Unable to access h/d due to fdisk error

Unable to access h/d due to fdisk error

Post by Michael C Willia » Tue, 09 Jan 1996 04:00:00



I have done something very stupid whilst setting up linux on my pc (which
is a P100, 16M RAM, 1x850MB Western Digital Caviar AC2850 h/d and 1x730MB
Western Digital Caviar AC2730 h/d, running WIN95).
I set up linux ok on my secondary disk and then idiotically tried to
change the SYSTEM ID of my primary h/d from UNKNOWN to DOS 16bit=>32M
using linux fdisk command 't'. I am running Ontrack Drive Manager's
Dynamic Drive Overlay on the primary disk and because I changed the
SYSTEM ID, I now get a DDO error when I boot from that disk. As soon as
I had done the act, I realised the mistake and now I need some way of
changing the SYSTEM ID back to something the DDO will recognise.

Please help as I (even more stupidly) have not got a backup!

Michael C Williams

 
 
 

Unable to access h/d due to fdisk error

Post by To » Thu, 08 Feb 1996 04:00:00



Quote:>I have done something very stupid whilst setting up linux on my pc (which

I honestly believe we all have innocently trashed a drive or two in our days.
It must be one of the hazards of experimenting.

Quote:>I tried to
>change the SYSTEM ID of my primary h/d from UNKNOWN to DOS 16bit=>32M
>using linux fdisk. I ... now get a DDO error when I boot from that disk.
>I ... now need some way of
>changing the SYSTEM ID back to something the DDO will recognise.

The skies are becoming dark.  A brainstorm is approaching.

DDO uses a previously unused ID code so that it knows how to manage the drive.
Specifying a known format puts a snag in the works because it's not DDO's
format.  If you were presented with the code in numerical format (and you
still remember it), fdisk may let you change it back to that unknown format,
thereby resurrecting the drive.

Otherwise, here's what I'd try (and I've plenty of experience in the trying
game):
        1) Sacrifice the Linux drive.  It must be a guinnea pig.  Since it sounds like
the Linux installation is very new, reinstalling from the source seems a small
price to pay.

        2) Use Disk Manager on the secondary drive to partition it similar to the
primary.  This is assuming the secondary drive could use the services of Disk
Manager, and that Disk Manager will treat it like your primary.

        3) Boot Linux from floppies, log in as root, and run fdisk on the secondary
drive.  With any luck, the system ID is similar, if not identical, to the
primary's.  Quit fdisk.

        4) Trial-and-error period.  Rerun fdisk on the primary drive, and change the
ID to that found on the secondary.  Reboot to DOS and see if you regain access
to the drive.

        5) Should you not get the primary back, write down the system ID used, then
cross it out (it failed, right?).

        6) Now pick a number, either greater than or less than the previous ID's used,
but increment by one.  For example, if the first ID tried was A4, choose
either A3 or A5.  After two more attempts, your options would be A2 or A6, and
the list shows A3, A4, and A5 failed.  After two more, A1 or A7, with A2
through A6 failed.  My theory is that the proper ID should fall within a
limited range of the secondary's ID, given the same program was used to create
both drives.

        7) Go to step 4.

Quote:>Please help as I (even more stupidly) have not got a backup!

Tape drive prices are dropping, and it's been invaluable here.  Just a hint; I
started without a backup, too.