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From: mouse@lightning.mcrcim.mcgill.EDU (der Mouse)
Subject: Re: Multiple screens on a color SUN
Message-ID: <9104092307.AA04240@lightning.McRCIM.McGill.EDU>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Date: 9 Apr 91 23:07:39 GMT
Lines: 29

> A while ago someone asked how to use multiple screen on color Suns.

> As far as I know, only the 'cgfour' graphic card supports this
> option.  It has 9 bits per pixel - 8 per color and one for B/W.

Ten, actually; the tenth specifies, for each pixel, whether color or
B/W is to be displayed.  X keeps this "enable plane" full of either 0s
or 1s, but the hardware actually supports displaying the 8-bit plane in
some areas of the screen and the other plane in others.  (And while
we're picking nits, it really isn't B/W.  In X terms it is one-bit
PseudoColor, though X, or at least MIT X, doesn't know how to take
advantage of that.)

> In my previous job I had a Sun-4/110 which also has two screens, like
> the 3/80.

> It was very simple:
> - for b/w   apps, use DISPLAY=<whatever>:0.0
> - for color apps, use DISPLAY=<whatever>:0.1

That was true under R3; in R4, the color screen is screen 0, with the
monochrome screen as screen 1.  (Probably because color performance was
improved enough that running on the color screen was usable instead of
excruciatingly slow.)

					der Mouse

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