Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!ames!killer!csccat!jack
From: jack@csccat.UUCP (Jack Hudler)
Newsgroups: comp.sys.ibm.pc
Subject: Re: IRQ2 used by VGA?
Message-ID: <2606@csccat.UUCP>
Date: 31 Oct 88 15:25:16 GMT
References: <5206@watdcsu.waterloo.edu>
Reply-To: jack@csccat.UUCP (Jack Hudler)
Organization: Computer Support Corporation. Dallas,Texas
Lines: 23


In article <5206@watdcsu.waterloo.edu> dmurdoch@watdcsu.waterloo.edu (D.J. Murdoch - Statistics) writes:
<I just bought a Microsoft bus mouse for my XT clone.  (They're offering an
<excellent educational discount.)  When installing it, I found that the only
<interrupt line I had free was IRQ2, which is listed as conflicting only with
<an EGA and a network adapter.  I don't have any plans to get a network adapter,
<but would like to upgrade from monochrome to colour.  Does the VGA also use
<IRQ2?  If so, is it possible to double up devices on IRQ lines without
<killing everything?
<
<Thanks for any help.  If it's email'd, I'll summarize and post.
<
<Duncan Murdoch

	The EGA or VGA doesn't use the IRQ2 unless you enable it.
	So to answer your question is use the IRQ2 interrupt for
	the mouse, odds are that even if some program enabled it
	the EGA/VGA Vertical Retrace interrupt would interrupt only
	once and without something out there (i.e. program) to
	re-enable the Vertical Retrace Interupt it would not
	present a significant problem.
-- 
* OS2, what DOS should have been!