I suppose that, strictly speaking, this is not a hardware issue but it seemed to fit best here?
Anyway, I had an old computer. A few years ago I bought an 80 GB disk for it, only to discover that it did not support such large disks. However, IBM provided something called OnTrack Disk Manager from their website. After installing this on the drive I could use the its full capacity.
The drive was installed as hda and the original 6 GB drive was installed as hdb. IIRC, hda contained 2 FAT32 partitions, 2 ext3 partitions and a Linux swap partition.
Then I installed Ubuntu on hdb, because I did not want to mess with my existing systems (Red Hat, Win98, Debian) on hda. However, even though I installed Ubuntu on hdb, it still installed Grub on hda (whithout my permission I might add) and over wrote OnTrack Disk Manager rendering hda useless. I had nothing I really
needed on hda and I had work to do so I just ignored this at the time and went on using my freshly installed Ubuntu system on hdb.
But now I would like try and recover my files. I don't use that computer anymore and I have mounted the disk in one of them external cases that you plug into the USB port. I had hoped that would be enough, since this computer shouldn't have a problem with large disks. But of course it wasn't that easy.
I have tried testdisk
and it finds two of my partitions but gets the sizes wrong. It seems promising, though. It seems that if I could only figure out the (fake) CHS value set by OnTrack I should be able to recover the partitions?
Any hints on how to proceed?