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.
Chatting with Ben Segal
Episode 4 - Fun with Tapes!
How to run your IBM-specific program on another compatible computer: fly 8000 km (5000 miles) with a magnetic tape under your arm. And then, what to do when your program doesn’t fit in memory all at once.*
David: [00:00:00] It may be interesting for someone listening to realize that carrying a program with you physically is not insane, given that this was in the '60s and that ...
Ben: [00:00:10] There's no other way because it was a program that only ran on IBM machines, OK, so it wasn't portable, it was written in FORTRAN.
David: [00:00:17] OK.
Ben: [00:00:18] But it was built for running on IBM. By the way, what's interesting: IBM computers at that time couldn't fit in a big program or all of a big program into memory.
David: [00:00:31] Right.
Ben: [00:00:31] So they used mag tapes - what was called chain tapes. So you would actually load the first part of the program, maybe the part that would read the data, you'd load that first and then you'd read your data in. And then the operator would have to take the tape off and put another tape on. It would read maybe the main program in. And I certainly remember when the program had finished running, and it was ready to print, you would have to change the tape to the printing the output, you know, things like that. So the resources were so restricted in memory and power.
*** ERRATUM: Chain tapes had a set of files on them so there was no need to physically change the tapes between program sections (BS) ***