Date: Sun, 13 Jul 2003 22:04:16 +0200
From: "Eli Zaretskii" <eliz AT elta DOT co DOT il>
Sender: halo1 AT zahav DOT net DOT il
To: djgpp AT delorie DOT com
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	(atlas_wang AT yahoo DOT com)
Subject: Re: Hardware Interrupt Latency in Protected Mode?
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> From: atlas_wang AT yahoo DOT com (Wang Yong)
> Newsgroups: comp.os.msdos.djgpp
> Date: 12 Jul 2003 04:18:43 -0700
> 
> But programms running in pure protected mode will not call any BIOS
> funcitons, right?

Wrong, unfortunately: the system will run BIOS code even if your
program doesn't.  For example, the timer tick interrupt runs its BIOS
handler 18.2 times a second.  And some resident software could cause
the disk to seek every now and then.

> Is it possible to get an interrupt response time within small range in
> protected mode? so tough...

I think your problem has nothing to do with PM.  If some BIOS code
disables interrupts for 20 msec, there's nothing you can do to avoid
the latency.  I've seen this happen with pure real-mode data-capture
program I once wrote.