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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."
Despite the bullshit on the Gibson Research website, it essentially repeatedly reads bad data and uses some statistical analysis to determine whether each bit was more likely 1 or 0, depending on which came back most often.
This page has some more information on Spinrite and Zip Disks.
If you can't read the disk at all, I think you are screwed. Sorry.
Spinright and other ideas are clearly the way to go, but your disk died because of activity on it (most likely) and more activity with further compromise it.
So:
1. Try all these good ideas suggested here on a different ZIP disk. One which isn't important.
2. Don't proceed with the same drive if you cannot get anything off any ZIP disk with your drive. Find another one. But only do that if the first one is completely screwed, as writing on a disk with multiple drives (for some floppy technologies, not sure about ZIP) is a great way to destroy a disk.
3. Get your dd first: One BIG dd off the whole thing, so you have something to fall back on later, should your work blow up, and the disk turn to cabbage. Not sure of the dd command? Work it out on a DIFFERENT DISK (see #1), so you're not grinding on this disk a bunch of times. Just read it once for the dd, then run spinrite and that stuff to try to do the job right.
Plowing through the dd will be unpleasant, you're only getting it as a last ditch, but get it FIRST.
if you're going to try and recoved data with dd, make sure you dd from the partition itself, ie: /dev/sda4 and use 'conv=sync,noerror' to make sure you don't end up with an image shorted than 250MB due to dd missing out the bits it can't read rather then replacing them with zeros. You may be able to mount the resulting file loopback and see what's left.
Like tinyurl, but one letter less! http://qurl.co.uk/
Hi, You might want to give my program recoverdm a try. It is especially aimed at bad CD-roms, but is also usable for disks (harddisks/floppydisks/zipdisks). It repeatingly tries to read the sector and then uses statistics which outcome is supposed to be the most likely.
www.vanheusden.com - home of Multitail, HTTPing, CoffeeSaint, EntropyBroker, rsstail, bsod, listener, nagcon, nagi
When recovering from damaged media, it's not a good idea to start trying lots of things on the original. There may be a limited number of reads left. You should do your research first.
In this case, I would get a different, known to be good zip drive, and do a dd to get the whole image, and then try to work with just the image; only go back to the zip for a second read if you have to.
However, if it's the latter then you may just have a scrambled partition table which I found was prone to corruption when moving back and forth between Windows and Linux. For some reason Iomega uses partition table entry #4, which I suspect was the root cause of the problem. There also seemed to be a change in geometry between some disks, maybe caused by a reformat or something, I never did figure that one out. Anyway, I eventually came up with the following commands to restore a 250MB ZIP disk to full functionality (change /dev/hd* to suit):
To recreate a valid partition table (you might want to check these values against a known good disk first):
sfdisk -f -q -uS -C239 -H64 -S96 /dev/hdd << EOF
0 0
0 0
0 0
32 489440 6 *
EOF
To avoid some funky issues on Windows which doesn't seem to accept garbage in the first sector of a drive you will probably need to follow that with:
dd if=/dev/zero of=/dev/hdd4 bs=512 count=1
And finally, you can create a pristine new file system with the command:
mkfs -t msdos /dev/hdd4
Obviously if you run the last one then you are not going to have any filenames or pointers left, but the actual data will still be there. In any case, you would certainly want to make a backup image of the raw disk with dd first if at all possible.
UNIX? They're not even circumcised! Savages!
I had a HFS+ partitioned drive start going bad on me (clicking very noisly). I determined that the disk couldn't read one of the first few sectors, but could read most of the drive just fine.
I used dd to try to copy the drive, and got about 20gb out of 30gb of the drive, then the drive completely died.
I tried to use a few disk recovery utilities on the web, to no avail. I found out that there's only two Master Directory Blocks, one at block 2, one at the next to last block. I had lost both.
If I had done my research, I should have pulled the MDB first, and then tried to get the rest of the data. Instead, I have 20gb of garbage. A data recovery company might be able to pull files from the data I have, but I gave up at this point.
Well, what nice, well informed piece of sarcasm.
Maybe it would be a good idea to at least have some knowledge of the subject you're berating someone for BEFORE opening your mouth. You're less likely to get egg splattered.
The original poster did the right thing in asking first. I used to do data recovery and there are times when a media has a very limited physical life left. While less common than with old floppies, even modern magnetic media can suffer from the magnetic material seperating from the disk. If this is the reason for failure then blindly doing something in the hope that it may work could seriously reduce the chances you have for recovery later.
Perhaps you are aware of how much an ass you are by posting as an AC?
It might be the effects of heat stress on the bearings. I've had two HDs die in an old Mac that way. I'd suggest trying to 'dd' a few percent of the hard drive at a time, waiting for it to cool down, and then repeat.
Spinrite is well worth the 90 bucks. Not just for now, but if you have any kind of a disk crash in the future.
I'm cheap as hell when it comes to software. Practially everything else I use is free, except Windows itself. But I had no trouble paying for Spinrite. It's the best software purchase I've ever made.
There's info at grc.com specifically about Zip problems. Check it out.