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How to recover data from unrecognized floppies?

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Fire-Flare

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Dec 17, 2009
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Washington State
I have a game I'd like to install but one of the install disks can't be recognized.

Is there a program that can recover or rebuild the data?

My Google search results all seem to promote their own program, what have you guys had luck with?
 
The best solution is to try and find a clean copy of the damaged disk. Even the best tool can't fix sectors that are no longer there.

What is the game? What is the OS to which you will be installing? Some games used special formats that some OSes won't recognize. Sometimes, there is an error in the build list so one disk needs to be given a different volume label. Errata like that can only be found by knowing the game and version.

Unfortunately, just about all the tools I can think of, can make things much worse if applied to the wrong problem. I removed some generic advice.
 
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"revitalizers" will destroy copy protected disks.

Recoverability completely depends on what is wrong with the disk.

If the disk has been reformatted, or other files written on the disk over deleted ones, then nothing can recover it.

If the boot sector has been borked by a virus or something then some tools might be able to fix it.

If it is a physically damaged bad sector, then careful disk cleaning, dumping with a Kroflux, and analysis of the area can sometimes recover data.

If it is copy protection, then it was supposed to be that way and your system might just be incompatible.

Please post a disk dump and perhaps someone can take a look at it.
 
Most formats use a CRC as part of the checking. Most only look
to see if the CRC matches that of the data and report an
error if it doesn't match.
The CRC can also be used to repair a small burst of bad bits.
If you get all the transitions from the disk with a tool like Kroflux,
you can locate the CRC and use it to locate and repair the data
error.
Dwight
 
Here's more information about my situation, the floppy is a 3.5" 1.44MB disk from a 1993 game called Metal & Lace that I bought factory sealed.

There are a total of 8 disks, and the second one has a problem. It gets about 74% through unpacking its data for the installer then gives an error message.

I've tried the disk in my Windows 98SE's LS-120 drive and a USB floppy in Windows 10. Neither can read it.
 
According to online sources, Metal & Lace uses a codewheel for copyprotection so the disks are most likely not protected. Therefore, the likely problem is a bad sector.

Do you have any disk drives attached to a regular floppy controller? I suggest starting with the creation of a disk image on a floppy drive run by a floppy controller. It might be able to catch the sector but it will make sure that a copy of the rest of the data exists minimizing potential damage.

I will let others recommend a tool that ignores CRC errors and reports what data a bad sector shows. I haven't done it enough times to be confident in my techniques.
 
You could always image it with IMD using the "keep bad sectors" option, then spin a new floppy from the image. If the bad sector isn't in an important spot, you could at least get past that diskette in an install. I've also manually patched bad sectors, but it isn't a simple job.

Oh, and use a regular (legacy interface) floppy drive to do the copy under MS-DOS. Neither the LS120 nor a USB floppy offers much fine control--the layer of software that Windows places on top of the interface doesn't make things any easier.
 
You could try Norton Disk Doctor (NDD.EXE) from the 4.5 edition as long as DOS recognizes the disk. But only from DOS and with a real Floppy Drive. If you need a copy, lemme know.
 
I am fairly sure that NDD is the completely wrong tool for this job. It most likely will mark the bad sector as bad after making enough passes over it to scrape it clean off the cookie and then redo the FAT and directories in ways that would make it impossible to reconstitute the original files.
 
It only marks unused sectors as bad -- not used but unreadable ones.

Alternatively he could d/l the entire game. I just did. :)
 
Well, that's the issue with floppies--"unreadable" is a function both of the media condition and of the drive and its associated electronics.

For example, I have a version of Anadisk that keeps reading a sector (without re-seeking) and stops when it gets a good read. I can then write the sector back to disk with no problems.
 
Chuck(G) said:
Well, that's the issue with floppies--"unreadable" is a function both of the media condition and of the drive and its associated electronics.

For example, I have a version of Anadisk that keeps reading a sector (without re-seeking) and stops when it gets a good read. I can then write the sector back to disk with no problems.
Click to expand...

That sounds promising, and quite useful. Is it still possible to get a license?
 
Fire-Flare said:
That sounds promising, and quite useful. Is it still possible to get a license?
Click to expand...

No, AnaDisk was sold off long ago--you can find copies of it around the web, but they don't have the "read until you drop" fix--but you can still go into Sector Edit and keep hitting F2 until you get a good read. Then, just write sector back.
 
If we are determined to read the disk, I'd start by physically inspecting it to see if there are any visible scratches, or any junk on the disk. Clean with a q-tip if needed and if possible. But 3.5" disks don't usually get much junk in them.

If the disk looks perfect, then it very well may be one of those cases where re-reading a bunch may eventually increase readability. For standard formatted disks, I often just use WinImage, try to make a full image, and just mash "R" to keep retrying. If you get a good read, be sure to save it. But on disks like this, it would not surprise me too much if the readability actually improves.

I would not use an LSL-120 for that since those have a different kind of head. Since this seems to be a standard 1.44mb disk, probably the USB drive should be sufficient, although a real FDC and drive would be preferable.

If disk images are downloadable from somewhere, you can also use Winimage to compare the disk. Or other tools to compare extracted files. If they are identical up to the read error, you are probably safe just re-writing the image. (Note that Windows sometimes messes with boot sectors, so those may be different).
 
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