Source control in the 1980s using a pink dinosaur, part of Paul Fellows’ tales of Acornsoft, Arthur and RISC OS:

We had 7 or 8 guys trying to write an operating system to go into a ROM, so you’ve got to get it right, and they’re all doing different bits of it and some of these share system files. No CVS, no source control, no Sourcesafe, none of that. The solution was the main system header file with all the constants, SWI numbers and addresses of everything lived in. You could edit that if you had the pink dinosaur on your desk. If you did not have the pink dinosaur on your desk you could not edit it. If you edited it without the pink dinosaur, my Australian friend, Brian Cockburn, would come round and see you.