[Simh] Questions regarding future simulator development

[Mark Pizzolato - Info Comm]

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.

> 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.

- Mark