Latest experience archiving crufty disks

edited June 23 in Software

Let me tell you about my latest archiving experience. :# I have not had a disk this bad in quite a while so I wasn't very prepared for it.

I got a set of disks that had some really bad residue on them. It looks like condensation had repeatedly formed and evaporated inside the disk jackets. The area immediately under the opening looked fine, but manually rotating the disk a bit and I saw this:

I ran the disks through my usual water rinsing process, after which they visually looked good.

However when I put a disk in the drive, it made an unhealthy screeching noise. The heads were actually sticking to the surface of the cookie, even though the surface looked and felt fine. Unfortunately this initial attempt put a small nick on the surface.

The last time I ran in to that kind of screeching was from some Wabash disks (the worst brand of disks ever made, they would fall apart when they were new!). I don't know what brand of disks this set really is.

I gave the disks some additional cleaning with a q-tip and water. I was afraid that if the disk was ready to shed its oxide, using Isopropyl alcohol would cause additional damage to the disks. That happened with the Wabash disks.

After a crazy amount of cleaning, there was still some sticking/screeching. I have a faulty 5.25" drive sitting out that I can use to test inserting and manually spinning a disk with drive heads loaded. Even gently turning the drive motor I could feel the heads quickly sticking and releasing. However, I noticed after a few spins the sticking decreased. Presumably the heads were rubbing off some of the gunk.

I eventually gave in an just had at it with the Kryoflux. Surprisingly it read in the data even though there was some small screeching. After a few rotations on each track, the screeching did go away and I was able to retry several times with better results.

The process did put a few additional nicks and scratches on a couple of the disks, and one of the disks did manage to "foul" my drive. I expected this would happen so I made sure to run a cleaning disk through after each try. It left the cleaning disk very dirty!

But surprisingly, in the end I managed to get all of the data off. The 360k drive was able to read the disks fine, although my 1.2mb drive complains about a few bad sectors.

In retrospect I kind of wish I had spent more time manually slowly spinning the disks, and stepping through all of the tracks. That might have picked up more gunk while doing less damage.

The pros use cyclomethicone lubricant to get around this sort of problem, as well as a "baking" process to prevent shedding, but I don't run in to disks quite this messed up every day.

Comments

  • I have a standard dos 5.25" 360k diskette that I am trying to get the original files from. It is not copy protected. It is not nearly as bad as the one shown here, and in fact looks pretty good.
    But after attempting to DIR and XCOPY the files, I got drive errors and it gunked up my drive.
    After cleaning the FDD, it reads ok again, but what is available to read files on damaged disks?
    I don't have Kryoflux or SCP. Are these the only tools?
    Will ImageDisk read the disk even if some of the sectors are bad?

  • The Kryoflux and SCP are the only tools currently on the market that I know of that go deeper than a normal floppy disk controller. There used to be several others such as the Catweasel and the Central Point Transcopy card, but the Kryoflux and SCP are still better for low level analysis.

    I’d suggest reading through my review of disk archival tools: https://forum.winworldpc.com/discussion/7877/a-comparison-of-current-disk-archival-tools Nothing has significantly changed since then.

    Of course, neither of these tools are magic. They won’t read data that is truly destroyed, degaussed, or overwritten. But what they will do is save every last bit that is still readable and enable further analysis or recovery later. You can post flux images and let other people look at them and get advice on how to proceed.

    Between the Kryoflux DCT tool, the HxC disk tool, and the PCE emulator tools, each will try slightly different decoding algorithms that can yield different levels of success decoding a flux stream.

    Errors in sector headers, junk between sectors, odd timing, or sector positioning problems can all be bypassed and data recovered. Although very tricky, small byte sized errors can be manually guessed until a sector CRC matches.

    And if a first read damages a disk, you will still have a flux dump that you might be able to piece together with later dumps to retrieve all of the data.

    As far as recovering data, ImageDisk is not really any better than just copying files. It still goes through the floppy disk controller, which generally is “all or nothing” when a sector error occurs.

    The only advantage to ImageDisk is that it may let you skip the bad sectors and continue reading remaining good sectors.

    However, I generally recommend avoiding ImageDisk or similar when dealing with damaged disks. ImageDisk performs a lengthy “analysis” when it encounters errors. This keeps the disk spinning for a very, very long time and can further damage the disk.

    Anyway, in this specific case I would go back and re-clean the disk with a q-tip and water. Or a full rinsing if you have not already done so. Shining a flashlight on the disk surface at different angles can sometimes reveal minute damage. It does get annoying then the damaged areas are not immediately visible.

  • When it rains, it pours. Just processed a couple more sets of disks. One set, after cleaning, looked almost perfect but the disks were full of errors. Another set looked horrific to the point I expected them to shred themselves, but they worked and read flawlessly.

  • Hello,

    I've read you former topic. Last week I bought a SuperCard Pro device. I will start to archive some MSX games which have copy protection schemes. The MSX disks are the same as plain IBM-PC disks. 300 rpm, 8 sectors per track, 40 or 80 tracks (360Kb or 720Kb).

    Please take a look at my disk preservation page:

    For some reason, I was not able to find/download the graphical HxC Disk Tool, neither the PCE emulator tools. Please can anybody give me a link for that softwares ?

    Thanks.

  • The latest PCE with its tools can be found here: http://www.hampa.ch/pub/pce/pre/

    The HxC software is here: http://hxc2001.free.fr/floppy_drive_emulator/index.html#download (yes, the page is a cluttered mess, search for "HxCFloppyEmulator software v2.1.11.1" if you don't see it.)

  • Yes, MSX FDC seems to be compatible with IBM PC FDC compatible.
    So MSX disk can be read on MS-DOS.

  • edited November 22

    Thanks a lot. I expected a "tools" package, I did'n't realize the tools were inside the emulators, which I don't use. A correction: MSX disks have 9 sectors per track.

Sign In or Register to comment.