Re: The Diskette Experiments

[mjmahon@aol.com (Michael J. Mahon)]

Paul Allen Panks wrote:

>"The Diskette Experiments: A Hypothetical Longevity of the Floppy Disk"
>By: Paul Allen Panks (dunric@yahoo.com)
>
>See website for details. Written summary below:
>
>http://members.tripod.com/~panks/diskfun.html

<snip>

>*************************************************************
>Experiment One: Freezing diskette (Conducted in January 2003)
>*************************************************************
>Hypothesis: Frozen diskettes lose data, even if frozen overnight.
...
>Conclusion: Freezing a diskette overnight probably won't damage the
>diskette enough to ruin diskette data integrity, but probably isn't a
>good idea, anyway.

Lowering the temperature of magnetic media should only serve
to prolong the life of the magnetic domains, as long as mechanical
damage (e.g.: oxide separation) does not occur.

>*************************************************************
>Experiment Two: Overheating diskette (Conducted in June 2004)
>*************************************************************
>
>Hypothesis: Heating a diskette to even slightly above room temperature
>is asking for data loss.
...
>Conclusion: Heating a 96 TPI (HD) 5.25" diskette (or 48 TPI diskette)
>to 95-115 degrees fahrenheit does not appear to affect data integrity
>in any significant fashion, although outright *burning* of the
>diskette *will* affect data integrity!

Raising the temperature of magnetic media will decrease the
lifetime of magnetic domains, but not significantly unless the
Curie temperature for the media is exceeded.  For diskettes,
this temperature is in excess of the melting point of the carrier.
So, as with cooling, as long as mechanical integrity is preserved,
the data should survive.  However, long-term storage at elevated
temperatures will hasten the normal deterioration of the magnetic
domains.

>********************************************************************
>Experiment Three: Diskette burial for 554 days (March 2003-Oct 2004)
>********************************************************************
>
>Hypothesis: Burying a diskette for over a period of a year,
>approximately 1.5 feet underground, will expose the diskette to dirt,
>rain and other unsavory elements, even when contained within a
>ZipLock(TM) plastic bag.
...
>Conclusion: Burying a diskette even 18 inches below the ground for a
>period exceeding 1 calendar year, even when protected in a ZipLock(TM)
>sealed plastic bag, is generally *not* a good idea. Water (from rain)
>and other elements warped the physical nature of the diskette, as did
>the 18 inches of dirt laying atop the diskette (inside a sealed
>ZipLock(TM) plastic bag). Even rescuing the internal mylar floppy from
>the disk jacket and transfering it into a fresh disk jacket failed to
>solve data loss. Physical damages to the diskette, although minimal to
>the eye, were nevertheless responsible for a total of at least 38
>programs (out of 45 total) either loading only 65-70% of the way,
>failing altogether (0%-2% of the way) or loading without error (only 5
>loaded without error, and the largest program of that variety was a
>mere 9 blocks in length).

Again, mechanical damage is the fundamental mechanism of
deterioration in this experiment.  Water should only be a problem
to the extent that it causes physical degradation of the oxide coating
or the binder, or that it supports biological activity that degrades them.

As the experimenter points out, physical damage or contamination
of the jacket is irrelevant if the actual disk can be placed in a clean
jacket for reading.  It is worthwhile to keep an "empty" jacket with
the top carefully cut open for such recovery operations.

The difficulty with doing "real" life testing of diskettes it that it
clearly requires several decades!

And even then, there is the problem of ascertaining the exact
characteristics of the recording drive and the specific media.

There is considerable evidence that some media are (were)
quite marginal in their properties, and that some were prone
to fungal infection, coating separation, oxide shedding, warping,
etc.  These specific physical defects seem to be a primary
cause of current diskette unreadability.

All of this must be separated from the cases of envirnmentally
accelerated deterioration in the magnetic recording resulting
from long-term high temperature storage (though this also
accelerates physical degradation) and exposure to magnetic
fields (say, being stored near a motor or a transformer).

I propose that there are relatively few examples of magnetic
deterioration, and the majority of reliability priblems are a
result of physical deterioration.  Further, in most cases of
magnetic deterioration, that the initial recording or the properties
of the media were marginal in most cases.

It would be interesting to do a larger scale experimental study
to determne the actual extent and nature of diskette degradation.

-michael

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