On 30/09/2021 01:06, Paul Koning wrote: > Either the diagnostic has a major bug, or you're running it on a machine it > doesn't support, or there is a setup to tell it the difference which you > missed. > > What you're seeing is the very first entry in the table "PDP-11 family > differences", appendix B of the PDP-11 architecture handbook. It is the > famous pattern that the assembler rejects with a Z (machine dependency alert) > error code. > > This particular pattern produces 6342 only on 11/23, 11/20, 11/35, 11/70, > J-11, and T-11. On all others, including the 11/05 and the PDP-11 emulation > in the VAX, it produces 6340 as you observed. > > paul >
Thanks, Paul. The MAINDEC-11-D0NB diagnostic is meant for the PDP-11/20 according to the listing though the same goes for many other diagnostics which are also applicable to the PDP-11/05. I guess this one is the exception. There is a newer version MAINDEC-11-D0NC but I can't find a listing for that one. Perhaps it has a switch register setting to handle the difference. I did wonder if this might be a model specific issue and I did various searches online but didn't find the right info. Thanks for the pointer. At least I know it's not a fault that needs debugging now. Regards, Matt
