From:	"Charles Sandmann" <sandmann AT clio DOT rice DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: gcc hello.c -o hello.exe 55 seconds to compile and link
Date:	Mon, 3 Sep 2001 22:54:51
Organization:	Aspen Technology, Inc.
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Message-ID:	<3b940a3b.sandmann@clio.rice.edu>
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> It took gcc hello.c -o hello.exe         55 seconds to compile and link.
> This was a one line program. What am I missing ? (or is this normal )

Disk cache.  See FAQ.  

> Some General questions about DPMI server:
> 
> I have been writng embedded applications under turbo c under dos where I
> handle the hardware interrupts from the keyboard, mouse serial ports and
> timer.
> 
> I programmed the timer to interrupt 42,613 times per second. (in the isr I
> do direct i/o to the parrallel port)
> I am using wattcp to exchange tcp/ip packets with an  I/O controller 100
> times/second.
> I get 100 interrups/second from the dma engine that handles the AC97 link.
> serial data is being streamed out to a com port at 125kb.
> 
> All of the above interuppts are being handled by my app.
> Am I barking up the wrong tree trying to port to DJGPP ?

It's hard to tell without knowing how fast the machine is and how much
time you spend in real mode (which would require interrupts to be reflected
back to PM, which is slow).  If you can completely handle most interrupts 
in PM without chaining, and you have a fast machine, you may be OK.

> What is the difference between CWSDPR0 and CWSDPMI ?

CWSDPR0 runs at ring 0 (so you have full access to ring-0 instructions and
protection).  It also doesn't swap stacks on interrupts or support virtual
memory (faster).  CWSDPMI is the ring 3 version which provides more protection 
and virtual memory, but is a little slower.  For maximum speed use PMODE 1.3,
but there are some compatibility issues.

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