Floppy woes ...

From: Michael Brutman <mbbrutman_at_bresnanlink.net>
Date: Wed Jul 4 19:28:35 2001

Thank you everybody for the suggestions. Here is how things
finally shook out.

The Pentium machine had a real, 360KB drive in it borrowed from
a PCjr. (I had stated that in the original note.) Formatting
issues between 1.2MB drives and 360KB drives were not part of the
equation.

I tried formating the diskettes (double density, double sided) in
both the 360KB drive on the Pentium and the 360KB drive in the
PCjr. This did not seem to make a difference.

Diskettes formatted and written by the Pentium machine were
usually unreadable in the PCjr. In a few tests they were also
unreadable in a second PCjr. Sometimes I could get a directory
or copy a file, but usually I was getting the familiar
"Abort, Retry, Ignore." A diskette "refresh" utility was reporting
lots of read errors on sectors, some recoverable and some not.
Diskettes written by the Jr were readable on the Pentium.
Old diskettes written years ago were readable everywhere. (These
were written by yet a different drive.)

I deduced that since the Pentium 360KB drive was writing the
diskettes and two PCjrs couldn't read them, that it must be the
Pentium 360KB drive causing the problems. So I swapped it out
and put a 1.2MB drive in it's place. I know about the head width
problems, but would you believe that one of the Jrs was able to
read diskettes created on the 1.2MB drive?

To make a long story short, the 360KB drive in the Pentium was ok,
the 1.2MB drive can write 360KB diskettes that are readable on
the PCjr, and one of the PCjr drives is flakey.

I think I was unlucky in my early testing when both Jrs balked
at the diskettes created on the Pentium. One of the Jrs drives is
know known to be bad, one is confirmed good, and the 360KB drive on
the Pentium is good, yet a diskette created on the Pentium caused
read errors on both Jrs, which led me to suspect the wrong drive.
I've not been able to reproduce that error again.

Now for the bad drive ... If I clean the rails with alcohol and
lube them with silicone spray, it does a slightly better job of
reading foreign (i.e.: not its own) diskettes. Based on this,
methinks that the head is not being positioned exactly where
it should be. However, those rails are pretty clean now and
the problems persist. It's an old Qume drive, 1/2 height.
I'm saving the drive for now, but a flakey 5.25 inch drive isn't
of much use.

And I've also learned that DOS 2.1 does NOT tolerate diskette
errors during the boot process. :-)
Received on Wed Jul 04 2001 - 19:28:35 BST