Rob Owens <robowen...@gmail.com> wrote:

> I don't know the answer to your read-only question.  But having done some 
> data recovery in the past, I've found that attaching the drive via USB and 
> sitting the drive in the freezer during recovery can help in situations like 
> this.

I have considered that, but for the moment, I'm getting "not too bad" results 
without.

> Also, besides ddrescue you can also take a look at photorec (part of the 
> testdisk package).

ddrescue will do for me.
It's getting a lot of files complete - and those that aren't, I might well not 
bother with, or I'll accept holes in the recordings. There's a point of 
diminishing returns, and at the moment when I spot it throwing an error I'm 
just hitting ctrl-C and the script goes on to the next file* - I figure I might 
as well get those that recover "easily" first.

* I've also been fiddling with some of the options for quitting on errors and 
such.


Offlist I've been asked if I need the source mounted. In this case, yes - I'm 
doing recovery file-by-file. I usually just run ddrescue across the whole disk, 
but in this case I suspect it'll take a loooooooooong time, and given that it's 
a Seagate** which tend to have "interesting" failure modes which screw up 
ddrescue's methods, I don't think I'd get anything all that useful - and I'd 
have no ideas which files on the recovered copy were complete and which had 
holes filled with zeroes.

I'm now to the point of looking at the per-file logfiles, and moving the files 
that are complete without errors to another directory - leaving me with a 
better idea of how many are still to do. IMO that's the great thing about 
ddrescue - the way you can stop and restart it as often as you like, and it'll 
carry on where it left off (or where you've told it to go to if you fiddle with 
the log file).
Add in a bit of scripting and some options, and it's possible to get it to run 
through quickly, aborting files with errors, and then go back and have another 
run through those when you got the "easy" stuff.

** I don't intend ever buying another Seagate drive ever again. I;d had other 
makes go, but usually the electronics is fine - it's just the disk wearing out. 
Seagate have too many electronics or "crippleware" failures that make recovery 
hard or impossible. An "interesting" feature is that some drives just "stop 
working" once you hit an error - so ddrescue then whizzes through the rest of 
the disk marking everything past the first error as bad. That's just crap 
thinking on the part of whoever dreamt up the firmware spec.

For good measure, got an old PC from the loft to do this recovery with - and it 
packed in. Got another one that I blagged from work as surplus only a short 
time ago, and which was working fine - that doesn't work.

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