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Two graphics cards at the same time in an XT

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boggit

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I'm still very new to all this, so I apologize if this is a stupid question, but...

1. ...would it be possible for me to attach both a CGA card and a VGA card to my motherboard at the same time?

2. And if so, is there a convenient software/bios* way to switch which one I'm using, so that I won't have to open my case and physically fiddle with the switches on the motherboard?

*I've ordered a XT-IDE CF lite card, so possibly through XUB?
 
mdog69 said:
Because installing a MDA/HGC plus CGA addresses the problem of "Two graphics cards at the same time in an XT" for which CGA+VGA isn't a workable solution.
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Ah, I'm sorry for being unclear in my original post!

Having two graphic cards in the XT at the same time is not an end in itself. Rather, I was wondering if it would be possible to specifically have a VGA card (for connecting to a relatively widely available and cheap VGA monitor) and a CGA card (for using the composite mode for certain games) to easily switch between, without having to open the case every time I want to use the other one. I've learned now that that is not possible.
 
There do exist dual-head cards that support CGA, MDA, VGA, and EGA in a single card. They have a 9 and 15 pin connector and switches on the back to select video mode. It would require a reboot between video changes, but you also wouldn't have to open the computer up or anything. I don't always know how good the compatibility is with every screen mode on these things, as VGA was always fine for CGA/EGA emulation in my use cases.
 
sqpat said:
There do exist dual-head cards that support CGA, MDA, VGA, and EGA in a single card. They have a 9 and 15 pin connector and switches on the back to select video mode. It would require a reboot between video changes, but you also wouldn't have to open the computer up or anything. I don't always know how good the compatibility is with every screen mode on these things, as VGA was always fine for CGA/EGA emulation in my use cases.
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Yes, I saw a couple of cards like that on Ebay. None of them seemed to have composite out for CGA, though, only 9 pin digital.
 
By the time VGA (and really EGA), rolled around, composite support was long forgotten in PCs. No one wanted that for their office computer. I don't think there really is a VGA card with CGA composite compatibility unless you make one, and obviously no historic pair of cards exist.

I think the true CGA composite PC requires a true CGA card sans VGA in the system. It'd probably be better off using the XT for the CGA composite games, and sticking the VGA card in something like a 286 and have two PCs. You can get a CGA-to-VGA adapter for the other games that aren't meant for composite. It's probably the only practical way to go about playing games meant for the PC in that way.
 
Agent Orange said:
Why not go with one of Hercules Graphic Cards? Worth investigating.
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I agree. HERCULES cards have a very unique graphics which lets you play old DOS games in. A whole new way. Im going to be setting up a 5170 with hercules soon and hopefully loading jt up with Every hercules game I can find.
 
On my Tandy 1000RL, I did exactly that. I added a VGA card and added some wires to the VGA ROM that allows switching it on/off. Works fine.

Not sure if it would work in an XT as well, but I don't see why not. Though the Tandy deactivates it's graphics when a VGA card is found...
 
I wouldn't imagine the composite circuitry on the cga card is complicated. Can it be generated via an adapter from the 9 pin?

- Patrick
 
sqpat said:
I wouldn't imagine the composite circuitry on the cga card is complicated. Can it be generated via an adapter from the 9 pin?
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How would that solve the issue? The CGA card must be working in either case.
 
Timo W. said:
How would that solve the issue? The CGA card must be working in either case.
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Let say on a dual head card.

EDIT: Alternatively, off a feature connector on the VGA card, but I feel like that wont be compatible with CGA?
 
I highly doubt that, as VGA cards normally do not even support Hercules (except very early ones). That's why they can co-exist with a Hercules card, as there are no resources that can clash.

CGA, EGA, and VGA can work with MDA/Hercules as a second card, and that's it. No other combination works out-of-the-box.
 
Some of the dual-mode VGA cards does have drivers that let you switch mode in software, without rebooting. Many of them also emulates CGA to VGA with double-scanning (although not 100% compatible with all games).

But yes, if you want the composite out you kinda need more native CGA hardware, and the most advanced cards you get there would be something like the non-VGA/EGA card ATI Small Wonder Graphics Solution.
 
Timo W. said:
I highly doubt that, as VGA cards normally do not even support Hercules (except very early ones).
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Paradise VGA chipsets do. And if you use the VGA1024 utility, they can come pretty darn close to perfect CGA compatibility, at least for 99% of software, including the 160x100 pseudographics mode and the red/cyan/white palette.
 
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