[tlug] Program to Save / Remap Bad Sectors

["Stephen J. Turnbull" <stephen@example.com>]

CL writes:

 > I have a 1Tb HDD, formatted in NTFS -- and filled to within 7Gb of max 
 > capacity with complete seasons of Doctor Who -- that is getting wonky.  
 > I am trying to clone the contents on to an external 2Tb drive which is 
 > also NTFS

Just to confirm, you need to read it from Windows?  Otherwise, life
will be easier if you reformat the disk to anything Linux likes
(AFAIK, Linux still does not like NTFS very much).

However, there is this project:

http://www.tuxera.com/community/open-source-ntfs-3g/

The ntfsclone utility (not documented online as far as I found, I took
a look at some of the manpage sources in the distribution tarball)
seems to be the ticket.  Use the -rescue option.

The rest is tl;dr but I'd already written it before I found ntfs-3g,
and it may be of value to someone.  A couple of quick ex post
additions are enclosed in square brackets.

 > I keep running into bad sectors and stopped copy.

Bad sectors on read, I hope.  (Well, sort of.)  If you're seeing bad
sectors on write, you really should exchange the disk while it's still
in warrantee....

If you were copying to a Linux filesystem instead of NT, I'd say use
dd with the conv=noerror,sync options.  [This appears to be equivalent
to the ntfsclone -rescue command recommended above.)

 > Back in the days when you could cram a huge 800Mb into a full height 5 
 > 1/2" Maxtor HDD, there were DOS-based programs that would allow you to 
 > fix, move, and, alternatively, remap bad sectors

It's not possible to "fix" or "move" a bad sector that is causing read
errors.  What can be done is (maybe) to read part of the sector[1], to
write that data to a different sector, and to update the file metadata
to point to the new sector rather than the old one.  Then it *may* be
possible to reconstruct the unreadable data (but probably not for
MPEGs or whatever format your Dr. Who files are in, sorry -- you're in
for that glitching, popping experience I suspect).

If you're getting write errors, you can use fsck or mk*fs to allocate
those bad blocks to a pseudofile (pseudo because it isn't listed in
any filesystem directory and doesn't contain any content, just ties up
the blocks so they won't be allocated for data storage.  This works
(to one degree or another) with e2fs and descendants, reiserfs, and
FAT file systems at least.  [Also ntfs-3g AFAICT.]

Steve


Footnotes: 
[1]  Note to those who already know what I'm talking about: I'm
deliberately fudging the difference between "sector" and "block"
because I'm lazy.