Chatting with Ben Segal - Podcast Episode 5 - Chasing a Cheap IBM Computer

Jun 05, 2020

CERN Alumnus, David Garcia Quintas approached the Alumni Relations team some months ago with the idea of creating a podcast. Out of this idea is born the 'Chatting with Ben Segal' serial which you will find here on the CERN Alumni Network, in weekly installments.

Introducing Chatting with Ben Segal

 

Episode 5 - Chasing a Cheap IBM Computer

Ben: [00:00:00] I worked in Detroit with this British program. We would prepare the data for that program. We didn't have an IBM computer in our company, and you couldn't sort of send it out - there was no Internet. So I and one or two other guys would fly out to the cheapest IBM computer we could get hold of, which was in Philadelphia at an oil company. I can still smell the oil smell in the air.

Ben: [00:00:26] So we would arrive. Computer time is cheapest at night. We would arrive in the evening with our tapes and everything. And we'd go and eat some supper and we'd go out to the oil company and we'd go into the computer room. And they would be just finishing the shift and it'd be our computer for all night. So we'd get in, we could load our tapes, we'd do everything. And we'd have our cards, our punched cards and everything, and we'd leave with stacks of printout. But we had to babysit the computer: for instance when you ran a big program, the convergence, this was part of the thing - it was a big numerical mesh. You were solving what was called the diffusion equation. So it's like solving a heat equation, it's more or less the same equation. And so you start with a guess of the solution, and you'd iterate, and you'd check from time to time if the errors were getting smaller and the thing was converging, or not. If not, you'd have to change the input and start again.

David: [00:01:28] Yeah.

Ben: [00:01:28] So that was done hands-on, hands-on by... There was no screen. So from time to time you'd print a bit of results, you'd print some metric of what was going on. And to print, you'd have to stop the computer because the computer was single tasking. So if it was in compute mode, OK, it would remember. And then you'd stop it and you'd go into print mode, you'd print out what you had and so on. So you'd have the whole computer centre to yourself.

Previous Episodes
Episode 1 -Who Is Ben Segal
Episode 2 - How to Get Started
Episode 3 -Los Alamos
Episode 4 - Fun with Tapes


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