Letter: Memories of Ken Iverson and APL
Vector 22:4, page 7
| From: Paul Barnetson (paul@barnetson.fsnet.co.uk) | 30 September 2006 |
It was with great interest, and with many happy memories, that I read the Vol. 22, No 3 edition of Vector, with its theme of “Remembering Kenneth Iverson”.
When I was young, and before I reached the “age of discretion”, I used to irritate my friends and family no end by continually asking them what they meant by the words they used, and pinning them down to get precise definitions. It was to nobody’s particular surprise that mathematics was my favourite subject at school and university, before I joined IBM to work with computers. And back in 1963, that was a burgeoning and very new field!
In 1968 I was sent on assignment to the USA for a couple of years, and while I was there I was introduced to APL, “the language that forces the computer to think in the way that you do, rather than forcing you to think in the way the computer does, like other languages”, as it was described to me.
I fell in love with it then, and on my return to the UK, set out to evangelise about it within IBM-UK. During the 70s I was IBM-UK’s “APL-man”, and some of your older readers might remember me in this job.
During this time Ken wore a beard, many of his US colleagues also did, the marketeer for APL in IBM-UK had one too, and as the technical man I also wore one. With vivid ginger hair at the time, I was the man with “the red one”, and a hirsute appendage was expected of all male APL enthusiasts!
One of my contributions during this time was being secretary to the APL Standards Group, ably led at that time by Dave Ziemann; I think he eventually moved over to a language called Smalltalk. We used to spend hours arguing over whether a particular feature involved standardising the interpreter or the language – not an easy thing to decide – not to mention discussing whether we were standardising what had been done, or whether we were trying to lay down rules for the future.
In the early days, when APL was still only available on 2741 terminals, I would travel to various exhibitions and conferences to organise demonstrations of this marvellous new language. I was always accompanied by my carefully guarded box of APL golf -ball typewriter heads. This box was immediately labelled “Paul’s Balls”, much to the amusement of my mainly female demonstrators – I really don’t know why!
At another APL conference I was chairing a presentation (by Bob Bernecky I think), and a marketing company had given everybody a name badge with a number on. Prizes were being offered for delegates who could find somebody whose badge had the same number as their own. So I defined SET as the collection of all the badge numbers in the auditorium, and I invited everybody to re-organise themselves according to
This way, they would find themselves sitting next to the person with the same number as themselves! If N was the number on my badge (I forget what it was now), I then wrote up
to find there was a match in the auditorium! We later collected our prize together.
I was lucky enough to meet Ken during this period, along with many of the contributors to this particular Vector. Adin Falkoff, Jim Brown, Gitte Christensen, Per Gjerlv, John Scholes, Morten Kromberg, Gerard Langlet, are all people who helped me along the APL way, not that there is any reason why they should remember me. I still correspond with Norman Thomson – he has tried to convert me to J! But you can’t teach an old dog new tricks.
Now I have retired, I still use APL. One application is writing packages for charities; an example is The Charlton Chase, an overnight orienteering event for young people on the South Downs in the middle of winter. My package enables us to calculate when we could expect the teams at their next checkpoint, and so warn us if they are overdue. It also enables the young people to have the final results immediately the last team returns. I wrote an article on this package for Vector, a long time ago now.
As an enthusiast of recreational mathematics all my life, I have also used APL in innumerable problems concerning magic squares, prime numbers, and the like. I find these in New Scientist (Adrian – I also solved Enigma 1368, and in exactly the same way that you did!), and thanks to APL my name has appeared on three occasions as the lucky winner. I have also had similar problems published in Computer Weekly, which carries a “Puzzler”each week.
My only problem is finding a cheap single-user modern APL system; the ones on the market are expensive multi-user systems. Would you believe I’m still using a 1980s version of PC. APL, which somehow came home with me when I left IBM!
My regards to all my old APL friends and colleagues, and – like them – I can truthfully say that APL changed my life.
We’ll miss you, Ken – you changed the world, and not many people do that.
Thank you for the chance to write this letter.
Paul Barnetson
22, Ferndale Rd
Chichester
W. Sussex PO19 6QJ