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When I tried to download it, I got a "401 Authorization Required" 
error message.  any ideas?

Bob Cham
MacBook Pro running OS 10.6.8



>I have had some luck recovering data from burned discs using the 
>command-line tool ddrescue:
>https://www.gnu.org/software/ddrescue/ddrescue.html
>
>A version for Mac (OS X 10.5+) is available here:
>http://tinyapps.org/blog/mac/200808220700_ddrescue_for_leopard.html
>
>ddrescue doesn't itself do any error correction, but rather extracts 
>the readable data bit by bit --
>often at many times slower than real-time, depending on the number 
>of errors -- to a disc image
>file representing a complete read of the disc minus any bits that 
>are missing.  You can then mount
>this disc image (OS X will do this natively) as if it were a CD-R 
>and use the CD ripper/audio
>extractor/error correction software of your choice on it, which may 
>be more successful than on-
>the-fly correction from the optical disc itself.
>
>Another feature of ddrescue is that you can run it multiple times on 
>the same disc, and each time it
>will go back and try to fill in the bits that are missing.  That 
>obviously won't work with data that's
>completely gone, but sometimes can recover data that didn't read 
>correctly for some other reason. 
>And these subsequent reads are faster because the program is only 
>addressing the missing data,
>and skipping over the parts it has already successfully captured.
>
>But the best case will be if you have two copies of the degraded 
>disc.  In this case ddrescue can
>scan both copies, merging them into one image that will probably be 
>error-free, since it's unlikely
>both discs have degraded in exactly the same places.  And again, 
>only the missing bits are read
>from the second disc in an attempt to fill in the gaps. 
>[Disclaimer: I haven't used this particular
>feature of ddrescue myself yet, but am describing it based on 
>information on the project's web
>page.]
>
>It's a bit more involved than popping a disc in, firing up iTunes 
>and clicking "extract," but it's
>worked for me when nothing else would.
>
>- Aaron
>
>--
>Aaron M. Bittel
>Archivist-Librarian/Digital Projects
>UCLA Ethnomusicology Archive
>
>!DSPAM:639,520183ea176641874312152!