Re: Help about MBR and BOOT sectors

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Article #356

#356

From: John S. Fine
Date: Mon, 13 Jul 1998 00:00

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Patrice SEPULCRE wrote:
> 
> I' m writing a MBR program which load the boot sector,
> but I would like to put the partition table to an another sector.
> If I move the partition table and lauch the boot sector program,
> the computer sends an error "insert a system disk with the command.com

  Most OS's reread the partition table for themselves in order to
"mount" disk volumes (including the one they booted from).  If the
partition table is not in the expected place and condition then
they fail.

  The best solution is DON'T relocate the partition table.  What
are you really trying to accomplish?  There is probably another
way.

  The method used by many viruses is to hook int 13h and trap all
attempts to read the mbr and return a reconstructed or relocated
mbr instead.  There are some non-virus uses for that trick as
well.  It won't work with OS's that use pmode drivers for low
level disk access.

-- 
http://www.erols.com/johnfine/
http://www.geocities.com/SiliconValley/Peaks/8600/

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From: "John S. Fine" <johnfine@erols.com>
Subject: Re: Help about MBR and BOOT sectors
Date: 1998/07/13
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