Get rid of errors on your floppy disks. FIX THEM!

15 posts / 0 new
Last post
Offline
Last seen: 2 weeks 3 days ago
Joined: May 27 2013 - 13:01
Posts: 825
Get rid of errors on your floppy disks. FIX THEM!

Here's a little trick that I have been using since the old days...

Ever encounter a floppy disk that keeps giving you an error in the same sector no matter how many times you format it?

WE ALL HAVE!

The possible solution?

A COMPLETE ERASE.

Also known as Degaussing, it will permanently erase a disk and bring it to a state of no format.

Formatting a disk is an exact process depending on your PC but the end result is the same. The process of formatting will come across the same magnetic problem on the disk and will cause it to get an error in the same place or multiple places. It's caused by a slightly stronger or weaker magnetic field on several spots on the disk.

This is why you should never keep your disks inside your disk drives for too long, and why tape heads need to be demagnetized. When they are not, you will find that the tape head will erase the spot of music where the tape rests on the tape head.

The same goes for disk drives and floppies.

Degaussing will make all magnetism on the disk disappear, and ready to be formatted and be error free.

To do this:

Buy a RadioShack Bulk Tape Eraser.

There are two models, one for cassette tapes, and one for VHS tapes.

I suggest you get the one for cassette tapes since the one that erases VHS tapes cannot be held on for too long and will overheat easily.

The catalog number is 44-232.

Search on Ebay for "bulk tape eraser 44-232" and you'll see many matches. It's not hard to find.

To Degauss your floppy disk, hold it in your hand and turn on the tape eraser and make a circular motion for a few seconds, then while keeping it on, move the tape eraser away from the floppy and then turn it off.

Repeat this on the other side.

I prefer to do this twice on each side of the floppy disk.

This process works on both 3.5" and 5.25" disks.

If afterwards, you still get errors on your floppy disk, then I suggest you put your floppy through a really good and strong paper shredder certified for floppy disks, because at this point, NOTHING in the world can fix the disk.

amauget's picture
Offline
Last seen: 3 hours 39 min ago
Joined: Jan 3 2011 - 11:34
Posts: 331
Re: Get rid of errors on your floppy disks. FIX THEM!

Thanks insanitor !
I used to do the same with magnets.

Offline
Last seen: 2 weeks 3 days ago
Joined: May 27 2013 - 13:01
Posts: 825
Re: Get rid of errors on your floppy disks. FIX THEM!

We're actually doing the opposite, right? Using a magnet would magnetize the disk. Degaussing is De-magnetizing the disk, I suppose.

Online
Last seen: 1 hour 36 min ago
Joined: Dec 20 2003 - 10:38
Posts: 503
Re: Get rid of errors on your floppy disks. FIX THEM!

Maybe I was doing it wrong but I never was able to erase a disk with a magnet. I mad some on a speaker and they kept working, I stuck one to my fridge with a really strong magnet for a year and it still worked.
Accidentally leaving one om an Apple Graphic tablet did did it though I had't wanted to wipe that particular disk.

amauget's picture
Offline
Last seen: 3 hours 39 min ago
Joined: Jan 3 2011 - 11:34
Posts: 331
Re: Get rid of errors on your floppy disks. FIX THEM!

In my comprehension, the magnet was supposed to generate mangetic fields, enemies of the disk.

Offline
Last seen: 1 month 5 days ago
Joined: Apr 24 2012 - 17:03
Posts: 268
Re: Get rid of errors on your floppy disks. FIX THEM!

Some time ago I bought a lot of used apple disks with programs. They gave me errors and sometimes didn't load at all. My solution was cleaning the disks - put some alcohol on a rag, and move the disk while leaving the rag on the disk opening. The white rag went grey with dirt. Did that to all disks on both sides, they started working again.
Cheers

Javster

Offline
Last seen: 2 weeks 3 days ago
Joined: May 27 2013 - 13:01
Posts: 825
Re: Get rid of errors on your floppy disks. FIX THEM!

The bulk tape eraser is an electromagnet. Using the process I described, as you keep the eraser on and near the disk it will become magnetized. But when you move the eraser away from the disk while keeping it on it demagnetizes the disk.

In watchmaking, (the last trade I was officially part of) there are instances where demagnetizing a mechanical watch was required for either demagnetizing the hairspring (balance spring) or to demagnetize the entire watch to remove magnetism on the watch which can create problems in accuracy.

Offline
Last seen: 1 week 5 days ago
Joined: Apr 20 2013 - 21:20
Posts: 64
Re: Get rid of errors on your floppy disks. FIX THEM!

The Bulk tape eraser used an alternating current/voltage and hence magnetic field, the way it is meant to be used is to start the demagnetization close to the disk/tape and slowly move it away. I was taught to also move the eraser in circles as you do this, the complete process should only take 30 seconds or less.

A magnet can work but as its a fixed polarity you run the risk of magnetizing the disk/tape with the same polarity as the end of the magnet you are using. From experience a magnet can work to erase the data but you run the risk of permanently magnetizing the disk so that it can't be written to or formatted unless a bulk eraser is used afterwards.

Cheers, Martin...

Offline
Last seen: 2 weeks 3 days ago
Joined: May 27 2013 - 13:01
Posts: 825
Re: Get rid of errors on your floppy disks. FIX THEM!

The Bulk tape eraser used an alternating current/voltage and hence magnetic field, the way it is meant to be used is to start the demagnetization close to the disk/tape and slowly move it away. I was taught to also move the eraser in circles as you do this, the complete process should only take 30 seconds or less.

A magnet can work but as its a fixed polarity you run the risk of magnetizing the disk/tape with the same polarity as the end of the magnet you are using. From experience a magnet can work to erase the data but you run the risk of permanently magnetizing the disk so that it can't be written to or formatted unless a bulk eraser is used afterwards.

Cheers, Martin...

There's nothing in your post which I have not already mentioned already but thanks for the help. Smile

Offline
Last seen: 8 months 2 weeks ago
Joined: Jun 21 2012 - 21:40
Posts: 66
Re: Get rid of errors on your floppy disks. FIX THEM!

By gradually moving the disc away from the VERY STRONG AC magnetic field of the degausser, you are overcoming the natural hysteresis loop of the magnetic particles themselves, which in an every decreasing loop insures that every particle is zeroed out, no information will remain there. Erased, permanently! No program or forensic technique can recover ANY usable charges from a properly demagnetized tape or disc.

Offline
Last seen: 10 months 4 weeks ago
Joined: Dec 13 2005 - 08:40
Posts: 265
Re: Get rid of errors on your floppy disks. FIX THEM!

Sometimes the disk are worn out, or have manufacturing defect, or even a physical defect from a pointed object. When you look at them you can actually see the separate tracks in some spots. They were read over and over in some areas. When you manually move the media around in a circle you can sometimes see a spot like what a grain sand looks like when it flaws a paint job. And last but not least someone stabbed the disk with a pencil or pen.

Offline
Last seen: 2 weeks 3 days ago
Joined: May 27 2013 - 13:01
Posts: 825
Re: Get rid of errors on your floppy disks. FIX THEM!

the way it is meant to be used is to start the demagnetization close to the disk/tape and slowly move it away. I was taught to also move the eraser in circles as you do this, the complete process should only take 30 seconds or less.

I already said this...

To Degauss your floppy disk, hold it in your hand and turn on the tape eraser and make a circular motion for a few seconds, then while keeping it on, move the tape eraser away from the floppy and then turn it off.

By gradually moving the disc away from the VERY STRONG AC magnetic field of the degausser, you are overcoming the natural hysteresis loop of the magnetic particles themselves, which in an every decreasing loop insures that every particle is zeroed out, no information will remain there. Erased, permanently! No program or forensic technique can recover ANY usable charges from a properly demagnetized tape or disc.

Does everybody in this forum have some kind of repeating problem? Is there an echo in here?

Here is what I said:

A COMPLETE ERASE.

Also known as Degaussing, it will permanently erase a disk and bring it to a state of no format.

People are just repeating what I posted.

This is a thread about fixing disks that cannot be formatted without errors. It is not about data recovery.

We make sure we have data by backing it up.

If there are errors on a disk with data on it then trying to format the disk will also destroy data on it wouldn't you say?

Here was my introduction:

Here's a little trick that I have been using since the old days...

Ever encounter a floppy disk that keeps giving you an error in the same sector no matter how many times you format it?

Offline
Last seen: 3 years 7 months ago
Joined: Nov 2 2018 - 13:54
Posts: 1
insanitor wrote:mnc1959 wrote

[quote=insanitor][quote=mnc1959]The Bulk tape eraser used an alternating current/voltage and hence magnetic field, the way it is meant to be used is to start the demagnetization close to the disk/tape and slowly move it away. I was taught to also move the eraser in circles as you do this, the complete process should only take 30 seconds or less. [/quote] There's nothing in your post which I have not already mentioned already but thanks for the help. :)[/quote]

 

You didn't mention AC current. Mnc1959 helps us understand how bulk eraser removes the magnetic field and why normal magnet or DC electromagnet doesn't work.

Offline
Last seen: 3 months 1 week ago
Joined: Mar 18 2022 - 15:31
Posts: 1
I can confirm, a STRONG permanent magnet works for me

Old thread, new post... but I am dabbling a bit with retro-PC restoration and ran into the same question about floppy disks. I can confirm, erasing the 3.5" floppy by holding a strong Neodymium magnet up to the case, and then spinning the floppy insert with a screwdriver, fixed all of the formatting problems for me.

 

So it was a magnetization defect (reversible), not a physical defect (permanent), that caused the formatting errors.

 

Here's how I became suspicious about the nature of the disk formatting errors:

 

Starting with a blank, not formatted, freshly bought (on Ebay) 3.5" HD floppy disk:

1st pass:  Formatting in computer A: no errors

2nd pass: Formatting in computer B: some errors (2,048 bytes in bad clusters)

3rd pass: Formatting in computer A:  even more errors (more bad clusters)

 

.. that's strange. I inspected the floppy surface by opening the slider, but could not see any visible scratch marks or defects.

 

At this point I erased the entire floppy with the NdFeB magnet, which has around >3000 Gauss at its surface. The 3.5" HD floppy coercivity is around 660 Gauss, so accounting for the magnetic field being a little weaker a short distance away from the magnet, I feel confident that such a magnet, held against the outside of the floppy, will erase the magnetic film directly under it.

 

Now I got:

 

4th pass: Formatting in computer A: no errors

5th pass: Formatting in computer B: no errors

6th pass: Formatting in computer B: no errors

7th pass: Formatting in computer A: no errors

 

So yes, it would appear that magnetically erasing a 3.5" HD floppy with a strong DC (permanent) magnet can restore the floppy to full, error-free functionality.

 

The main message here is, YOU PROBABLY DON'T HAVE TO BUY AN EXPENSIVE AC DEGAUSSER  - a simple, strong magnet might do the trick.

 

I will be shortly trying this with some other floppies that had formatting errors but no visible defects. I will also try to actually write files to the floppy, but in my understanding, the normal "slow" format (not quick format) already does a read/write verification of the entire floppy surface.

 

Finally, I agree that a DC magnet will probably leave some DC magnetization on the floppy disk, more so than a nice AC degausser. However, the floppy read head is an inductive read head, meaning it detects only magnetic transitions, and it does not detect the DC component of the magnetic medium. So effectively, the floppy read head will - probably - be largely insensitive to any residual DC bias in the magnetic film. Only the very compactly spaced magnetic transitions written by the floppy write head will be detected by the inductive read head.

 

So as long as the floppy write head can locally overwrite the DC magnetization from the permanent magnet, all should be fine.

 

P.S. How can you tell if you are formatting a blank floppy, or re-formatting a previously formatted disk? When formatting begins, the floppy disk drive tries to read the innermost track first. If that succeeds, the format will commence immediately. However, when reading the innermost track fails (e.g. blank or magnetically fully erased disk), then the floppy drive will re-attempt reading the inner track several times, before formatting the disk. So the extra delay and extra buzzing at the beginning of a full format is the tell-tale that the disk was truly blank.

 

 

 

 

 

 

 

 

Offline
Last seen: 3 hours 32 min ago
Joined: Feb 27 2021 - 18:59
Posts: 173
Part of the problem is that

Part of the problem is that "format" doesn't have a universally accepted meaning.

A magnetic medium like a floppy diskette needs to have a way for the drive to locate the locations of each storage block or sector, so it can read or write at the correct time and place to update the contents. The way this is usually accomplished is to have a block header before each sector that marks the precise place that sector begins and identifies it by number. The procedure for writing all the headers to the disk is called "formatting" because it impresses a specific format (number and location of sectors) on a blank and unstructured medium. Some of the choices that can be made during formatting include the sector interleave and slip. When a disk is read and written during normal operation, the headers are never rewritten: you can update the sector contents many times but the headers created during formatting stay the same. So on an old disk, the magnetic patterns of the headers may be weak or scrambled and this causes problems finding the correct place to read/write the data.

However, to many computer users and some companies, "format" refers to "preparing a disk", and this is where the confusion sets in, because to actually store files on a disk something else needs to be done: writing the director(y|ies) and allocation tables to tell the OS where the files are. But this initialization step has nothing to do with formatting as described above. You can re-initialize a disk (write over its file tables) without recreating the format/headers. Some types of disk (such as magneto-optical) cannot be re-formatted because the sector headers are permanently pressed at the factory, but they can be re-initialized. Many hard disks also are never re-formatted, but only re-initialized when you decide to erase them (so-called "low-level format" commands may be implemented but they are not always easily accessed).

Your reference to "clusters" is related to the higher-level initialization procedure. A cluster is a unit of allocation that is associated with a file in a file allocation table (different from a sector which is a physical block located with a sector header). When the machine prepares a disk, it needs to prevent files being stored over surface defects, since data could be lost, so clusters containing defects are marked in a table as unavailable to hold file data.

If a degausser is used to erase a disk, it removes both the sector headers and data, so a low-level format is needed before the disk can be initialized. Both steps (format, initialize) can be performed by the same program, but there is often a switch to determine which (or both) should be done.

Log in or register to post comments