[Simh] UDA/KDA/KRQ emulation

[Bob Armstrong]

  It looks like _any_ MSCP emulation in simh on a UNIBUS machine reports the
controller type as a UDA50, and any QBUS simulation reports the controller
as a RQDX3.  This is a rather simple approach that leads to all kinds of
funky and incorrect situations, especially on the QBUS.   For example, if
you attach an RA drive to a QBUS -11 and boot RSTS, then RSTS will tell you
that the controller is a RQDX3 with, say, an RA81 drive.   Clearly
impossible.  Likewise if you attempt to use a RRD40 on a PDP-11 it'll think
the controller is a RQDX3 - again, impossible.  I'm more than a little
surprised that RSTS doesn't crash, given how fussy RSTS is about the
hardware, but it doesn't seem to care.

 

  In any case it bugged me to see all these bogus hardware configurations,
so I've hacked up (er, "enhanced") the "set rq" command in simh so you can
now say

 

                set rq uda50

                set rq kda50

                set rq rqdx3

                set rq krq50

 

There's no sanity checking so it's still possible to create impossible
configurations, but at least now you can actually create _possible_
configurations too.

 

  Even this is still a pretty simply minded approach, since other things
(e.g. hardware revision level, firmware version, etc) should also change
when you change the controller type, but at least now when the emulated OS
shows the hardware configuration you get rational results.

 

  Is this worth adding to the simh code base?

 

Bob Armstrong

 

 

   

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