Kitz Forum
Chat => Tech Chat => Topic started by: sevenlayermuddle on April 22, 2014, 06:08:49 PM
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Bit of a happy adventure today. :)
A friend popped by last night to ask me if I could help them view some photos on a CD they'd been given.
Try as I may I could not see any physical damage to the original disk, but XP wouldn't load it at all, nor would OS/X. Linux let me mount it, it contained a half dozen very large .jpgs dated 2002. But each of the photos got a read error when viewed, displaying just the first few lines of pixels of each photo, then nothing.
So, for the first time, I had an opportunity to try 'ddrescue', http://www.gnu.org/software/ddrescue
ddrescue ran for probably about two or three hours, going through its various phases, after which I mounted the rescue image…. And was pleasantly surprised to find two nearly perfect photos. The remainder, whilst still marred by a few blank pixels here and there (usually in lines), rendered fully once again all the original content clearly visible. Thus I was able to burn a new CD and return to grateful owner. A huge success then, though I say it myself. :graduate:
Shame about the bitrot though, first time I've come across it. :o
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Very interesting. :)
Just one quick query, please. What did you use as the input to ddrescue? The individual JPEG files? The raw CD image? Or . . ? :-\
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Very interesting. :)
Just one quick query, please. What did you use as the input to ddrescue? The individual JPEG files? The raw CD image? Or . . ? :-\
/dev/cdrom, the raw device. All defaults, just input from the raw cdrom & output to a file, you end up with a file similar to what dd would have given you of the original disk had been healthy.
With hindsight I probably ought to have used some more sensible parameters like a logfile but I decided that, since it might take a while, it was best to get something started while I read the manual at my liesure. Then, since it seemed to be doing good things, I just let it continue.
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Thank you. That makes sense. :)
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A huge success then, though I say it myself.
Yes indeed. Well done to you and ddrescue