🚀 go-pugleaf

john.navas@uttsbbs.uucp (John Navas)  writes:

>With all due respect, I'm afraid I don't buy that argument.  The
>shadow memory required for a standard VGA 640x480x16 graphics screen
>is only 150Kb; for SVGA 800x600x16 it's only 235Kb.  True, it's easier
>to shadow the entire video buffer, but it's not strictly necessary.
>Even so, 256Kb, which is not a very big deal, is adequate to
>virtualize standard VGA 640x480x16 graphics; i.e., 4 virtualized VGA
>graphics applications would require a total of only 1Mb of shadow
>memory.  ( yawn :)

>In fact, OS/2 allocates a full shadow buffer of up to 1Mb for every
>full-screen DOS application, so that it can save the display when that
>application is switched to the background.  So the amount of shadow
>memory is not really an important factor.

Agreed.

>Again, with all due respect I don't buy that argument.  DESQview
>virtualizes standard VGA 640x480x16 "bit plane" graphics in a window
>or in the background with acceptable performance.  If DESQview can do
>it, there's no reason OS/2 shouldn't be able to do at least as well.
>Although 640x480x16 would certainly be enough to satisfy me,
>supporting 800x600x16 wouldn't be all that much harder.

640x480x16 should not be too difficult, but I would say that 800x600x16
would be quite difficult each display card type does this in a different
way.  There is no single standard for 800x600x16.  The highest resolution
that is a VGA standard is 640x480x16.  They should however be able to
create some sort of mechanism to simulate a SVGA mode, but it would
require a lot more work.

James Weinkam