Re: [TCLUG:18254] Dual headed video cards

[Callum Lerwick <lerwick@tcfreenet.org>]

> As an aside, in the old days the PC BIOS would not allow multiple video
> cards.
> When did this change? Or was my crappy Postive ibm clone just junk?

PCI lets it happen. ISA/VLB cards were fixed adresses. Plug in more than
one and they conflict. Though there was specialised ones that you could
mess with resource ranges. PCI provides a nice standard way to set
resources. Along with the fact that manufacturers started designing chips
with multihead in mind. (Mainly, you have to be able to disable 'legacy'
support so that only one card is going for the VGA adresses...)

Note that the system BIOS still only supports one card. ;) My secondary
video card isn't even listed during boot along with all my other PCI cards,
which seems odd...