Re: Controller trashes FS (what's new)

Leonard N. Zubkoff (lnz@dandelion.com)
Sun, 26 Jan 1997 18:43:11 -0800


Date: Sun, 26 Jan 1997 18:39:57 -0600
From: Doug Ledford <dledford@dialnet.net>

The BusLogic is the most reliable driver I have seen under linux. It isn't
absolutely perfect though. I had one in a machine where I had three narrow
SCSI devices and one Wide SCSI drive. I didn't have a wide SCSI cable at the
time I installed the drive, so I used the narrow-to-wide adapter that came
with the drive and plugged this wide drive into the narrow SCSI cable. The
thing wouldn't work at all, and it was easy to tell it was missing every other
byte from the wide drive when you looked at the boot up messages. After
unplugging the drive, which I did as the machine was coming up but before the
SCSI BIOS had started, the BIOS didn't find the drive (as it shouldn't have),
but after the boot was complete, the system was somewhat unreliable. Then,
next time I rebooted the machine, using a full power down cycle, the card came
up fine and I never had another problem, tape backups and everything.

If you were using a BT-958, the most likely reason this occurred is that using
Wide to Narrow adapters is only correct in certain situations. The drive and
controller don't know how many wires are actually connected, so if you have a
Wide controller and a Wide drive, they will happily negotiate wide transfers
even if the wiring isn't there to support it. BusLogic's AutoSCSI utility
allows you to disable wide negotiation for particular devices, in which case
such cabling will work. It's generally safe to use the adapters without
setting AutoSCSI options so long as either the controller or drive is Wide but
not both.

Leonard