VAXen at home

On 17 Oct 2007 at 12:32, Patrick Finnegan wrote: All hardware. We didn't keep anything permanent on the development machines (tape and card was really the only permanent storage that I used). Cold deadstart/files reload from tape every time I came on the machine. We did keep some benchmark test data on 844 packs, but had backups for all of those. Typically, after the power would come up again, you'd see a couple of CE's staring at a scope hooked somewhere into the guts of a system with a dead display. A side bit of interest. PPU debugging on a 6000/Cyber 70/170 system was like driving in the dark with no lights--no blinkenlights or other indicators. If your driver was hung, you had to read the P- counter out bit-by-bit on a scope to figure out where that was. I wrote a PPU debugger that executed instructions one at a time very slowly in one PP under the supervision of a second. It didn't help much, but was fun to watch. The average CDC systems programmer, however, knew nothing about PP programming and wanted to keep it that way. Of those who did, even fewer knew anything about the firmware in the various controllers. Cheers, Chuck