As it happens it was also possible (although not really practical :-) to run two VGA cards in the same machine. The secondary card was left uninitialised by the

As it happens it was also possible (although not really practical :-) to run two VGA cards in the same machine. The secondary card was left uninitialised by the boot process (since it would have conflicted with the primary), but it was possible to download the ROM, call into the initialisation routine (thus firing up the card and making it the primary), and thereafter switch which card was the one currently mapped into the PC address space to control which display you were writing to. Source: I managed to achieve it once, although only with a great deal of help from people on Usenet...