From:	damon AT redshift DOT com (Damon Casale)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Using DMA for hard disk access?
Date:	Thu, 01 Mar 2001 18:36:06 GMT
Organization:	Posted via Supernews, http://www.supernews.com
Message-ID:	<3a9e955b.2750392@news.redshift.com>
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To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

I'm trying to squeeze the last ounce of speed out of this compression
program, and I'm wondering if switching to direct DMA calls, as
opposed to using the INT13h or INT21h disk read-write calls, would
help things much.  As far as programming in DJGPP goes, I know that it
takes a lot of CPU cycles to switch from protected mode to real mode,
and then back again, to make the interrupt calls.  Would I avoid that
by doing DMA calls instead?

Has anyone tried something like this?  If so, do you have any advice?
I'm not entirely sure how to tell the hard drive what sectors I want
to read or write, but I _think_ I know how to use the DMA I/O ports.
Where would I look for more detailed info on this?

Thanks...

Damon Casale, damon AT WRONG DOT redshift DOT com (remove the obvious)
Yay!  I got a modem so I can dial up my home ISP from work, and access
newsgroups!  ^_^

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