From: "Martin Peach" <martin AT loplop DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Interrupts
Date: Sun, 14 Nov 1999 18:02:23 -0500
Organization: Communications Accessibles Montreal, Quebec Canada
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References: <382DF552 DOT 289EBE72 AT virtualis DOT com>
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Alex Mendes da Costa wrote in message <382DF552 DOT 289EBE72 AT virtualis DOT com>...

>but now my system locks up completely when I press a key! Does anyone
>have any ideas? What does the EOI actually do??

The EOI causes the hardware interrupt controller (PIC) to reset its
interrupt flag for that level of interrupt. If you didn't clear the source
of the interrupt (say by reading the keyboard data register) the PIC will
retrigger on the next clock cycle and you're back in the interrupt handler.

\/\/\/*=Martin