the fall of 1970 I was introduced to Iverson Notation, to express algorithms. I was impressed by its brevity and unambiguity. For the first and only time, I enjoyed homework.

    In the spring of 1971, I took a “survey” class about programming languages – a different one each week. I was standing outside a classroom and overheard two classmates:
    “what’s the language this week?”
    “what’s that?”
    “it’s Iverson Notation on a 2741 typewriter terminal”

    … Instant love. Not only my favourite language, but no more punch cards. Little did I realize then that it would set my life’s career path.

  • aprogramminglanguage aprogramminglanguage

    Thanks for sharing, Brian.

    There are many of us out there who feel completely awed by the happy accidents that lead us to APL. I also feel lucky, especially as a woman in tech, to have had such an awesome programming career with all the lifestyle benefits that come with this place in society!

    And imagine my surprise when I learned how privileged I have been to be immersed in a community with such intelligent, thoughtful and careful people. I used to believe all people in the world are this smart! OH!

  • I never knew that Ken was denied tenure at Harvard.
    My first exposure to Iverson Notation was a lecture by KEI at Stanford Research Institute in 1961 or 62. Several of us from the Stanford Comp Center attended. I did purchase a copy of the book shortly after it was published. Those arrows down the side for branching seemed a barrier to implementation.
    Some features such as +/X seemed to present an opportunity for compiler code generation. An efficient looping form could be used which is not always the case with a FOR statement.

  • Catherine says:
    > Roger! I LOVE that both Iverson and Dijkstra are on your who they are list!

    Ironic, isn’t it? As you know, Dijkstra was dead set against APL. (See for example this 1978 article by Perlis.) I’ve looked at some EWDs briefly, and as I was reading one I said to myself, “APL should be a natural for this guy!” Dijkstra was interested in writing provably correct programs, and APL programs are easier to prove correct than programs in other languages.

  • aprogramminglanguage aprogramminglanguage

    RDM – There is a strong contingent out there very eager to hear more of your side of the story!

    Mr Hui – The funny thing is, every time I say anything critical about Dijkstra I get trouble from my dad!

  • Catherine – nice post and thanks for the reminder. Yes, definitely Happy Birthday.

  • aprogramminglanguage aprogramminglanguage

    Thanks for posting A Programming Language online for us all to see, Lee.


  • I thought I was one of the early users, I first used APL in 1985, on an IBM 360 mainframe computer.

    The IBM guys sent a deputation round to our research labs at Berkeley and to persuade us of the value of APL and i admit, it did prove handy for our time series stats.

    IBM never mentioned anyone else inventing APL.

  • aprogramminglanguage aprogramminglanguage

    Thank you for your note, Ray.

    Kurt W. Beyer has a really interesting analysis of IBMs position and literature concerning inventions in general and in particular with respect to Howard Aiken in his biography of Grace Hopper. (Aiken was Dr. Iverson’s advisor at Harvard). It was Beyer’s analysis which inspired my thoughts about what you are saying. I believe there are at least two forces pulling on APL with respect to credit and profit; those of a protective proprietary patent culture (beginning with IBM) and those values which evolved from mathematics which concern sharing scientific information for the advancement of humanity. APL certainly straddles both world views which is one of the reasons it makes such an interesting subject for a documentary.

    I have never heard that IBM denies Dr Iverson as the inventor of APL but on the other hand, it would be uncharacteristic of that organization to give credit to any individual for a particular invention (thought they do have their “Fellows”).

  • Talk about starting at the top. Working for and with Ken Iverson was my first job out of college. Roger and I were introduced to Iverson Notation at the same SRI chalk talk. I didn’t do anything with it at the time, but a while later an IBM maverick technical guy and rhyming philosopher, Michael Montalbano, started hanging around Stanford’s brand-new computer science department. He was writing linear programming algorithms in the Notation, then hand-translating them into Fortran for his business-school students. He gave some informal lectures on the Notation; Phil Abrams and I attended enthusiastically.

    IBM announced the IBM System/360 on April 7, 1964. Shortly after, Mike handed me a new IBM Systems Journal that had articles by the System/360 architects — and holy cow, one by Ken Iverson, Adin Falkoff, and Ed Sussenguth that precisely defined the whole 360 line in 18 pages of Notation, plus commentary: “A Formal Description of System/360.”

    Phil and I devoured it. Once past the steepest part of the learning curve, we gave a series of seminars to other students. I found a few typos, which I mailed to Ken.

    Then Ken came to visit, touring several institutions to talk about the Formal Description and his notation. I listened, argued once or twice, and handed over my latest errata. Ken thanked me, and said “Larry, these are pretty minor. Why don’t you find something seriously wrong?”

    Nothing could have fired me up like that challenge. I scoured the article. Late at night I sat in bed, with the fold-out pages resting over my recent bride’s nose (a nuisance) and eyes (appreciated). I got lucky. The Memory Access program had a race condition between requests from the Processor and Channel programs.

    Next day at lunch I showed Ken what I’d found. Mid-afternoon
    Mike came by my office. “Larry, Ken’s taking the Lord’s name in vain. He came back from lunch saying ‘That sonofabitch Breed! Why didn’t we talk to him before we published this god-damned thing?'” And I knew that I had to go to work for him.

  • aprogramminglanguage aprogramminglanguage

    Wow. APL’s birthday sure stimulates some interesting and lively discussion! Incidentally, this is also the the time of year we get attention on the world-wide-stage. For these reasons, I have decided to set November 27, 2016 as the release date target for the documentary. The 50th anniversary of that first )save. (And four more years might seem like a lot of time, but it actually puts us at the production cycle for the AVERAGE documentary according to my very unscientific sleuthing)

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