[vox-tech] Help - Grub error 21

Peter Jay Salzman p at dirac.org
Wed Feb 23 07:25:44 PST 2005


Hi all,

My computer at work is a WinXP system.  Yesterday I used a Debian Sarge
official installer to make the system into a dual boot system.  Everything
went fine until the reboot.  When the system reboots, I see:

   Grub loading stage 1.5
   Grub loading, please wait...
   Error 21

The system doesn't boot at all.

This is most embarrasing.  I asked for permission to install Linux, and was
given a bunch of reasons why I shouldn't.  After insisting and making my
arguments why Linux would be good for me, they grudgingly said "If you must,
but don't come crying to us if you need support".   Ooops.

I did some Googling, and this is what I found:

   * If the hard drive and CDROM drive are master/slave on the same cable,
     try putting them on separate IDE channels.

   * If the hard drive and CDROM drive are master/slave on different cables,
     try making them cable select.

   * If the hard drive and CDROM drive are master/slave on the same cable
     and set by cable select, try making them master/slave.

   * In BIOS, try setting the IDE list to autodetect.

In other words, "play with it".    :(   Oh brother.  The computer has a lock
on it, but luckily lock picking is a hobby of mine, and I'm confident I can
pick the lock very quickly.

What I also found is:

   * If I want to back off on this, I can revert to WinXP only by booting a
     DOS disk and doing "fdisk /MBR".  I assume this works even for WinXP
     (meaning that WinXP uses the same zeroth stage bootloader that Win95
     did).

   * Error 21 means that grub couldn't find the disk.  Since grub relies on
     BIOS for disk detection, that would explain the "playing with it" steps
     I previously mentioned.

   * For some reason, the Debian boot *floppy* doesn't boot on this machine.
     It gives some uncharacteristically vague error message
     (uncharacteristic for Debian): "Boot failed.  Press a key to retry."

   * Timo's rescue CD does boot on this computer.

   * LNX-BBC boots on this CD.

   * Both operating system are clearly still on the system.

   * System topology is:

         hda: NTFS (winxp)
         hdb: NTFS (winxp)
         hdb: ext3 (Linux)

So that's pretty much what I know and what I think I know.


If anybody has anything further to add to this, I would sure appreciate it.
This is highly embarrasing.  I *really* don't want to eat crow for this.

Thanks,
Peter

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