Path: utzoo!attcan!uunet!bcstec!evtprp0b!tea6219
From: tea6219@evtprp0b.UUCP (Terry E. Acker)
Newsgroups: comp.sys.ibm.pc
Subject: Re: What's IRQ 2 used for on an AT?
Message-ID: <134@evtprp0b.UUCP>
Date: 1 Jun 90 17:41:30 GMT
References: <749@ucsvc.ucs.unimelb.edu.au>
Organization: Boeing Computer Services Everett Propulsion, Everett WA
Lines: 12

As I understand it:  an XT class machine has only one set of interrupts,
0 through 7.  An AT has two sets, 0 through 15.  To remain compatable with
the older XTs, access to the second set of interrupts is provided through
IRQ2 of the first set.  Typical interrups in the 8 through 15 range are
hard disk controller, AT clock, and 80287.

-- 
|----------------------------------------------------------------|
|Terry Acker                                                     |
|Boeing Commercial Airplanes   ....uunet!bcstec!evtprp0b!tea6219 |
|M/S 03-87,     P.O. Box 3707,     Seattle, WA     98124-0346    |
|----------------------------------------------------------------|