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I have a CD which isn't properly finished. I have to recover the data from it. Machines react kind of differently for it but none of them can access it. I can't even DD the data off...

dd if=/dev/sr0 of=movie.iso
dd: opening `/dev/sr0': No medium found

Is there any more tool in linux to do this?

gekkpeng
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2 Answers2

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Try cdrecord -fix. This will write a TOC to the end of the CD.

longneck
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CDs and other optical media aren't formatted before writing to them. So the media itself is now unfinished, the drive can not understand what is on the disc because the information necessary to interpreting the media is physically missing. No normal drive will be able to make heads or tails of that. Your only option is that the data is gone, or send it to a recovery company who will essentially scan a picture of the disc and interpret that (there may be other methods, but this is the one I'm familiar with).

Just to help contrast the situation, optical devices are not like modern hard disks. Modern hard disks have a permanent formatting from the factory (Don't confuse formatting with placing a file system on a disk drive, most operating systems conflate the terms even though they are technically very different). When you write data to a HD you are not laying down the formatting information. No matter what data you put on a HD the HD will still have that permanent format information, so it can read any part of itself.

Vaguely relevant: Magnetic tapes (DDS, LTO, DLT, etc) come with a factory formatting, writing data to the tape doesn't lay down new formatting. But most tape drives will allow you to "erase" a tape, which will destroy the formatting (making it totally unusable).

Chris S
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