A lot of DEC stuff went to universities, where there
was a lot of
hands-on in the guts (how many 360's were moded by students and
faculty?), departmental hand-me-down leading to surplus.
IBM stuff tends to be VERY hard to mod because of the design philosophy -
everything is done very properly and checked. Attempting a mod will result
in modifying the circuit that checks the modded circuit, then the circuit
that checks the checker...
IBM docs are amongst the best out there, once the system is
understood. Usually these docs were pretty much available in the computer
room, so a bribe (beer works at a university) would get the Big Blue
Binders.
William Donzelli
aw288 at
osfn.org