In the early PC-DOS days, IRQ's 2, 5, 9, and 10 were often unused and available for other things, quite often for serial ports. IRQ7 was traditionally used for the parallel (PIO, or printer) port.
Ok, I remember about the printer IRQ now...it's difficult to remember, seeing that most printers are USB now. I think when I actually got a 2nd computer to get on the net...I took the printer off of my BBS anyway =] and just had one modem in there. Eventually, IRQ5 got abducted by sound cards, with IRQ's 2 and 9 as
options. IRQ's 2 and 10 were common options for bus mouse cards.
Now as I recall, the old soundblasters used 2 IRQs? I'm not 100% sure, but I remember something about that...it made it difficult to put 2 modems on a machine.
workplace because PC's with sound cards were rare. Also a common practice was to turn off one serial (COM) port and reclaim its IRQ for something else.
I remember that too...I had a friend...he ran a BBS also, he showed me a lot of different things in DOS to get around IRQ limitations and such. He also introduced me to Desqview and QEMM, because a BBS on 4 megs of RAM doesn't run LORD and BRE very well, and DOS isn't a multitasker. Ahh, those were the good old days. #-o And I thought I was the only one around that thought that way =] -- Gossamer Axe [EMAIL PROTECTED] http://gypsy.sytes.net/ -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
