On 01/15/2017 04:36 PM, Martin McCormick wrote:
I must first say a big thank you to everybody who helped.
I got it working and here is what happened and how to
format a totally blank diskette.
The man page for setfdprm should have had at least one
example of how to use it since syntax, especially for something
one doesn't use every day, is not intuitive and can cause hours of prodding and
head-scratching/banging.
In my searching via Google and reading some of the
articles and discussion group postings, I learned that there is a
companion to setfdprm which is getfdprm. I put in a good and
formatted floppy and ran getfdprm on a 1.44 Mb disk. The
application produced
DS HD sect=18
This occurs after you have spun the disk to mount it or done
anything else to make the disk turn for reading.
If you eject the diskette, the value stored in setfdprm
vaporizes, assuming that one's floppy drive's disk-change switch
is working.
I figured that this value or
DS DD sect=9
for a 720 K diskette was worth passing to setfdprm so I wrote the
following shell script:
#!/bin/sh
#1.44Mb disk Uncomment line below.
#setfdprm /dev/fd0 DS HD sect=18
#720K disk Uncomment line below to use it.
#setfdprm /dev/fd0 DS HD sect=9
#fdformat /dev/fd0
It will begin by identifying that this is a double-sided disk and
will start laying down tracks from 0 to 79 and then verify their
presence.
You can skip the verification process in fdformat but I
don't advise it as I tried some old 720K disks that formatted all
80 tracks and then track 0 was dead on all of them.
Another warn-out disk formatted and verified until track
76 was reached and then it cratered with the same error that
befell the 720K disks.
A new (unused until now) 1.44 Mb disk formatted and
verified all 80 tracks so the drive appears to have no
electro mechanical issues on good media.
On the disk with a dead track 76, the error caused the
heads to seek all the way back to track 0 and then forward to 76.
One could hear it rip-sawing back and forth which was probably
good exercise for a drive that doesn't get much usage these days.
After trying to read track 76 many times, the verification
aborted with a message stating that this track was bad.
Anyway, this has been an interesting journey down memory
lane. Stuff just works a lot better these days than it used to.
Martin McCormick WB5AGZ
About a year ago, or maybe two, I bought a pack of Radio Shack floppies.
I think ten or twelve in
the pack. Most of them had errors right off the bat! I don't know if
you can trust old floppies!
--doug