Tuesday, 27 October 2015

Back to the Future

There is a beach in Argyll which is the first I ever knew. I knew it as a toddler, babbling with incoherent thoughts, and I revisited it every year until I bade it a conscious farewell when was eighteen. Each of those years was, if not a flash, then a smudge of light in space and time. Revisiting it again now is as close as I may come to time travel.

Of course the beach is spinning at five hundred miles per hour relative to the Earth's core, orbiting the sun at sixty-seven thousand, orbiting the centre of the galaxy at four hundred and ninety thousand and hurtling outwards towards the Great Attractor at over two million miles per hour, so it cannot be said to be static. But to all appearances the same smooth, familiar boulders emerge from the same sands, washed by the same sea and surrounded by bladderwrack and thrift from the same DNA. They have not aged as I have aged, and relatively they have remained motionless as I have travelled in time and space, and then returned.

It is an odd feeling standing there, as those distant cones of light from the past still spread everlastingly outwards, carrying images of a growing child playing in the sand, decaying fragments of home movies, while I stand simultaneously in the present and the past like Marty McFly, haunted by the echoes of voices and laughter and the Zeitgeist of those onion-layered other times.

Wednesday, 21 October 2015

Investing for the Future

It is traditional, when a child is born, to lay down a case or two of good claret for their wedding. I couldn't afford that, so thought I'd do better by anticipating the market. Amongst other inspired and prescient investments I reasoned that, with women's rights and increasing political correctness, the tacky sort of risque pottery one saw in seaside shops - boob-shaped jugs and mugs with wobbling breasts, you know the sort of thing - would become a thing of the past. Unfortunately they haven't. I mention this to explain, when I one day shuffle off this mortal coil, the box of pornographic pottery my heirs will find in the attic.

Friday, 16 October 2015

Alan Turing (and how he might have helped with my homework)

I am re-reading Andrew Hodges' book 'Alan Turing: The Enigma'.

In 1974 I was working with another planning student, developing a practical trial of a computer model called the Decision Optimising Technique (DOT). We were mentored by the model's creator, a PhD post-graduate student named Stan Openshaw. According to Wikipedia, he, like Turing, was a believer in human-competitive machine intelligence (and I gather became something of a world-class authority on the subject). There had been considerable work on the modelling of systems behaviour but, beyond critical path and cost benefit analysis, decision-making had fallen behind. Our work aimed to take forward the AIDA model (Analysis of Interconnected Decision Areas), which had a number of flaws - in particular its incremental nature and reliance on over-arching value judgements.

The Newcastle computer occupied an entire basement two floors underground. It featured ranks of steel cabinets with memory provided by spinning magnetic drums. Access was via remote keyboard terminals, in our case using stacks of punched cards which were fed into the machine on batch at night.

Even though this leviathan IBM computer could be linked with its siblings at Edinburgh and Imperial College in London to increase processing capacity, we found that all but the smallest real-world problems were too complex for the runs to be completed. While my colleague wrestled with the serious maths and machine coding, I found more and more of my energy being devoted to devising ways of limiting and reformatting problems to reduce the scale of calculation the computer was being required to address. Initial attempts to use 'IF' statements or positively/negatively link decisions by use of 'bars' (as in the AIDA model) were not enough, and amongst other tricks we hit on the idea of assigning token numerical values to individual decisions, allowing us to use constraint equations as a substitute.

It is fascinating to learn that Turing was struggling with exactly the same problems when he was trying to break the Enigma code on his 'Colossus' at Bletchley Park, and after the war when he was developing his 'Automatic Computing Engine' (ACE...arguably the first electronically-stored-program computer). Like us, much of his time was spent devising ways to reduce the iterations of the machine, and he too realised by giving instructions bogus numerical values he could use equations as a substitute for 'IF' statements. I suppose similar problems spawn similar solutions, but I wish we had known about his work then.

It is odd to realise that we were working only twenty years or so later; that the computer we were using, with its punched cards and steel racks, was ACE's direct successor; and that the bog standard PC I am writing this on would probably be capable of running DOT in minutes, not hours or days.