🚀 go-pugleaf

I have the following drives installed:

WDC AC21200H, 1222MB w/128KB Cache, LBA, CHS=1242/32/63, MaxMult=16
WDC AC2420H, 405MB w/128KB Cache, CHS=989/15/56, MaxMult=16

To reduce disk wastage in DOS/Win95 I partitioned the 1.2Gb disk into a
PRIMARY dos partition of 510Mb and an EXTENDED dos partition of the rest.  I
then put another 510Mb Logical DOS drive D: in the extended partition, and
an E: to fill up the disk.

I run Linux on the 420Mb:

Linux version 1.3.20 (root@tsys) (gcc version 2.7.0) #1 Thu May 2 17:40:00 BST 1996

Anyway, I was in the middle on running Word off of D: when I dropped to DOS to
get something done, and found D: to be inaccessible.  I cannot think of
anything which could have caused this corruption which I did.  At one point
I tried to load a file in Word (from C:) and got a blank message box (with
information sign).  With hindsight could this be Word mislaying the filter?

Running DOS fdisk reports the PRIMARY and EXTENDED partitions as being fine,
but the EXTENDED partition is not reported to contain any Logical dos drives.

Booting into Linux, which I configured to mount the DOS partitions yielded:

[Before]
May  7 21:22:09 tsys kernel: Partition check:
May  7 21:22:09 tsys kernel:   hda: hda1 hda2 < hda5 hda6 >
May  7 21:22:09 tsys kernel:   hdb: hdb1 hdb2

[After]
May 12 11:58:10 tsys kernel: Partition check:
May 12 11:58:10 tsys kernel:   hda: hda1 hda2 < >
May 12 11:58:10 tsys kernel:   hdb: hdb1 hdb2
[...] (ignore discrepancies in times!)
May 12 18:20:45 tsys kernel: attempt to access beyond end of device
May 12 18:20:45 tsys kernel: MSDOS bread failed
May 12 18:20:45 tsys kernel: attempt to access beyond end of device
May 12 18:20:45 tsys kernel: MSDOS bread failed

And Linux fdisk presented:

-----8<-----

tsys:~# fdisk
Using /dev/hda as default device!
The number of cylinders for this disk is set to 1242.
This is larger than 1024, and may cause problems with:
1) software that runs at boot time (e.g., LILO)
2) booting and partitioning software form other OSs
   (e.g., DOS FDISK, OS/2 FDISK)
Warning: ignoring extra data in partition table 5
Warning: ignoring extra data in partition table 5
Warning: ignoring extra data in partition table 5
Warning: invalid flag 6620 of partition table 5 will be corrected by w(rite)

Command (m for help): p

Disk /dev/hda: 32 heads, 63 sectors, 1242 cylinders
Units = cylinders of 2016 * 512 bytes

   Device Boot  Begin   Start     End  Blocks   Id  System
/dev/hda1   *       1       1     520  524128+   6  DOS 16-bit >=32M
Partition 1 does not end on cylinder boundary:
     phys=(259, 63, 63) should be (259, 31, 63)
/dev/hda2         261     261    1023  769104    5  Extended
/dev/hda5   ?  485753  486691 1405931926593808   6c  Unknown

Command (m for help):

-----8<-----

Presumably the partition table became corrupted at some point.
(AFAICR, the cylinder boundary warning appeared before)

Is there any way to restore these DOS drives?  I have back-ups or can get hold
of *most* of the stuff on the drives, but there is a lot of precious data and
source code there.  (I only installed Win95 a week or two ago, and had not got
a proper backup system implemented).  I do understand that I could wipe the
extended partition and start again, but I'd prefer not to!

One suggestion I heard was to recreate the DOS logical drives in DOS fdisk,
banking that DOS will then find the old information again.  I have not tried
this for fear of data loss.  Will it work?

.splitbung
-- 
* TQ 1.0 * The 'Just So Quotes'.
"If we do not succeed, then we face the risk of failure."
    	-- Dan Quayle, Vice-President of the United States