[comp.sys.3b1] Errors using 96tpi floppy disk

krohn@bae.bellcore.com (Eric Krohn) (04/27/91)

I've made numerous attempts to get a 96tpi floppy disk drive to work
with my 7300, but to no avail.  The first drive I tried is a Mitsubishi
MF504A-308U -- a 1.4 MB drive for a PC AT strapped (I think correctly)
to force it to "low" density mode (96tpi, 300rpm).  I format it with
	iv -ivw /dev/fp020 /usr/lib/iv/FD96nl
where FD96nl is a copy of FD10nl with sectors changed from 40 to 80.

Iv formats the drives but fails on the surface check:
Failed in Phase 3 - Surface Check: adding bad block on second write 880
iv: bad block 880 on device with no bad block table

Repeated attempts produce errors on different block numbers -- most are
880 or higher, one was 704.
If I format with FD10nl, it works fine but only uses half the floppy.

Suspecting the floppy drive, I plugged in a Mitsubishi M4852 -- a 720KB
drive that worked in my old Callan Unistar.  On this drive, iv "succeeded"
in formatting and surface checking,  and I can copy data to the drive.
However, when I read the floppy I get errors starting at logical block 440 --
suspiciously similar to the physical block 880 above.

Now these errors are filling up my /usr/adm/errfile (I use the error daemon
packaged with MGR instead of the stock one):

Sat Apr 20 17:55:25 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8F00
Sat Apr 20 17:55:25 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8D00
Sat Apr 20 17:55:26 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8700
Sat Apr 20 17:55:26 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8500
Sat Apr 20 17:55:26 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8500
Sat Apr 20 17:55:26 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8700
Sat Apr 20 17:55:26 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8500
Sat Apr 20 17:55:27 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8D00
Sat Apr 20 17:55:27 1991: pid     0: #FDERR ST:8 TR:2E SR:3 DR:FFFFFFC0 DMACNT:FFFF DCRREG:F3 MCRREG:8D00
Sat Apr 20 17:55:27 1991: pid     0: :S:D::Unrecoverable floppy disk error

What do these mean?  Is my problem with the drive(s) or is my 7300 ill
or incapable of using a 96tpi drive?  I know others have done this okay.
Help!