On 2013-04-11 22:14, Mark Pizzolato - Info Comm wrote:
On Thursday, April 11, 2013 at 7:00 AM, Bob Supnik wrote:
1. Four Massbus channels on the PDP-11 (or VAX). This is straightforward.
The RH simulator already supports two, and the extensions from two to four
use the existing mechanisms:
- add the register blocks definitions to the header file
- define additional RHC, RHD devices with matching unit and register
definitions
- look for places where "2" is hardwired as the maximum number
- modify the autoconfiguration table for the additional device addresses
This is most of it, but additional devices and units must also be defined in
the pdp11_rp and pdp11_tu which then need to be connected to the new RHC and
RHD devices created above. Maybe a way to dynamically assign particular rp or
tu devices to a particular Massbus is also be necessary (someone might want 3
disk controllers and 1 tape, while others might want 3 tape and 1 disk
controller, etc.). If mixed configurations are possible something needs to
validate that there are no Massbus conflicts.
Isn't there already? I mean you should not be able to attach two
different disk drives with the same unit number. And that is the only
kind of conflict you can have.
From an RSX point of view, even having an RM and an RP disk on the same
Massbus is considered a mixed Massbus. Like I said before. RM and RP are
not the same from the host point of view, and should most likely not be
considered the same from simh point of view either. But that is another
issue.
Conflicts, as such, can only be about the unit number.
2. While real documentation for the RS03 and RS04 is lacking, they are
described in adequate detail in the early PDP-11 IO handbooks, which are on
BitSavers. This would probably suffice to run the operating systems, but not
diagnostics. There is also some information on issues in the RS03 and RS04 in
the Massbus standard.
Good to know.
This, along with the driver sources which Johnny Billquist mentioned are
probably sufficient for someone to implement things.
Yeah. I don't expect that it would be very difficult if someone wanted
to add more Massbus devices.
Johnny
_______________________________________________
Simh mailing list
[email protected]
http://mailman.trailing-edge.com/mailman/listinfo/simh
