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Mail Archives: djgpp/2002/11/13/17:15:44

From: sandmann AT clio DOT rice DOT edu (Charles Sandmann)
Message-Id: <10211132215.AA13491@clio.rice.edu>
Subject: Re: Raw disk access
To: djgpp AT delorie DOT com
Date: Wed, 13 Nov 2002 16:15:01 -0600 (CST)
X-Mailer: ELM [version 2.5 PL2]
Mime-Version: 1.0
Reply-To: djgpp AT delorie DOT com

> I know of its existance, but I need to write it myself because it's my task
> for computer study in my University. If there would be sources for that
> thing, it'll of course be good ;-)

I just wanted to make sure you were aware of it.  I'd like there to be
a free source version.

> Does it mean that _bios_disk will fail to read above 1024 cylinder even with
> recent BIOS?

Yes, you will be limited to 500Mb (or 2Gb, or 8Gb based on BIOS).

Newer BIOS calls actually use a sector number to address big disks.

> I'm just asking this, because I don't want to port Linux kernel's ide stuff
> to DOS (because the source takes 800 Kb) and searching for the most easy
> and elegant solution.

Look in Ralf Brown's interrupt list for updated Int 13 calls which allow 
large disk acccess.  You can test if they exist and use them if they do,
else use the old Int13 bios calls (or biosdisk)

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