Crazy Eddie's Used ComputersMar 8
I went down to @icm to work on Miss Piggy, their PDP-11/70 system. Any instruction that touched memory would wedge the processor (though front panel accesses worked OK). Brought along my KM11 diagnostic set to help diagnose the issue and traced it down to a faulty microcode ROM (one of several early bipolar 256x4bit PROMs in the system). We had a spare ROM board so we swapped that in; chip-level diagnosis will happen at some later date. The system boots 7th ed. UNIX once again!
Show threadKarl Auerbach

@fvzappa @icm I've got the console - and only the console - from one of my old PDP 11/70s. I used to have the boot address in the switches but somebody messed 'em up.

My fingers sort of vaguely remember the switch settings to boot Unix (we mostly used Interactive's IS/1), but they have forgotten the details and I'd like to put the switches back to what they ought to have been.

Mar 8 at 3:54pmWeb
Show threadICMMar 9
@karlauerbach @fvzappa 165020