Data Recovery Techniques For Dead Zip Disks? 44
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."
Use your brain! (Score:1, Insightful)
A *nix dd looks like it might work but I thought I would ask slashdot
Instead of, oh I don't know... trying it?
Please, anybody who is thinking of submitting an Ask Slashdot, read How To Ask Questions The Smart Way [catb.org] first. It covers things like RTFA and STFW, which a lot of Ask Slashdotters seem to be unaware of.
Re:Use your brain! (Score:3, Informative)
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.
Re:Use your brain! (Score:3, Informative)
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 d
Re:Use your brain! (Score:5, Informative)
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?
Give it a go with dd (Score:2)
With your ZIP 250, you have the added advantage of having destinaiton media that has the exact same geometry as the original
Spinrite (Score:5, Informative)
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 [grc.com] has some more information on Spinrite and Zip Disks.
If you can't read the disk at all, I think you are screwed. Sorry.
Re:Spinrite (Score:2)
Well, the information might be useful to someone at least.
Re:Spinrite (Score:4, Informative)
Despite the bullshit on the Gibson Research website, [the software] 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.
You should be able to whip something up with dd to do something similar. Make n number of dd images. Write a quick perl program to read through all the images at the same time, figure out if the bit at i position is more likely to be a one or a zero, and write the more likely bit to a new image file. Then mount the new image file as a loopback device, or copy it and try to run some file checkers on the copy.
Re:Spinrite (Score:2)
dd does not investigate hardare. dd does bit copies and does not even do error correction. Spi
Re:Spinrite (Score:2, Interesting)
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:
Re:Spinrite (Score:3, Informative)
Spinrite tries reading stuff in different order each time so that the head momentum, and thus positioning, is a bit different on each read attempt. It then analyzes the data that it read and tries to figure out the whole thing (incl. parity, likelyhood of real world ascii data, etc) not just averaging the bits.
Re:Spinrite (Score:2)
Re:Spinrite (Score:2)
dd just reads sequentially and will probably just return the same garbage each time.
My bad. The principle is sound though -- perhaps accessing the bad drive directly through perl, and grabbing the hdd testing routine from badblocks, it would be possible to do an analysis of the drive similar to the GRC's software.
Re:Spinrite (Score:1, Funny)
Re:Spinrite (Score:3, Insightful)
FAT16 (Score:2)
Re:FAT16 (Score:1)
Try Spinrite 6.0... (Score:2)
Re:Spinrite (Score:2)
I have to add my obligatory "iomega sucks" statement in here. Click of death is real, whether they acknowledge it or not. Proprietary removable media in general sucks anyway, especially when you have common formats like CD's and DVD's.
Re:Spinrite (Score:2)
You are right; reads happen at the sector level. However, they are normally discarded in the case of a bad read (and a read is re-attempted). Spinrite claims to access the hardware at a lower level so that it stores in memory the result of the defective read. When this is done repeatedly, theory has it that hopefully it will get a perfect read at least once, or, if that
ddrescue (Score:2)
Re:ddrescue (Score:1)
dd_rescue and dd_rhelp have both been a terrific help..
I had to hack dd_rhelp to make it write the temp log to a location other than its default, as I run from read only media, and the default location is the source device with ".log" appended.
In general, many many times better than dd alone
Best and Only Way (Score:5, Funny)
Re:Best and Only Way (Score:1, Funny)
Think just a little before working (Score:3, Informative)
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.
dd usage (Score:3, Informative)
Re:dd usage (Score:1)
Click of death? (Score:3, Interesting)
However, while we're on the topic of GRC, Steve Gubson does have a different utility to cure the click'o'death [grc.com] 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 [grc.com]!
(Speaking of replacing, basic troubleshooting steps would suggest trying it in another drive too...
Re:Be careful! (Score:2)
Yeah, but if you look at the write-up on Gibson's utility you'll see that it can also be repaired.
Comment removed (Score:3, Informative)
Define "die" (Score:5, Informative)
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.
Re:Define "die" (Score:2)
Do you mean, the disk is suffering from the so called "Click of Death", or just that you can't get it to mount? If it's the former, then your best bet is to something like dd or SpinRite to try and pull as much data off the disk as possible.
I have a HDD that's got some rare software on it, and it's suffering from what, as far as I can tell, is advanced Click of Death. It'll boot, sometimes get all the way to the Finder (old Mac), make a loud click, then spin down. Spin up, click, spin down, repeat every
Heat-stressed hard drives (Score:2, Informative)
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.
Kinko's... (Score:2)
dd_rescue to the rescue (Score:1)
LK
The Tao of Backup (Score:1)
http://www.taobackup.com [taobackup.com]
Spinrite has worked every time for me... (Score:3, Informative)
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.