>
> -> On Thu, 5 Oct 2000, Lawrence Walker wrote:
> ->
> -> > I have a hard to replace dsdd floppy disk that produced a
> -> > screeching noise while attempting to read it on a win98 box under
> -> > Dos using a Dos program.
>
> The screeching is caused by lack of lubricant on the disk surfaces.
> The drag caused by this will sometimes slow the disk rotation enough
> to cause errors, even though enough of the original disk surface
> remains to allow reading.
>
> -> >I quickly removed it and tried to read it
> -> > on another Dos box also with a HDFDD. No screech but only the ->
> > directory was readable, not the contents. I checked the original ->
> > FDD again using a scrap dsdd floppy and had no trouble with it. -> >
> Anyone have any thoughts as to what would have caused this ? -> ->
> Whenever I have heard that horrid squeal, it has been followed with
> the -> disappearance of the magnetic media on a track or cylinder.
>
>
>
> Whenever I've had this problem occur it has been caused by improper
> storage of the subject disk, usually in an area of high humidity and
> warm temperature. When the disk surface shows a white
> splotching/spotting, lighter brown splotching or other discernible
> discoloration, it is caused by a mold or fungus that eats away the
> lubrication from the disk surface. This splotching can cover large
> areas and be very noticeable or it may be hard to discern. It may
> cover the entire surface of the disk, or it might only be seen in the
> head slots. If the rotational position of the disk has not been
> disturbed since its removal from storage, rotate it 1/2 the width of
> the head slot and look for a difference in coloration on the magnetic
> surfaces.
>
There does seem to be a slight discoloration in spots. What was
the original lubrication comprised of. Was it just something
naturally occuring in the oxide ?
> I've come up with a solution (no pun intended) that will usually allow
> the data to be recovered if the disk isn't too badly damaged, like Don
> mentions (above). This procedure also applies to 3.5" disks. Examine
> the surface of the floppy before you put it in a drive for the first
> time, especially if it has been stored in a humid, warm area or if you
> don't know where it has been stored. Look for the splotching. If it
> is present, then be ready to immediately make a copy the first time
> you insert the floppy into a drive. You may only have this one chance.
>
> Apply some 91% (non-scented) or preferably 99% Isopropyl Alcohol to
> both sides of the disk in the head slot area. You want the alcohol to
> be absorbed onto the anti-friction liner of the floppy jacket, and you
> want enough of it so that it lasts through the reading/copying
> process. It may help to pucker the jacket to aid in the absorption of
> the fluid. Rotate the disk inside of the jacket enough that you are
> sure it is thoroughly wetted. Don't wet it so much that fluid is
> dripping off, though. If it is, shake off the excess, head slots away
> from you. The dripping and slinging of alcohol inside the disk drive
> mechanism is not good for the lubricated parts inside nor for the
> powered up electronics. INSURE EVERYTHING IS READY TO READ/COPY. Now,
> insert floppy and quickly perform the read/copy. I highly recommended
> that you have two floppy drives for doing this, unless you can read or
> copy the diskette in one pass. If not, you may have to wet the floppy
> more than once.
>
> If you get errors while reading, (S)kip or (I)gnore them if (R)etry
> doesn't work on the first couple of retries. The alcohol evaporates
> quickly, and you risk destroying areas of the disk that may have been
> readable had the alcohol remained.
>
> The alcohol accomplishes several things. It acts as a replacement for
> the missing lubrication, it helps scrub the fungus residue from the
> disk surface (which ends up on the jacket liner), it protects the
> heads from the abrasion of the molded areas and it keeps the heads
> flushed during the data recovery process. Due to the lubrication, the
> diskette will also rotate at the proper speed and timing/sync caused
> errors are eliminated.
>
> Alcohol is fairly inert in respect to the plastics used in many floppy
> drives. Also, if the drive used in this process is single sided,
> alcohol will not weaken the adhesive commonly used to attach the
> pressure pad.
>
> I've found that the best type of floppy storage for preventing this
> lubricant eating fungus, other than a proper storage environment, is
> an airtight container. Ziplock type bags work well.
>
> Bill
>
> whdawson
>
>
Thanks Bill. This is just what I was looking for.
I have an old Xerox 51/4 cleaning kit with spare cleaning disk
issues which uses isopropyl. Perhaps using that first on the fdd will
clean the heads and also leave a little on the heads for better
lubrication. I'll also use a little on the disk itself as you suggest.
This set was one that I acquired recently, so I don't know under
what conditions it was stored. Seems like I'll have to check some
of my older disks as well even tho my place is not especially hot or
humid. I have seen splotches occasionally on disks but just
considered it water or alcohol residue like you often have on old
audio records.
Great info, the cc m-l comes through again.
ciao larry
Reply to:
lgwalker_at_look.ca
Received on Mon Oct 09 2000 - 15:31:42 BST
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