Date: Tue, 20 May 1997 19:44:00 +0100
From: Matthias Paul <PAUL-MA AT reze-1 DOT rz DOT rwth-aachen DOT de>
Subject: Re: Need a Boot Sector Saver
To: opendos AT delorie DOT com
Reply-to: Matthias DOT Paul AT post DOT rwth-aachen DOT de
Message-id: <14368760621@reze-1.rz.rwth-aachen.de>
Organization: Rechenzentrum RWTH Aachen
Content-transfer-encoding: 7BIT
Precedence: bulk

Someone asked:

> ... I'm just having trouble with one of the steps. It says to "use 
> some tool to save the boot sector." Using an internet search, 
> I found one, but the file it created wasn't the right format for 
> GRUB.  Where can I get one that will?

You can save/restore the Master Boot Record (MBR) of a harddisk by 
using special options from the FDISK main menu of Novell DOS/OpenDOS.
When writing/initializing a new MBR, the old MBR will be saved in 
a file C:\OLDMBR.BIN, which can be restored later.  (MS-DOS FDISK 
only provides a function to write a generic new MBR by undocumented 
option /MBR, not yet supported by NWDOS/COD FDISK's parameter 
interface.  Note, that if giving this option, MS-DOS' FDISK directly 
performs this function without any user interaction.  Some versions of
PC-DOS and OS/2 also support the /MBR parameter, and newer versions 
of OS/2 Warp support a /NEWMBR option.)

To save/restore a new boot sector of a logically drive (not the 
MBR!) you can use DEBUG, as shown in NWDOSTIP.TXT from MPDOSTIP.ZIP 
(replace ??? by the drive no, zero based, e.g. A: = 0, B: = 1, 
C: = 2, ...)): 

 Writing a drive's boot sector to a file:
 
  DEBUG
  -L 100 ??? 0 1
  -Rcx=200
  -N \bootsect.bin
  -W
  -Q
 
 Restoring a drive's boot sector from a file:
 
  DEBUG \bootsect.bin
  -W 100 ??? 0 1
  -Q

Answers to related questions:    

1. BTW, some days ago, there has been a question, if NWDOS/COD's 
   FDISK automatically formats a drive after creating a partition. 
   Yes, it does similar to FORMAT /X.

2. Someone stated, that Windows95b does not allow to boot old
   MS-DOS from its dual-boot menu any more.  This is true, since 
   the boot sector code was changed to support hugher drives, 
   I think.  After patching the ID string in the boot sector from 
   "4.1" back to "4.0", one should be able to boot old MS-DOS even 
   under Windows95b.  However, as far as I know, OpenDOS cannot 
   yet be booted from the dual-boot menu of either Windows95.
 
 Matthias   
 
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