In my experience harddisks can develop bad sectors for different reasons:
Mostly a bad sector is caused when a harddisk is suddenly interrupted while it is processing some disk activity.
This can be caused by several occurrences such as:
- resetting your Amiga during disk activity
- a sudden power loss during disk activity
- other sudden interruptions of disk activity
Either of these could possibly develop a bad sector, so whenever possible the above should be avoided.
A bad sector as I understand it consists of a sector whose magnetic levels are undefined/not changable. It's not necessarily physically damaged, just magnetically faulty.
There are some software tools which can magnetically regenerate any bad sectors often even to such an extent that data which was previously lost can be read afterwards as if nothing happened. Specifically there is a tool called "HDD Regenerator" which can repair a harddisk's bad sectors magnetically at the sector level which does work to recover previously unreadable data. The software actually estimates which magnetic level a certain bit on the disk was set to before it became bad. After using this tool the harddisk could still give years of use because the bad sectors are often not caused by wear but by some incident. The tool is developed for PCs but since it works at a sector level which is absolutely filesystem independant it could also benefit an Amiga harddisk when a PC is available.
There is another possible cause for bad sectors on a harddisk which is simply wear. I once opened a harddisk which could not be saved anymore and found that the disk inside was really worn out, it had even developed very fine scratches along it's surface.
Of course, also care must be taken not to let a spinning harddisk be subjected to sudden movement. This could cause the heads to touch the spinning disks and create a scratch or worse.
I read that you got your data back which is really great. I just want to give some extra general info about this subject, also for others who read this thread. :-)
