Had to change a definitely worn 5-1/4" floppy drive and fell over a
weird problem: how to test the drive(s)'s reliably ?
Situation: there's one 5-1/4" floppy drive, mounted as new and rarely
used, in a "big" box (running [DR-]DOS and Linux); the 5-1/4" floppy
drive in the text workhorse of the '286-puter had to be exchanged
against one from a stock which I had noted "hardly used" (it was
mounted as new, earlier, into a reserve-'486 which served as a fax
receiver). This latter one, however, cannot read a lot of the heap
of archive-diskettes of the 1.2 MB, 5-1/4" type. Especially puzzling
is the DOS error message, "Not ready error reading drive A" (the beast
is mounted as the A: drive in the '286); but there are other errors,
seemingly haphazard - "Disk not present, or drive error", or "Sector
not found drive A"; and rather frequent, "I/O error reading drive A".
This happens as well with used diskettes as with factory new, "DOS
formatted" ones.
That floppy drive cannot be simply technically bad (and has not
enough service time to be worn out) - a most striking example was that
it couldn't read (using "chkdsk") 8 from a pack of 10 factory-new (Sony)
diskettes, and not even format them: but after (re-)formatting these
diskettes (without problem) on the other floppy drive at the other
machine, it had no problems with them any more. On the other hand, it
did refuse only one diskette among three 10-packs of factory-new,
"no-name" ones of apparently different make.
Though it still wouldn't read number of the archive diskettes which the
other floppy drive (on the Linux-box) does digest without hickup; and
those archive diskettes are of the most divergent origin, writing
time, and age of use - no whatsoever "pattern" visible there.
This floppy drive just behaves "picky" (or over-correct ?)
One obvious reason would be a deviation from track alignment. But while
there are lots of generic as well as manufacturer-specific tools to
calibrate hard disks, I didn't find anything the like for floppy drives.
Another dilemma is to choose some reference diskette for such a measure
-- as new, and even used floppy drives of the 5-1/4" type are ever
harder to come by, and could as well be biased in an unknown way.
The 1.2 MB diskettes, btw, seem rather more robust than the 1.44 MB
floppies. And I've quite some archives on them, from the end-80ies on,
which I need to keep accessible.
// Heimo Claasen // <hammer at revobild dot net> // Brussels 2001-08-20
The WebPlace of ReRead - and much to read ==> http://www.revobild.net
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