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Mail Archives: djgpp/1995/02/28/13:04:08

From: Charles Sandmann <sandmann AT praline DOT no DOT NeoSoft DOT com>
Subject: Re: One More Confused Interrupt Question
To: djgpp AT sun DOT soe DOT clarkson DOT edu (DJGPP Mailing List)
Date: Tue, 28 Feb 1995 10:53:17 -0600 (CST)

Okay, I can't resist, I have to add some info items to the hardware
interrupt discussion.

1) When running under GO32, you only see interrupts which occur in 
   protected mode.  When running under DPMI, you see *ALL* interrupts,
   even if they happened in real mode.  In V2, you see the DPMI type
   behavior, of course.  If you want to see all the interrupts, run
   under DPMI.  A free DPMI is available.

2) The interrupt reflection overhead between the two modes can be an
   issue, but only in extreme cases.  My 486/33 can handle around 10K of
   these reflections per second, which means I can handle a 1024Hz clock,
   saturated disk I/O and network traffic and still not lose any interrupts.
   On a 386SX/16, a 1024Hz clock may consume 1/2 of your available cycles.

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