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3,5" Floppy Track 0 Bad fix

Geri

Experienced Member
Joined
Apr 24, 2019
Messages
147
3,5" Floppy Track 0 Bad fix tutorial

I have discovered a method to fix this strange issue. It can be used on old floppy-s. This tutorial will explain how this process work, what tools you need for it, and how to fix these floppys. (Please, do not try to format the floppy if you already can read the contects of the disk, use chkdsk with bad sector repair instead!)

g2UXSNX.jpg


You need:
1. An old 1,44 drive. (if you are doing 720k floppy's, you will probably need an actual 720k floppy drive, or at least set the floppy type to 720k in bios).

2. The floppy drive really has to be old. An USB floppy drive, or a floppy drive built into pentium4 class laptops, will not work. I used a floppy drive from an old 486. This floppy drive is so dumb, it does not even knows when a floppy is inserted, and tries to boot the nothing for 10 seconds when you try to boot the system. This floppy drive does not have a model or part number, its totally noname, and it looks like a 5,25 floppy as its having a large cylinder spinning below the floppy itself. Use this kind of old, dumb device to do this operation. Older the drive, better the result will be. A sighly newer floppy drive maybe work as well, but a modern one will probably wont. Some very old pre-386 era drives maybe will not work, as those are TOO smart. The newer drives are also too smart for this. I have used a Mitsubishi Electric drive. I made a picture from the drive that can be used. Panasonic drives maybe work too, but those are maybe a bit smarter (e.g. they maybe know when you insert or remove a floppy).

mQ5NniO.jpg


qhZZXNA.jpg


6wzY1e0.jpg


3. A desktop computer with a normal floppy connector. You will have to install Linux on this.

4. Another computer with any floppy drive with Windows XP (to test the results in real time).

5. The Linux computer should preferably have Debian Linux.

6. You need a Windows Millenium install disk.

7. Install this on the Linux computer: apt-get install ddrescue

8. You need the bad floppys you want to fix.


The process of repair:

1. You must find a good floppy in the batch (or have one) which then you can make a system disk from Windows.

2. Put the floppy to the Windows computer. Make the system disk. The system disk made in Windows XP is actually a ME boot disk. Copy the format.com from the Windows ME install disk to the floppy. Windows98's format.com WILL NOT WORK.

3. Click the write notch on this floppy, to avoid accidental rewrites. Old and crappy floppy drives will not honor this in certain cases aniay, but it adds a bit of extra security.

4. Ensure all other disk's write notch is in the writable position.

5. Please note: this method will only cure the 1,44 disks, you must restart and redo the whole process for 720k disks separately!

6. Boot the linux computer from this floppy to see if it works.

7. Boot to linux, and make a copy from your floppy using the following command: ddrescue /dev/fd0 /whatever --force
This will create a copy from the contencts of the floppy. Well, not really, linux cant properly handle old floppy drives since years. All Linux tool to handle the old floppy drives are broken since a decade. But this will cough out an image file for you. This image file is sort of broken, and you will not able to boot from it! But that does not matters for now.

8. Do not run anything else on this computer. Yeah, it will crash a few times during the following process.

8. Grab your floppys one by one. Open the notch and check for large errors. If the floppy looks like a babby has touched the disk and you can see fingerprints there, or a velociraptor teared the disk surface up... Then just throw the floppy away, lets not kill the floppy drive at least!

9. Put the floppy disks into the drive one by one, and execute the following command: ddrescue /whatever /dev/fd0 --force
The Linux kernel will blidly force all the data into the disk. Actually, it will maybe fail halfway, and the kernel will freeze. Or the floppy drive will freeze. In this case, restart the computer. Once you have finished with a floppy, put the next floppy in, and repeat the process. If you see the floppy drive is not making a reactions, just restart the computer.

10. Repeat this process one more time on every floppy. You actually have to run through on every floppy with ddrescue twice. Lets put the floppy through two cycles.

11. Now we will not need Linux any more. Put out working boot floppy back to the drive, and boot the system.

12. Execute the DIR command!!! You will see the contents of the good boot disk.

12. Enter format A:. Before pressing enter, replace the disk to the first dead one.

13. Execute the command by pressing enter. It will fail, track 0 bad, whatever.

14. AT THIS POINT YOU SHOULD GET a A:\ PROMPT BACK AFTER FORMAT FAILS. ACTUALLY YOU ARE OPERATING FROM THE BAD DISK NOW!!!

15. Enter: MKDIR POTATO

16. Enter: DIR

17. You should see a directory structure with only a directory called Potato

18. Congratulations, you have a floppy disk that works from DOS. If you get abort/retry/fail, then the floppy is toast. You can repeat the ddrescue trickery on it one more time if you really want to save it, maybe it helps...

19. Enter: mkdir potato2 and then mkdir potato3 and so on. Create at least 10-20 directory to see if its realible.

20. Dir command should list all the potatos.

21. Take out the floppy. DO NOT PUT THE SYSTEM DISK BACK INTO THE COMPUTER. The firmware of the floppy drive is already sort of crashed, if you put the boot disk back, it will erase its track0 even if its having a write protect noth enabled state!!!

22. Go to the Windows computer, put the floppy in. If you are lucky (80%), you can open it even in that computer. It will cough for a few (5-10) second to display the contents, but what is important is the fact that the floppy works.

23. Right click on drive A, run disk maintenance, run chkdisk. Select fixing, and fixing the bad blocks too. Let the process run. This is may will run, may will glitch out.

24. DO NOT TRY TO FORMAT THE DISK ANY MORE, IT WILL TOAST IT.

25. If the chkdisk can cure the disk, we will see a bounch of FILE.CHK-s in the size of about 400 kbyte. Erase them, we dont need them.

26. Repeat the process from 10 on every floppy you have. Please note that after each one, you will have to restart the computer!

If it was working for you, you can donate dogecoin: DJ9EXycXXTKkqDZHgyXN7zp858uBkh9txH
or bitcoin cash (or other forks) 14eBUkMq9zBD9382m9L31GvYnaDv8BTZUc

2X6KANl.jpg
 
Or just use a bulk tape eraser to remove all traces of formatting from the disk, then try formatting it again.
 
i am interested to try that out once. however, i dont have any.
 
Almost any magnet will do the job, especially one of those powerful neodymium magnets that are found inside dead hard drives.
 
A few years ago, i have scavenged magnets from old hard drives, totally 6 or so piece. Next time i will try it on the dead floppy disks to see the effects.
 
Almost any magnet will do the job, especially one of those powerful neodymium magnets that are found inside dead hard drives.

I can confirm I almost always recovered un-formattable floppies by bulk-erasing them with magnets. I use the ones from old magnetrons (the microwave oven ones).
I don't use 3.5" disks however, I've just had success with 5.25" ones. 3.5" floppies are too new for the typical hardware I love to play with :)

Frank IZ8DWF
 
I've had some success using brute magnet force to wipe floppies with bad track 0 and get them to format, but it seems like the track 0 always ends up failing again after they get put back into service for a while. Now I just trash them
 
So the TL;DR of the OP is they recommend Linux "ddrescue", with the usual precaution not to bother with lobotomized USB floppy drives.

Both DOS and many DOS/Windows disk copiers do crap themselves if the boot sector or one copy of the FAT is not readable.

But the "high tech" way to archive these things these days is something like a Kryoflux or Supercard pro. Some times the various decoders can decode sectors that DOS barfs on.

Writing data back to a possibly damaged disk is not a great idea. Using a degausser or magnet to wipe the disk just clears any extra "noise", that might make a marginal disk seem a bit more readable until sectors are re-written a few times.
 
I used this software

http://www.win3x.org/win3board/viewtopic.php?t=25640

to format bad track 0 disk, and usually works - but don't expect these disk to be reliable ...

In these days I'm checking a bunch of old disks and my basic rules are :
Visual inspection for scratched/dirty surface and toss away what's bad (... or clean them if they're just dirty)
DIR A: and if i can see files then check disk condition with SCANDISK or NORTON DISK DOCTOR.
If they're fine check for viruses (found NYB.A in dozen of disks... and actually burned an infected BOOT DISK IMAGE as a bootable CDROM too ...)
Backup them if I need them or
FORMAT A: /U if there's nothing good on them. IF this fail I use MYFORMAT or downgrade the disk to 720K.
I tried also to "low level format" some disk with a very strong magnet taken from a broken hard disk but got very
strange result.

I actually backupped bad disk with error in track 0 with this software
https://dmde.com/download.html
(there's actually a DOS version in 2019!) wich can skip bad sector and copy good ones into a image file.
 
I used this software

http://www.win3x.org/win3board/viewtopic.php?t=25640

to format bad track 0 disk, and usually works - but don't expect these disk to be reliable ...

In these days I'm checking a bunch of old disks and my basic rules are :
Visual inspection for scratched/dirty surface and toss away what's bad (... or clean them if they're just dirty)
DIR A: and if i can see files then check disk condition with SCANDISK or NORTON DISK DOCTOR.
If they're fine check for viruses (found NYB.A in dozen of disks... and actually burned an infected BOOT DISK IMAGE as a bootable CDROM too ...)
Backup them if I need them or
FORMAT A: /U if there's nothing good on them. IF this fail I use MYFORMAT or downgrade the disk to 720K.
I tried also to "low level format" some disk with a very strong magnet taken from a broken hard disk but got very
strange result.

I actually backupped bad disk with error in track 0 with this software
https://dmde.com/download.html
(there's actually a DOS version in 2019!) wich can skip bad sector and copy good ones into a image file.

what method to clean the surface of a disk?
 
what method to clean the surface of a disk?

Well, I tried to clean a few disks just using cotton swabs and alchool, and a lot of patience.
I spent most of the time on a single disk, that was actually scratched and unreadable, and
I managed to get a clone image, with several errors, but good enough to save some files
I needed.
BTW most of the disk I'm trying to recovery contains no valuable data, I just want to reuse them
after formatting.
There are a small number of them that I will like to recover but for now I'm gathering experience...
 
Isn't there some dangerous material in microwave magnetron's? Might be worth a warning to some who are unaware of it.
 
No, I don' t think so--if you have a citation that says so, please post it here. The magnets are ordinary ceramic magnets. The rest of the magnetron is mostly glass and assorted common metals.

Of course, there's a small amount of very dangerous vacuum under the glass--it could mean the end of the universe as we know it if it escapes. /s

Please, do the research.
 
In the insulators attached to the magnetron itself in tiny amounts. The heater also contains trace amounts of thorium oxide.

What are you going to do, pulverize the thing and inhale it? Fluorescent lamps contain amounts of the same material--and heaven forfend--mercury!

The magnets are exterior to the magnetron itself and are quite simple to get at. In the article cited, simply remove the screws on either side of the cage and the assembly will come apart, leaving the magnetron itself intact. From WikiP:

BeO is carcinogenic in powdered form and may cause chronic beryllium disease. Once fired into solid form, it is safe to handle if not subjected to machining that generates dust. Beryllium oxide ceramic is not a hazardous waste under federal law in the USA.

I've got a box full of mercury-wetted relays. I suppose that I should call the hazmat team in... And oh my, I've got a box full of 4' fluorescent lamps...
 
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