Xref: news2.mv.net comp.os.msdos.djgpp:6405
From: alaric AT abwillms DOT demon DOT co DOT uk (Alaric B. Williams)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: preemptive multitasking for dj
Date: Tue, 23 Jul 1996 11:13:32 GMT
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Message-ID: <838120311.10346.1@abwillms.demon.co.uk>
References: <Pine DOT NEB DOT 3 DOT 93 DOT 960719160248 DOT 2019A-100000 AT ananke DOT amu DOT edu DOT pl>
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

Mark Habersack <grendel AT ananke DOT amu DOT edu DOT pl> wrote:

>Haven't seen your code but I have a suggestion on the interrupt used. It's
>true that many people use IRQ0 for various purposes but I have never seen any
>package that uses the interrupts the RTC is able to generate (also at
>1024Hz+ I suppose). Don't quote me on that but I think there is such a
>interrupt.

Yes; there are flags one can set in the RTC that generate IRQ08:

a) Once a second
b) At a specific time
c) 1024 times a second

I've got some real-mode code that illustrates this if anyone wants it
(you have to ack ints in a certain and that kind of thing, or else it
seems to crash sometimes...)

> It would resolve many compatibility problems as you wouldn't have
>to take care of other soft using the int (there's good chance that the
>RTC-generated interrupt won't be used). I remember reading some technical AT
>reference on that - maybe this would cure some problems?

Thing is, I'm not sure how many RTCs will still generate this int, and
I've heard that some BIOSes use it internally; in other words, messing
with it can interfere with low level BIOS things like power
management!

Any verification of that???

Regards,


ABW
--
I have become... Comfortably numb...

Alaric B. Williams Internet : alaric AT abwillms DOT demon DOT co DOT uk
<A HREF="http://www.hardcafe.co.uk/Alaric/">http://www.hardcafe.co.uk/Alaric/</A>