Motherboard FDC or SCSI Card FDC?

Motherboard FDC or SCSI Card FDC?

Post by John Kenyo » Tue, 28 Sep 1999 04:00:00

My motherboard (Dell 486 w/bus speed set to 33MHz) is fitted with a
floppy controller which my 2.2.12 kernel recognises as an 8272A.

My SCSI adapter (ISA) has a floppy controller which is reported
as a PC87306.

According to the NSC website the PC87306 has a 16 byte FIFO buffer.

Does anybody know if the kernel driver makes use of this FIFO
Is there any advantage in using the PC83706 on the SCSI card in
preference to the motherboard.

The motherboard has the following (non) features:
No PCI. No Plug and Pray.
Configured to accept a 486DX2, has an Evergreen 5x86/133 upgrade fitted.
BIOS settings for Floppy set to "Auto" - disabled if another controller

The SCSI card just has one setting "Enable or Disable", and is plugged
into a plain 16 bit ISA slot.

Any ideas?


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1. SLS 1.03, FDC TMC880 can't partition scsi disk

I've been reading this group for a few months (plus the FAQ's) and finally
took the Linux plunge (first on a spare parts PC, then I ditched my DOS

My configuration includes a 486DX33 w/AMI bios, 16MB RAM, Future Domain
TMC880 controller, Maxtor 7245 SCSI driver, Conner 162MB IDE,
Sony CDU541 CDROM and a 3com
3c503 board.

Everything has gone well on the install  even no clock tuning in X386,
except for my SCSI disk drive.  When I run "fdisk /dev/sda" it gives me
an impossible number of sectors.  It claims the geometry is 4 heads,
1944 cylinders and 72 sectors, which fdisk doesn't like.  (It is also
incorrect  these settings make the disk out to be 286MB, but it's only
a 245MB).  So, I changed the number of sectors manually to 60, which seemed
reasonable.  I made a large partition, then rebooted.  Upon reboot,
everything looks okay.  Then I did "mke2fs /dev/sda1"  looked good, until
I got massive numbers of bad sectors.  I then rebooted again, and my
partition was gone!  So, I tried running "fdisk /dev/sda" again and
fdisk told me that there was a SCSI read error on cylinder 0.  I checked
and rechecked the termination, cables (I had a bad one for awhile) and
I/O addresses.  There were no problems.  I rebooted again, reset heads/
cylinders/sectors and everything was okay again.  Ran the mke2fs again,
and it didn't work again (and my disk was thrashed again after the next
reboot).  I've also tried a CDC94155 SCSI disk and had similar problems
(but I got NO geometry readings out of it).  (My fdisk is 0.93, kernel
is 99pl12 and SLS is 1.03).

Am I missing something really basic?  I thought geometries for SCSI really
didn't matter, as long as one made sure it was smaller (or equal) to the
actual disk capacity.  I hope I didn't miss a FAQ along the way.  I've
got about 10 of them around and couldn't really find much useful.

Thank you for any information.

Nathan D. Lane, MIS Analyst and VP of Triicon Systems, Inc.

Making the Title Insurance World an Easier Place!

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