One thing I’ve done is dump the ROMs in my two AV300D. They’re identical except for the last 4 bytes, which I suspect is where their host/Ethernet ID comes from.
Unfortunately while the ROM is a JEDEC 1Mbit part, my dump doesn’t look coherent, in that there’s no simple ASCII text like appears at boot, and the contents at 0 are not proper 88100 instructions. I expect Data General didn’t use D[7-0] on the ROM as D[7-0] — and may not have used A[16-0] as A[16-0] either. And since my systems have bum power supplies, I can’t boot them and dump the ROMs that way. Anyone have a running AV300 or AV400 system from which you could dump the ROM via SCM (the boot monitor)? Then I could compare it with my dump and figure out how it’s wired up. If anyone likes puzzles, here are the last 8 bytes of each system’s ROM: $ tail -n 1 AV300-10794-01-1AFB.hex 0001fff0: ffff ffff ffff ffff 7184 f4a2 04fb 67fe $ tail -n 1 AV300-10794-01-3163.hex 0001fff0: ffff ffff ffff ffff 7184 f4a2 9cfa f7fc The ROMs were labeled 1AFB and 3163 respectively. If anyone can see a coherent mapping in that, I’d be quite happy. :) — Chris
