[Simh] More on VAX Emulation under Linux

[Carl Lowenstein]

On 6/16/06, Paul Hardy <pghardy at verizon.net> wrote:
>
>
> I could buy Exceed (at a non-trivial price) to run on my Windows laptop, but
> it would be even nicer if SIMH emulated one of the low-end the Vaxstation
> graphics cards (QVSS?). There was talk a few years ago of this being on the
> 'to do' list. Has it made any progress?
>
> I can't offer to do it myself (>10 years since I did any significant
> programming), but I'd happily help debug if someone else did.
>
> As a private project I'd like to get working and preserve in SIMH a major
> Vaxstation-based mapping and cartographic system that I was the architect
> of.

Speaking as someone who once was involved in programming QVSS to work
under RT11 in a Qbus 11/73, I would ask:  what should SIMH do as it
emulates the QVSS.   That is, where and how should the graphics bits
come out of the emulator.

A real QVSS is basically a piece of memory (RAM) that produces video
that is white where the bits are set and black where they are cleared.
 There is some hardware assist for scrolling the display, but not
much.  At one time, the least expensive way to buy more memory for
your Qbus system was to buy QVSS cards and ignore the video.

    carl
--
    carl lowenstein         marine physical lab     u.c. san diego