Hi.

I have two S3 Virge DX on a PC system, as well as a mono
card (a total of three monitors: two color (17" and 14"),
and other mono.
The resources shown by W98 are:

Virge #1
Memory intervals:
000A0000 - 000AFFFF
000B0000 - 00BFFFFF
E0000000 - E3FFFFFF
00C00000 - 00C7FFFF
06000000 - 0600FFFF
E0000000 - E3FFFFFF
I/O intervals:
03B0-03BB
03C0-03DF
IRQ11

Virge #2
Memory intervals:
06010000 - 0601FFFF
08000000 - 0BFFFFFF
IRQ11

W98 ignores the mono card, except for LPT1; as long as I use
it only for text there is no problem, in spite of Virge #1
showing it occupies 0B000-0B7FF. Also, although it shows
IRQ11 is used by both, in fact #INTA on both cards is unused
unless connecting something to its expansion connector.
It is surprising that Virge #2 is correctly programmed, even
not showing i/o ports.

Now, a simple experiment: open a DOS window on Virge #2 (so
on second monitor, so its pixels come from #2 card). Press
Alt+Enter to maximize it: it maximizes on first monitor!!!
(so its pixels now come from Vige #1). This confirms use of
range 0B800-0BFFF.

W98 supports fairly well several video cards. For example, a
window partly in both monitors seems to be maximized on the
monitor in which it has more pixels. However, it seems that
only first monitor has screen protector, although energy
savings turn of both monitors. RealAudio messes a bit with
two monitors (I posted something about this some time ago,
with no feedback).

************************************
Javier Vizcaino. Ability Electronics. [log in to unmask]
http://www.automodelismo.com http://ability53.hypermart.net
  Starting point:        (-1)^(-1) = -1
  Applying logarithms: (-1)*ln(-1) = ln(-1)
  Since ln(-1) <> 0, dividing:  -1 = 1     (ln(-1) is
complex, but exists)

----- Mensaje original -----
De: David Gillett <[log in to unmask]>
Para: <[log in to unmask]>
Enviado: martes 30 de marzo de 1999 0:10
Asunto: Re: [PCBUILD] Multiple video cards


> On 28 Mar 99, at 15:36, Max Timchenko wrote:
>
> > How exactly can 2 cards live in one system? they compete
for same
> > address space ($a000:0 and up), won't it cause
conflicts?
>
>   All VGA cards have to provide modes where the video RAM
can be mapped
> into the A000 segment (64K at a time) in order to be
accessible from
> DOS programs.  That is true.
>
>   However, constantly mapping and re-mapping this address
space is
> ugly, time-sonsuming, and pretty boring.  Most modern
video cards
> *also* map their entire RAM to space at a high
(non-swappable) virtual
> address, where protected-mode software can read and write
it directly;
> the drivers for the card know where this mapping is, or
how to find it.
>
>   So there's only a conflict at A000 if both cards are
trying to
> provide real-mode (DOS-compatible) access to video RAM.
As long as at
> least one of them has this mapping suppressed, there's no
conflict.
> [Actually, under NT and 9x, this mapping is generally done
by the OS,
> and used to connect to a "DOS window" on the screen,
instead of
> connecting directly to the video RAM.  So it's "extremely
normal" for a
> video card under Win32 not to map to A000 at all.
>
>   [There is a secondary issue that two VGA/SVGA cards
would normally
> want to use the same range of I/O port numbers and IRQ (if
any);
> solving that part of the problem seems like a natural
extension of PnP,
> which would I think be why this feature is only supported
by fairly
> recent cards.]
>
>
> David G

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