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/ddrescueddrescue 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.
Shame about the bitrot though, first time I've come across it.