[Simh] Emulated Graphics card?

[Holger Veit]

Am 11.05.2011 09:53, schrieb DELAFOSSE, Gilbert:
>   Markus
>
> You already have a pseudo VAXstation with "off the shelf" tools
> You only need
> - Simh
> - an X11 emulator (Xming or Cygwin in the Windows world)
> That's it. You can even have Simh AND X11 running on the same machine
> With a brand new PC, you will outperform any VAXstation (Except perhaps the VAXstation 8000)
> Runnig a VAXstation on a laptop is great
Yes and no.

Infact, you can run a VAX simh and install the X client software in VMS 
and redirect the client to almost any
X server (including a local Xming). This is comparable to having a 
physical VAX with attached X terminals.
Emulating the hardware the native VMS X server expects is here not 
useful, as you correctly remarked; it
unnecessarily drains performance from the emulator.

But this will solve the problem for any platform which already talks the 
lingua franca X11. Imagine any other
workstation of that time, for instance an Apollo Domain that had its own 
windowing system incompatible to X11.
Either you run it in text mode or through serial terminals, or you are 
forced to emulate some sort or more or
less intelligent bitmap video device.

This brings up the matter of GUI again. I am unsure about an API for 
such a bitmap device to become useful,
particularly when it comes to devices that are outsourced to an external 
networked process. The streaming
model used with ordinary text terminals (ESC sequences) is not suitable 
here; very fast you end up with a real
protocol which we already have: the X protocol. But this then makes 
implementation very expensive even when
you use higher level libraries like Motif, Qt, or SDL (in contrast to Xlib).

-- 

Holger


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