On 1/11/19 2:32 PM, Noel Chiappa via cctalk wrote: > > From: Allison Parent > > > Most Probable cause is interrupt grant is broken. > > The only -11 that complains if the grant chain is broken that I know of is > the /34 (maybe the /04 too). I certainly have a QBUS chassis right next to my > workstation here that i) has a bunch of empty slots, and ii) works fine, as > long as there are no empty slots between the CPU and the devices. > > Also, IIRC he said it works with 3 cards plugged in, but not 4; how can > plugging a card _in_ cause grant problems? > > > For most microspheres backplanes the first three slots are different > > than remaining. > > That might be worth checking into. I'm not familiar with the second box > he's using, so can't help there.
MicroPDP box has first three slots A-B-C-D to support PMI memory and the rest are serpentine A-B. Even giving a bus grant problem, I can't see that causing a CSR error. I will probably have to dig out another box this weekend just to be sure there isn't a problem with the backplane. bill
