Bulk erase methods

[Al]

The frequency is irrelevant. The point is to have a strong enough
magnetic field to line up all of the little magnetic thingies in
the media, and then turn them all around on the next half-cycle.

A permanent magnet will line up all the little thingies, but then
you've got a magnet bias that could introduce confounding factors
when re-using the media.

Anyway, with the AC field (hey, there's a usage of AC that we
didn't consider in the "Tastes Great-Less Filling" ACDC thing!),
just twirl the magnet fast enough that it can sweep the field
over the media once or twice.

Then, the secret is, slowly move the moving magnet ( or half
a transformer, or whatever) away from the media, and as the
alternating field gets weaker and weaker, reversing fewer
and fewer thingies, until on the average, there's no
residual magnetism in the media.

It's the same principle with CRT degaussers, but they use
a PTC thermistor in series with the coil. Press the degausser
button on your monitor - see the pretty patterns? And how
they decay? That's the principle that ends up with
negligible residual magnetization. I know there's a whole
nother jargon here, but, come on!

Anyway, Hope This Helps!

Cheers!
Rich

Years ago, bulk magnetic tape erasers were sold for erasing reel-to-reel
magnetic tapes. You might be able to find one in an antiques store ;-)
and use it for your purpose.

Al

 

[Keith Williams]

Years ago, bulk magnetic tape erasers were sold for erasing reel-to-reel
magnetic tapes. You might be able to find one in an antiques store ;-)
and use it for your purpose.

Digital media, floppys in particular, have a much higher coercivity
than reel-to-reek audio tape, so don't expect the "bulk eraser" to work
very well. A shredder is a far better method. If the floppys are to
be reused, formatting them will deter all but the black-hats.

 

[[email protected]]

very well. A shredder is a far better method. If the floppys are to

be reused, formatting them will deter all but the black-hats.

You'd be surprised how easy it is to recover data from a floppy that
has only been formatted. All you need is a scope and patience. The
azimuth variations between any two drives make the "lost" data readable
easily on another drive.

 

[Keith Williams]

You'd be surprised how easy it is to recover data from a floppy that
has only been formatted. All you need is a scope and patience. The
azimuth variations between any two drives make the "lost" data readable
easily on another drive.

If the data is that sensitive, shred the things. In fact, shred them
anyway. Floppys are dead. ;-)

 

[Jim Thompson]

You'd be surprised how easy it is to recover data from a floppy that
has only been formatted. All you need is a scope and patience. The
azimuth variations between any two drives make the "lost" data readable
easily on another drive.

I've been lurking at this thread for awhile...

If the OP meant that bulk erase was needed to render the floppies
disposable with security, then mechanical destruction is certainly the
only reliable way.

If the OP only wanted to re-use the floppies himself, what's wrong
with simply "delete *.*" ??

If he meant to distribute erased floppies for others to re-use, but
with security, there exists software which will write randomized data
over the existing data.

...Jim Thompson

 

[Keith Williams]

I've been lurking at this thread for awhile...

If the OP meant that bulk erase was needed to render the floppies
disposable with security, then mechanical destruction is certainly the
only reliable way.

Yep. Riaisng the temperature above the curie point works too, but that
likely amounts to the same thing.

If the OP only wanted to re-use the floppies himself, what's wrong
with simply "delete *.*" ??

That simply clears the directory. The files are still there.

If he meant to distribute erased floppies for others to re-use, but
with security, there exists software which will write randomized data
over the existing data.

The new data won't cover the old data completely, unless it was written
by the same drive (and it hasn't changed calibration). If any security
is required, go back to solution #1.

 

[John Larkin]

I've been lurking at this thread for awhile...

If the OP meant that bulk erase was needed to render the floppies
disposable with security, then mechanical destruction is certainly the
only reliable way.

If the OP only wanted to re-use the floppies himself, what's wrong
with simply "delete *.*" ??

If he meant to distribute erased floppies for others to re-use, but
with security, there exists software which will write randomized data
over the existing data.

...Jim Thompson

Why not just reformat? Even the CIA would have to be lucky to recover
any data after that.

John

 

[Jim Thompson]

On Thu, 14 Jul 2005 08:13:49 -0700, Jim Thompson
[snip]

I've been lurking at this thread for awhile...

If the OP meant that bulk erase was needed to render the floppies
disposable with security, then mechanical destruction is certainly the
only reliable way.

If the OP only wanted to re-use the floppies himself, what's wrong
with simply "delete *.*" ??

If he meant to distribute erased floppies for others to re-use, but
with security, there exists software which will write randomized data
over the existing data.

...Jim Thompson

Why not just reformat? Even the CIA would have to be lucky to recover
any data after that.

John

Another poster claimed that they could get data even from a
reformatted disk.

Maybe, but I doubt it myself.

...Jim Thompson

 

[GregS]

I still sometimes have to erase a floppy to use it, if the format
is not recognized by the computer. A standard hand held bulk eraser
is what I use. Still a somewhat time consuming process, as
it takes several passes to do it. Is there still such a thing being sold?
Ebay?

Using the computer to erase is obviously a very long chore.

greg

 

[Guy Macon]

I still sometimes have to erase a floppy to use it, if the format
is not recognized by the computer.

I use floppies in my PC, my CP/M system and my Commodore.
Without a bulk erase, you get many, many errors.

A standard hand held bulk eraser is what I use.

The ones for cassette tapes are a bit weak. The Radio
Shack videotape eraser is quite strong and very low priced.

Still a somewhat time consuming process, as it takes several passes
to do it.

Hold the eraser and the floppy as far away from each other
as your arms will reach. Turn on eraser. Bring them together,
taking at least 5 seconds to do so. Do one circular pass on
each side. Bring them arms-length apart again. Turn of the
eraser. Always move slowly, never more than one foot per second,
and never turn the eraser on or off while near the target.

Is there still such a thing being sold?

Radio Shack. Videotape eraser. Works great. Cheap.

Also fun with CRT monitors (but *NOT* Trinitrons!
You can actually tangle the shadow mask wires!)

Even more fun with metal surfaces such as filing cabinets.
Makes a loud noise that is perfect for that special moment
when someone powers up newly built or repaired electronics.

 

[[email protected]]

Why not just reformat? Even the CIA would have to be lucky to recover

Another poster claimed that they could get data even from a
reformatted disk.

If it's only been reformatted once, then it's not very difficult to
recover the data. I've had this demonstrated to me briefly.

 

[[email protected]]

If the data is that sensitive, shred the things. In fact, shred them
anyway. Floppys are dead. ;-)

That's exactly what I said much earlier in the thread

 

[[email protected]]

I've been lurking at this thread for awhile...

If the OP meant that bulk erase was needed to render the floppies
disposable with security, then mechanical destruction is certainly the
only reliable way.

If the OP only wanted to re-use the floppies himself, what's wrong
with simply "delete *.*" ??

If he meant to distribute erased floppies for others to re-use, but
with security, there exists software which will write randomized data
over the existing data.

thanks Jim. Theyre for reuse by other people, floppies are not obsolete
yet. High security is not needed, but the info does need to be all
truly deleted rather than simply delete *.* which leaves it all on
there. And finally, putting loads of floppies thru a PC and writing
them one by one is not worth it, I want fast bulk erase and no cost.
There are a lot to wipe, PCing them individually isnt even worth
considering.

I'll try this actuator magnet later, and also the microwave.


Thanks, NT

 

[Keith Williams]

thanks Jim. Theyre for reuse by other people, floppies are not obsolete
yet. High security is not needed, but the info does need to be all
truly deleted rather than simply delete *.* which leaves it all on
there. And finally, putting loads of floppies thru a PC and writing
them one by one is not worth it, I want fast bulk erase and no cost.
There are a lot to wipe, PCing them individually isnt even worth
considering.

They have to be formatted after a bulk erase anyway. You're just
moving the time needed for the format to the point at which they're
needed (and perhaps needed *now*), rather than when one is doing
something else and can feed the drive.

I'll try this actuator magnet later, and also the microwave.

DOn't count on them (perhaps including the microwave) being useful
after the nuking. ....particularly 3-1/2" floppies.

 

[Jim Thompson]

They have to be formatted after a bulk erase anyway. You're just
moving the time needed for the format to the point at which they're
needed (and perhaps needed *now*), rather than when one is doing
something else and can feed the drive.

DOn't count on them (perhaps including the microwave) being useful
after the nuking. ....particularly 3-1/2" floppies.

Sheeesh! Floppies are CHEAP. Just destroy the originals and BUY new.

...Jim Thompson

 

[Keith Williams]

Sheeesh! Floppies are CHEAP. Just destroy the originals and BUY new.

Destroy the floppies and buy a USB stick and/or CD R/W drive. ;-)

I've only used floppies once in the last two years; to flash BIOS. I
didn't want to figure out how to do it from the HD.

 

[[email protected]]

Destroy the floppies and buy a USB stick and/or CD R/W drive. ;-)

would achieve precisely none of the aims here. It wont be me that
reuses the flops.

And why buy USB stick when you can use a HDD for more capacity at lower
price?

NT

 

[Zak]

would achieve precisely none of the aims here. It wont be me that
reuses the flops.

Really erasing is hard. In teh past I'bve purchased 'recycled' flops
from software packages. Some were readable, some partially. Got me a
nearly free copy of Lotus 1-2-3

You could try a degausser coil from a TV picture tube. Be careful as it
runs on line voltage.

You could try 'improving' it by folding it to have more turns... all
turns obviously in teh same direction. This should be a 5 second job.


Thomas

 

[Keith Williams]

would achieve precisely none of the aims here. It wont be me that
reuses the flops.

If you have any concerns about security, don't. Shred them.

And why buy USB stick when you can use a HDD for more capacity at lower
price?

Portability? Why else would one use a floppy? I carry a USB stick on my
key ring. I don't think I want to carry a HDD in such a manner.

 

[[email protected]]

[email protected] wrote:

Really erasing is hard. In teh past I'bve purchased 'recycled' flops
from software packages. Some were readable, some partially. Got me a
nearly free copy of Lotus 1-2-3

You could try a degausser coil from a TV picture tube. Be careful as it
runs on line voltage.

You could try 'improving' it by folding it to have more turns... all
turns obviously in teh same direction. This should be a 5 second job.

I tried that in the days of cassettes, but it didnt work. Made the bit
of metal rattle, but nothing got erased. Professional tape degaussers
are beasts compared to a tv degauss coil.


NT