X11 expertise on ancient HW sought... (4-plane visual (overlay) via X-server on MS-WIndows)

[Tomasz Rola]

On Thu, Jun 04, 2015 at 08:24:31PM +0200, IMAP List Administration wrote:
> [also posted to comp.graphics.x today]
> 
> Hello Folks,
> 
> I'm trying to get an application that currently uses a local display
> on an ancient DEC Alpha workstation with a (for the time)
> mid-to-high-end graphics controller (ZLX-E2) to instead use an
> X-server running under MS-Windows.
> 
> The application is complaining that it cannot find a "4/5-bit
> visual". It almost certainly wants to use this visual for an
> overlay, as the application displays moving objects superimposed on
> a map.
> 
[...]
> I have tested VcXsrv, Reflection-X, Exceed (with 3D option), X-Win32
> and even the ancient DEC Pathworks X-server eXcursion with no
> success. I'm working on getting an evaluation copy of PTC's MKSTools
> X/Server. Of the X-servers I've tested, Exceed seems to offer the
> most configuration parameters.
> 
> I'm not even sure the Quadro 400 can handle 4bpp "visuals", or
> whatever MS-Windows calls them. In fact, I wonder if any modern
> hardware offers 4bpp capability. On my Linux box with a GeForce GT
> 430 I don't have any 4-plane visuals, and xprop doesn't mention any
> overlays either.

Pardon my ignorance, I'm definitely not an expert and after sending
this msg I am going to hide and pretend to be dead. However, I cannot
see if you tried running your app on Linux-based X server. This might
be easy to do and does not even require installing Linux. When I want
to test some new hardware, I usually download GRML onto pendrive and
boot from it. It's small, really, like half of CD-ROM. And it has
relatively new X-server, plus few other things like compiler and Open
Office, but in this case it doesn't matter.

https://grml.org/

In case you go this way, it may make sense to read some manpages and
experiment with options to server - different color depths, screen
size (a.k.a. resolution). Perhaps there are some options to the client
(DEC app) too, and maybe there is a match.

BTW, is the problem related to just one app your customer wants? Can
you run xterm from your DEC and display it on new X-server?

I'm not sure what GPU has got to do with 4 bits per pixel stuff. I
have always thought the problem with bpp is only when graphics chip
doesn't have enough memory to handle, say, 1024x768 pixels, each
containing 4 bits (16 colors mode), i.e. it has less than 384kB of
RAM. And in such case, every app could have its own colormap, which
caused display to blink in a psychodelic way. The last time I even
bothered was probably when I added 1MB of video memory to empty socket
on S3 video card, which allowed me to run X in 800x600 24bpp
mode... about 17 years ago. So I think it would be a bit strange to
have such problem today.

Anyway, I'm definitely not an expert. Consider my questions as
controls or noise, I have no idea what they are. Now I will run and
duck.

-- 
Regards,
Tomasz Rola

--
** A C programmer asked whether computer had Buddha's nature.      **
** As the answer, master did "rm -rif" on the programmer's home    **
** directory. And then the C programmer became enlightened...      **
**                                                                 **
** Tomasz Rola          mailto:tomasz_rola at bigfoot.com             **