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From: hughes@copper.ucs.indiana.edu (larry hughes)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Increasing #task switches per second (> 18.2), help
Keywords: task timer 8253-5 8254.2
Message-ID: <75778@iuvax.cs.indiana.edu>
Date: 3 Dec 90 02:12:06 GMT
References: <4348@dnlunx.pttrnl.nl>
Sender: news@iuvax.cs.indiana.edu
Organization: Indiana University, Bloomington IN.
Lines: 29

In article <4348@dnlunx.pttrnl.nl> filetp@dnlunx.pttrnl.nl (Peter Filet) writes:
>I am developing an Operating System, in the Protected Mode of the i286
>processor.
>Up until now I've used the basic hardware timer interrupt (08H) to switch
>tasks. Unfortunately, this interrupt occurrs merely 18 times per second,
>which doesn't give me much flexibility in assigning time slices to a
>task.
>
>I've been told that the 8253-5 and 8254.2 controllers offer me more
>interrupts per second, thus more flexibility for task switching.
>
>Could anyone please provide me with some (detailed) info on programming
>these controllers ?

You should be very cautious of this; as I recall, the disk drive
routines in the BIOS are heavily dependent on the clock interrupt
(they use it for timing purposes).

I tried to do this a long time ago ('84?) for a real time application,
but gave up trying for this reason.

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