Getting Data off old Atari Floppies
One thing I really don't like about old floppies is that for certain brands etc of 5.25" floppies (and possibly 8" floppies) the media turns to mush and will get all over the drive heads (and destroy the disk)
My experience is, the magnetic coating crumbles. Friction turns the fragments into what might be called "mush". I confirm bad experiences cited with "Wabash" branded 5.25" diskettes.
Supposedly (Based on info from Chuck Guzis/sydex, though I've never tried this myself), if you dismantle the floppy by cutting open the vinyl case and removing the "cookie" inside, and put it on a baking sheet and bake it in the oven at 300F(?) for maybe 8 hours, they can be made readable again. You may need to apply some sort of sealant to the outside of the disk after baking.
This is, to be polite, flawed advice. There may be some confusion about "baking" 1/4" audio magnetic tapes - I have no details about that process. The diskette Mylar cookie will distort with heat - period. So will the plastic envelope. Distortion temperatures are likely above, 120, 130 degrees F. I don't know the minimum. Storage above room temperature is not recommended. I won't say "try this to see" because someone will mess up their oven and blame me. If you try this, use all possible caution and do NOT leave your experiment unattended. I am not responsible for injury or damage to you, your oven, and certainly to your diskette. My previous post in this thread, has a link to a Web page on my site, which discusses recovery methods I'm aware of. Herb -- Herbert R. Johnson, New Jersey USA http://www.retrotechnology.com OR .net
On Mon, Dec 14, 2015 at 1:47 PM, Herb Johnson via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Supposedly (Based on info from Chuck Guzis/sydex, though I've never tried this myself), if you dismantle the floppy by cutting open the vinyl case and removing the "cookie" inside, and put it on a baking sheet and bake it in the oven at 300F(?) for maybe 8 hours, they can be made readable again. You may need to apply some sort of sealant to the outside of the disk after baking.
This is, to be polite, flawed advice. There may be some confusion about "baking" 1/4" audio magnetic tapes - I have no details about that process.
The diskette Mylar cookie will distort with heat - period. So will the plastic envelope. Distortion temperatures are likely above, 120, 130 degrees F. I don't know the minimum. Storage above room temperature is not recommended.
I thought 300 degrees F is a bit high, personally, but looking at DuPont's datasheet for Mylar, it looks to me like it can quite easily handle it. It has a melting point of 489 degrees F, after all. The shrinkage specs also look quite respectable; it looks like you can expect 2% shrinkage at 300 degrees F. That being said, most procedures I see for baking tapes rely on 130 degrees F. http://audio-restoration.com/baking.php for instance, cites 130 degrees F as being a good target temperature. Regarding the envelope: he did say to cut open the "vinyl case" and remove the cookie. Might be worth a try on those nasty Wabash disks. Kyle
On Dec 14, 2015, at 14:56, Kyle Owen via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
On Mon, Dec 14, 2015 at 1:47 PM, Herb Johnson via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Supposedly (Based on info from Chuck Guzis/sydex, though I've never tried this myself), if you dismantle the floppy by cutting open the vinyl case and removing the "cookie" inside, and put it on a baking sheet and bake it in the oven at 300F(?) for maybe 8 hours, they can be made readable again. You may need to apply some sort of sealant to the outside of the disk after baking.
This is, to be polite, flawed advice. There may be some confusion about "baking" 1/4" audio magnetic tapes - I have no details about that process.
The diskette Mylar cookie will distort with heat - period. So will the plastic envelope. Distortion temperatures are likely above, 120, 130 degrees F. I don't know the minimum. Storage above room temperature is not recommended.
I thought 300 degrees F is a bit high, personally, but looking at DuPont's datasheet for Mylar, it looks to me like it can quite easily handle it. It has a melting point of 489 degrees F, after all. The shrinkage specs also look quite respectable; it looks like you can expect 2% shrinkage at 300 degrees F.
That being said, most procedures I see for baking tapes rely on 130 degrees F. http://audio-restoration.com/baking.php for instance, cites 130 degrees F as being a good target temperature.
Regarding the envelope: he did say to cut open the "vinyl case" and remove the cookie.
Might be worth a try on those nasty Wabash disks.
Chuck's advice was to do what he did: make a plywood box, put a 25W bulb in, and "bake" it in there for a few days (sans vinyl jacket). That won't get you above warping temperature. Please don't bake any plastic-based media at 300F. - Dave
On 12/14/2015 6:50 PM, David Riley via vcf-midatlantic wrote:
On Dec 14, 2015, at 14:56, Kyle Owen via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
On Mon, Dec 14, 2015 at 1:47 PM, Herb Johnson via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Supposedly (Based on info from Chuck Guzis/sydex, though I've never tried this myself), if you dismantle the floppy by cutting open the vinyl case and removing the "cookie" inside, and put it on a baking sheet and bake it in the oven at 300F(?) for maybe 8 hours, they can be made readable again. You may need to apply some sort of sealant to the outside of the disk after baking. This is, to be polite, flawed advice. There may be some confusion about "baking" 1/4" audio magnetic tapes - I have no details about that process.
The diskette Mylar cookie will distort with heat - period. So will the plastic envelope. Distortion temperatures are likely above, 120, 130 degrees F. I don't know the minimum. Storage above room temperature is not recommended. I thought 300 degrees F is a bit high, personally, but looking at DuPont's datasheet for Mylar, it looks to me like it can quite easily handle it. It has a melting point of 489 degrees F, after all. The shrinkage specs also look quite respectable; it looks like you can expect 2% shrinkage at 300 degrees F.
That being said, most procedures I see for baking tapes rely on 130 degrees F. http://audio-restoration.com/baking.php for instance, cites 130 degrees F as being a good target temperature.
Regarding the envelope: he did say to cut open the "vinyl case" and remove the cookie.
Might be worth a try on those nasty Wabash disks. Chuck's advice was to do what he did: make a plywood box, put a 25W bulb in, and "bake" it in there for a few days (sans vinyl jacket). That won't get you above warping temperature. Please don't bake any plastic-based media at 300F.
- Dave
Yeah 300F was completely wrong, I was mixing baking floppies up with baking EPROMS after x-ray (not UV!) based erasure (which really does need 300F). -- Jonathan Gevaryahu jgevaryahu@gmail.com jgevaryahu@hotmail.com
On 12/14/2015 07:11 PM, Jonathan Gevaryahu via vcf-midatlantic wrote:
Yeah 300F was completely wrong, I was mixing baking floppies up with baking EPROMS after x-ray (not UV!) based erasure (which really does need 300F).
Can you tell me more about this? Does baking somehow address the problem of surface state creation during X-ray erasure? (I type this with a glance at a stack of trays containing several thousand non-windowed EPROM-based microcontrollers, and another glance over at my X-ray machine..) -Dave -- Dave McGuire, AK4HZ New Kensington, PA
On 12/14/2015 7:14 PM, Dave McGuire via vcf-midatlantic wrote:
On 12/14/2015 07:11 PM, Jonathan Gevaryahu via vcf-midatlantic wrote:
Yeah 300F was completely wrong, I was mixing baking floppies up with baking EPROMS after x-ray (not UV!) based erasure (which really does need 300F). Can you tell me more about this? Does baking somehow address the problem of surface state creation during X-ray erasure?
(I type this with a glance at a stack of trays containing several thousand non-windowed EPROM-based microcontrollers, and another glance over at my X-ray machine..)
-Dave
All I can tell you about this is what I read from wikipedia's "EPROM" article and some articles on history of EPROM/intel 1702 stuff: " Erasure can also be accomplished with X-rays <https://en.wikipedia.org/wiki/X-ray>: Erasure, however, has to be accomplished by non-electrical methods, since the gate electrode is not accessible electrically. Shining ultraviolet light on any part of an unpackaged device causes a photocurrent to flow from the floating gate back to the silicon substrate, thereby discharging the gate to its initial, uncharged condition (photoelectric effect <https://en.wikipedia.org/wiki/Photoelectric_effect>). This method of erasure allows complete testing and correction of a complex memory array before the package is finally sealed. Once the package is sealed, information can still be erased by exposing it to X radiation in excess of 5*10^4 rads <https://en.wikipedia.org/wiki/Rad_%28unit%29>,^[a] <https://en.wikipedia.org/wiki/EPROM#cite_note-6> a dose which is easily attained with commercial X-ray generators.^[6] <https://en.wikipedia.org/wiki/EPROM#cite_note-7> In other words, to erase your EPROM, you would first have to X-ray it and then put it in an oven at about 600 degrees Celsius (to anneal semiconductor alterations caused by the X-rays). The effects of this process on the reliability of the part would have required extensive testing so they decided on the window instead.^[7] <https://en.wikipedia.org/wiki/EPROM#cite_note-jmargolin_com-eprom-8> " Also, 600C(1100F) is a fair bit higher than what I remembered from last time I read this. Maybe try it with one less-desirable microcontroller and the X-ray generator? And bake it at various temperatures and see if it 'recovers'? -- Jonathan Gevaryahu jgevaryahu@gmail.com jgevaryahu@hotmail.com
On Mon, 14 Dec 2015, Dave McGuire via vcf-midatlantic wrote:
On 12/14/2015 07:11 PM, Jonathan Gevaryahu via vcf-midatlantic wrote:
Yeah 300F was completely wrong, I was mixing baking floppies up with baking EPROMS after x-ray (not UV!) based erasure (which really does need 300F).
Can you tell me more about this? Does baking somehow address the problem of surface state creation during X-ray erasure?
(I type this with a glance at a stack of trays containing several thousand non-windowed EPROM-based microcontrollers, and another glance over at my X-ray machine..)
-Dave
You forgot to mention your electron microscope. Mike Loewen mloewen@cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/
On 12/14/2015 07:41 PM, Mike Loewen via vcf-midatlantic wrote:
Yeah 300F was completely wrong, I was mixing baking floppies up with baking EPROMS after x-ray (not UV!) based erasure (which really does need 300F).
Can you tell me more about this? Does baking somehow address the problem of surface state creation during X-ray erasure?
(I type this with a glance at a stack of trays containing several thousand non-windowed EPROM-based microcontrollers, and another glance over at my X-ray machine..)
You forgot to mention your electron microscope.
Can an electron beam erase EPROMs nondestructively?? -Dave -- Dave McGuire, AK4HZ New Kensington, PA
On 12/14/2015 7:43 PM, Dave McGuire via vcf-midatlantic wrote:
On 12/14/2015 07:41 PM, Mike Loewen via vcf-midatlantic wrote:
Yeah 300F was completely wrong, I was mixing baking floppies up with baking EPROMS after x-ray (not UV!) based erasure (which really does need 300F). Can you tell me more about this? Does baking somehow address the problem of surface state creation during X-ray erasure?
(I type this with a glance at a stack of trays containing several thousand non-windowed EPROM-based microcontrollers, and another glance over at my X-ray machine..) You forgot to mention your electron microscope. Can an electron beam erase EPROMs nondestructively??
-Dave
I know a UV laser can, but you need to live-decap (i.e. decap without damaging the die or bond wires) the chip first. This is used by security researchers to unset security bits etc on microcontrollers. -- Jonathan Gevaryahu jgevaryahu@gmail.com jgevaryahu@hotmail.com
On 12/14/2015 07:46 PM, Jonathan Gevaryahu via vcf-midatlantic wrote:
Yeah 300F was completely wrong, I was mixing baking floppies up with baking EPROMS after x-ray (not UV!) based erasure (which really does need 300F). Can you tell me more about this? Does baking somehow address the problem of surface state creation during X-ray erasure?
(I type this with a glance at a stack of trays containing several thousand non-windowed EPROM-based microcontrollers, and another glance over at my X-ray machine..) You forgot to mention your electron microscope. Can an electron beam erase EPROMs nondestructively??
I know a UV laser can, but you need to live-decap (i.e. decap without damaging the die or bond wires) the chip first. This is used by security researchers to unset security bits etc on microcontrollers.
Well we know UV can. That's just targeted UV. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
On 12/14/2015 7:47 PM, Dave McGuire via vcf-midatlantic wrote:
On 12/14/2015 07:46 PM, Jonathan Gevaryahu via vcf-midatlantic wrote:
Yeah 300F was completely wrong, I was mixing baking floppies up with baking EPROMS after x-ray (not UV!) based erasure (which really does need 300F). Can you tell me more about this? Does baking somehow address the problem of surface state creation during X-ray erasure?
(I type this with a glance at a stack of trays containing several thousand non-windowed EPROM-based microcontrollers, and another glance over at my X-ray machine..) You forgot to mention your electron microscope. Can an electron beam erase EPROMs nondestructively?? I know a UV laser can, but you need to live-decap (i.e. decap without damaging the die or bond wires) the chip first. This is used by security researchers to unset security bits etc on microcontrollers. Well we know UV can. That's just targeted UV.
-Dave
I don't have access to an X-ray source here, so I've never tried it. -- Jonathan Gevaryahu jgevaryahu@gmail.com jgevaryahu@hotmail.com
On 12/14/2015 2:47 PM, Herb Johnson via vcf-midatlantic wrote:
This is, to be polite, flawed advice. There may be some confusion about "baking" 1/4" audio magnetic tapes - I have no details about that process.
The diskette Mylar cookie will distort with heat - period. So will the plastic envelope. Distortion temperatures are likely above, 120, 130 degrees F. I don't know the minimum. Storage above room temperature is not recommended.
You definitely do not want to bake the vinyl case portion of the floppy. I may have the baking temperature completely wrong (perhaps it really is only 110-120F?) for the 'cookie'/media part. I believe it should be baked against a flat (polished?) metal surface to prevent distortion, but again I could be completely wrong. (I suppose it could melt like an egg even if it is against a flat surface)
I won't say "try this to see" because someone will mess up their oven and blame me. If you try this, use all possible caution and do NOT leave your experiment unattended. I am not responsible for injury or damage to you, your oven, and certainly to your diskette. I've got some already damaged wabash disks which might be worth experimenting on...
My previous post in this thread, has a link to a Web page on my site, which discusses recovery methods I'm aware of.
I'll check it out.
Herb
-- Jonathan Gevaryahu jgevaryahu@gmail.com jgevaryahu@hotmail.com
You definitely do not want to bake the vinyl case portion of the floppy. I may have the baking temperature completely wrong (perhaps it really is only 110-120F?) for the 'cookie'/media part. I believe it should be baked against a flat (polished?) metal surface to prevent distortion, but again I could be completely wrong. (I suppose it could melt like an egg even if it is against a flat surface)
Baking tapes is done to remove moisture. Why not just throw the disks in with some dessicant (Damp rid comes to mind?) I bought some damp rid in preperation for reducing moisture in some umatic tapes that have laser show data digitally encoded. But so far the tapes play really well and I just dump the converted signals to HD based ADAT machine. Beta tapes faired poorly.
participants (7)
-
Dave McGuire -
David Riley -
Ethan -
Herb Johnson -
Jonathan Gevaryahu -
Kyle Owen -
Mike Loewen