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Data Recovery Techniques For Dead Zip Disks?
Lkmyst writes "Recently I had a Zip 250 disk die on me after the obvious
channels were checked and found to be too expensive for a college student at $200US + I looked to see if there was perhaps another method I could use. A *nix dd looks like it might work but I thought I would ask slashdot to see if anyone out there has had luck with zip disks the drive no longer recognizes."
While GRC's Spinrite is an awesome product (I've been using it for 15 years - since 1.0!) and it can also work on all types of removeable media and most all partition-types (Mac disks must be moved to a PC), I suspect that your disk's problem is more fundamental. :)
However, while we're on the topic of GRC, Steve Gubson does have a different utility to cure the click'o'death on Zip disks.
And while you're at it, you might even be able to get IOmega to replace it even if it's out of warranty!
(Speaking of replacing, basic troubleshooting steps would suggest trying it in another drive too...
dd does not investigate hardare. dd does bit copies and does not even do error correction. Spinrite -- while not a tool for deep analysis of dammaged media -- does have the ability to check for data errors and correct them.
Either I'm misunderstanding dd, or else you are misunderstanding me.
Use dd to make several copies of the disk. Imagine, for argument's sake, that the disk is 20 bits long, and, for argument's sake, we make 3 copies.
The copies then look like this:
dd doesn't need to do error correction, we want it to figure out what it keeps reading. For example, dd keeps getting a different value for bits 4, 5, 15, 16, 17, 18 and 19.
The perl script would then take the images dd gave us, figure out which bits are different, and then figure out the most common result is. For example, for bit #4, 1 is the most common result, so it would "probably" be correct. For bit #5, 0 is the most common result. Etc, etc.