[ams6110]

Conversely, back in the days if you had any kind of a significant IBM mainframe installation you had an IBM technician if not a team of them on an on-site contract to keep the thing running. The idea of an unattended data center, filled with computers that can run reliably for years untouched, was unthinkable then.

[jacquesm]

When I was still working with mainframes we used the IBM diagnostics on a Sperry machine (it could emulate the IBM instruction set), they were so much better than the Sperry ones that hardware faults would be isolated much quicker.

One of the best hackers I ever worked with (a guy called Paul Poelenije, unfortunately deceased) had figured out how to load the microcode store and to pull this trick, I'm pretty sure that both IBM and Sperry would have been horrified at it in equal measures. For an encore, he wrote a completely new filesystem in assembler, and used it in production for the bank we both worked for. How he got away with that I'll never know but somehow he managed to get the blessing for his pet projects from the manager of the systems programming division to who I'm going to be eternally indebted because he had a big say in me coming to work for the IT department instead of the mailroom.

Those Sperry's were massive machines, the two mainframes (primary and backup, or production and test depending on what we were up to) + peripherals took up all of one floor of a very large office building and there were always at least several people on duty to keep them running. This was mid 1980's and punch cards were still being used with some regularity.

[reaperducer]

+1 for even knowing the word "Sperry."

I named my dog Sperry simply because nobody in my company had ever heard of it, and I didn't want the name to die.