On Sat, Feb 19, 2022 at 4:40 PM Fritz Mueller via cctalk <cctalk@classiccmp.org> wrote: > > On Feb 19, 2022, at 12:11 PM, Fritz Mueller <fri...@fritzm.org> wrote: > A few additional details, in case it is helpful: > > IIRC, the 11/34 doesn’t have SACK timeout implemented in the CPU cards (the > /34A did add this, however.) So without an M9302 on the far end of the bus, > the CPU could hang in a situation with an unacknowledged grant (which I think > would be somewhat rare, but possible). I believe it is possible to boot an > 11/34 at least as far as a ROM boot monitor with a non-SACK (M930 or such) > terminator on the far side.
Thank you for bringing this up - I have a stack of KD11-E and KD11-EA board sets (and MOS memory and all the other things). I've been trying to get them to work in a BA11-L that started off life as a PDP-11/04 and I've swapped the DD11-DK for a DD11-P backplane but I wasn't having any luck getting things to run. I did find a bad 7402 in the limited function front panel but that was the only fault I found (so far). I've checked the grant chain but what I haven't done is ensure I have the right combo of terminators and CPU cards. I'm used to configuring machines, but I honestly forget if the experiences I had in the 80s were 11/34 or 11/34A. This gives me something to go back and check. I was about ready to start hacking on an M9302 to sniff out the SACK logic. Now I'll go back and check the docs and make sure I'm putting together a set of cards that's going to want to play nice with each other. I have plenty of dual-height grant cards. I'm definitely _not_ having issues with NPR. Thanks! -ethan
