Re: problems using int 25h

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#7951

From: Phlash
Date: Tue, 02 Apr 1996 10:34

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Jim Marco wrote:
> 
> I'm trying to write a program (in Turbo C 2.0) that scans the hard disk looking
> for certain file signatures.  I want this program to scan sector by sector, so
> I tried using int 25h via the Turbo C absread() command.  The problem is, the
> program works as intended on drive C: which is a 20 meg PC-DOS 5.0 partition,
> but not on drive D: which is a 300 meg partition (same OS).  The call keeps
> returning a "sector not found" error even for low sector values.  Can anyone
> shed any light on this?  Thanks in advance.

The DOS absolute read/write calls have different parameter sets for big or
small disk partitions (remember those?). I suspect either you, or absread()
are getting the parameters wrong for 'bigdos' partitions (anything >32MB).

Maybe absread() was only intended for manipulating floppy disks :-) I would
write your own using int86x(), and see if the problem goes away...
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Path: arc1-ca.pugleaf.net!dish.news.pipex.net!pipex!bt!usenet
From: Phlash <paa@wimbledon.bt.co.uk>
Newsgroups: comp.os.msdos.programmer,comp.lang.c
Subject: Re: problems using int 25h
Date: Tue, 02 Apr 1996 10:34:04 +0000
Organization: BT Labs - but speaking only for myself
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