🚀 go-pugleaf

In article <1991Mar09.202258.24347@eecs.wsu.edu> wbonner@yoda.UUCP (Wim Bonner) writes:
>In article <gah.668509309@valine> gah@hood.hood.caltech.edu (Glen Herrmannsfeldt) writes:
>>The documentation for DevHlp SetIRQ seems to require vector 9 for IRQ2,
>>and it is supposed to be redirected.  Well, the IRQ2 bus line goes to
>>interrupt line 9.  This may not work for some other reason, I only
>>tested it once.  I am writing this while logged in on COM3.
>
>Actually the way I understand it, you should never try to use interrupt 2 
>directly.  The second interrupt controller in an AT is cascaded off this
>interrupt from the main controller.
>
>If you try to use IRQ2, you are in effect trying to use the same interrupt
>as any device trying to use irq8-irq15.  This includes your hard drive
>controller if your machine is standard in its use of interrupts.

This is true IRQ2 is a cascade of the slave 8259A, however in an AT the IRQ2 
interrupt is NOT tied tied to the bus like the PC. In the AT bus IRQ2
becomes IRQ9 of the slave 8259A. So it is incorrect to say you should never
use IRQ2, all our network cards run on IRQ2.
-- 
Jack           Computer Support Corporation             Dallas,Texas
Hudler         Internet: jack@cscdec.cs.com