[comp.sys.ibm.pc.hardware] Where's the track and head count on an XT disk?

dmurdoch@watstat.waterloo.edu (Duncan Murdoch) (09/18/90)

A friend of mine recently misplaced a lot of data on a big disk, because
a hardware conflict somehow messed up the track and head count that his
Western Digital XT controller wants to use.  I've also got a Western Digital
controller.  I don't know the model number, but the BIOS has a 07/15/86 
copyright and the low-level formatter is WX2 revision 1.0S.

I've been looking through my BIOS trying to figure out where the track and
head count are stored, hoping that we'll be able to patch up my friend's
disk.  (Western Digital tech support suggested reformatting the disk, but
he's got stuff there he doesn't want to lose.)  

Someone told my friend that XT controllers have an unaddressable
track before track 0, and that's where they keep things.  I can't tell
if that's true or not, but I do see it storing something in the first
sector, after the partition table.

Does anyone know for sure where this kind of controller keeps the setup
information?  More to the point, do you know how to patch it without doing
a reformat?

Any help would be greatly appreciated.

Duncan Murdoch
dmurdoch@watstat.waterloo.edu

jc58+@andrew.cmu.edu (Johnny J. Chin) (09/18/90)

All XTs (at least the ones I know of) have controller that store the drive
parameters on track 0, head 0 of the hard drive itself.  If some program
had messed up this information on the drive, you're almost out of luck.

There is one thing that may work ... obtain a copy of SpedStor from Storage
Dimensions (for your drive or the general version).  Use SpedStor to define
the drive type BUT DO NOT INITIALIZE THE DRIVE or you'll lose everything.
NOTE: This procedure only works sometimes!

You could try to use DEBUG and STOP THE PROGRAM when it goes to INITIALIZE
the drive.  THIS IS VERY DANGEROUS THOU, YOU CHANCE LOSING ALL THE STUFF!
(not that you can read it now anyway).

I hope this information helps you.
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Disclaimer:   The views expressed herein are STRICTLY my own, and not CMU's.