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Re: Rotting 5.25 floppies

winston19842005@yahoo.com wrote:

On Aug 5, 4:00 am, "Michael J. Mahon" <mjma...@aol.com> wrote:

winston19842...@yahoo.com wrote:

On Aug 4, 8:57 pm, bloomer_au <bloo...@iprimus.com.au> wrote:

Thanks for the advice guys.
To clarify one point:
"> Last night, after I played some Savage Island Part I, I put in a

different 5.25, and it did the screwing my drive routine.

I'm not sure exactly what you mean by this...  Do you mean that after
running this disk, disks that previously worked stop working? "
Yes, that is what I mean :) The Scott Adams disk ran fine multiple
times, but then I put this 2nd disk in. The 2nd disk wouldn't boot and
I got 'check startup device!', and then when I went back to the Scott
Adams disk, it wouldn't boot either. That suggested to me the
mechanism of the 2nd disk introducing some crud into the drive. I had
experienced this same pattern of trouble before with several 5.25s,
one standalone and a kind of duodisk thing (unsure of brand) attached
to an Apple II clone. So the pattern has been - disks work, then after
a particular disk is put in (not the exact same one mentioned in this
example) nothing works. Then after a clean or three, maybe I get to
the point where the first disk is okay to be run again. Or maybe
nothing ever works again. And my disks have been stored very well as
far as I can tell.

Ah, the "Disk of Death" syndrome. It has been documented, by me and a
few others.
After checking some disks that come out fine, put in another suspect
disk. It is unreadable.
Suddenly, you go through several more unreadable disks, then try a
previous disk, suspecting that something is wrong.
It no longer works.
The "suspect" disk "crudded" up your head. When you tried subsequent
disks, the "crud" basically sliced into the disk surface and messed
them up, including previous disks. Upon close inspection, I've
actually seen the disk surface marred after such an incident.
You may get the drive back by cleaning, you may not. I've gone through
several 3.5" drives on my PC because of going through "mystery" disks
that did exactly the above. The disks were ruined and I've lost at
least two drives that way. Probably wound up ruining the head by being
too rough during the cleaning process after a more mild attempt
failed.
A note about disk cleaners - I used to trust them, but the last time I
used one it ruined my last 3.5" drive (a new one I had just put in
after the previous one failed after a couple of months).
These are the dangers of going through old disks.

Although this can happen as a result of abrasive contamination
of a disk or drive, it is a relatively rare occurrence.

There is also nothing subtle about it.  The source of the
damage/contamination will be grossly obvious if the surface
of the disk(s) is examined visually.

I would not start to diagnose with this mindset.


But once you've established a pattern of good disks, then suddenly
start having failures, you've either come across a "bad lot" of disks
or you've suddenly had either contamination of the disk drive or a
hardware failure/glitch. Of the 3, the 2nd is the most likely.


Or your system has become flaky as a result of some other
problem...


I've had a fair bit of experience with this, and have had others
confirm it as well. It happens fairly regularly when you are going
through an old pile of media.


Yes, if some of them are grossly contaminated or have
disintegrating coatings.  I've never seen it happen if
each disk is examined before insertion.

I actually keep a "sacrificial" drive just for the purpose
of reading suspect disks.  Once in over a hundred disks I
may find one that is a problem--but I've never had a problem
disk that wasn't apparent upon visual inspection.


The easy way to check is once you see a pattern of failing disks, take
the "next few" to another system/drive and check them there, if ok see
if it fails on your test system. If it does, visually inspect the disk
and perhaps try it back on the other system.


This could also indicate that the "test" drive is marginal, and the
"reference" drive is not.


Of course, you might bugger two drives, but I really think they can be
cleaned.


Except in the case of an abrasive disk, which may do irreparable
harm to the head--again a *very rare* situation!

-michael

AppleCrate: An Apple II "blade server"!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."