On Thursday 10 September 2020 14:12:08 deloptes wrote:
> William Morder via tde-users wrote:
> > I intend to try all other avenues for data recovery, before I try
> > performing surgery on the hard disk itself. That is a last option, I
> > think.
>
> ok, but if you use the badblocks command to identify potential bad block,
> you could then easily get the filesystem mounted.
>

Ah ha! This sounds promising. 

Looks like I need to do so more research. I only skimmed over those pages on 
badblocks, but if I can get it at least mounted, then I ought to be able to 
recover and move those files to somewhere safe. 

Thanks much, everybody! 

So far testdisk has progressed to about 80% complete, and it says about the 
same thing as before. This was never a boot disk, so I wonder if that is a 
bad sign. Also, it occurred to me that ddrescue's verdict of 2 errors, 3072 
B, which didn't look familiar at first glance, is actually 1024 x 3 = 3072, 
so these 2 errors are only 3 kb? 

Do I need to identify (or calculate the position) of these bad blocks? I read 
something about that. It would be nice if I can get this repaired by some 
more trustworthy and non-human agent. Can I use badblocks to repair or delete 
the bad sectors? 

Bill

This is at about 80%
check_FAT: Unusual number of reserved sectors 4 (FAT), should be 1.
check_FAT: Unusual media descriptor (0xf8!=0xf0)
Warning: number of heads/cylinder mismatches 64 (FAT) != 255 (HD)
Warning: number of sectors per track mismatches 32 (FAT) != 63 (HD)
  FAT12                54360  71 48 54361  11 50      12288 [Firmware]
check_FAT: can't read FAT boot sector
Invalid FAT boot sector
 0 D FAT12                354362 221 37 438923  86 30 1358463954
  FAT12                354362 221 37 438923  86 30 1358463954
  Linux                    0   0  1 182400 253 61 2930272000