Re: Controller trashes FS (what's new)

Doug Ledford (
Sun, 26 Jan 1997 18:39:57 -0600

> Date: Sun, 26 Jan 1997 14:29:10 -0500 (EST)
> From: "Richard B. Johnson" <>
> I have been having trouble with SCSI Controllers.
> I got this Pentium System with an AHA-2940 Controller. The aic7xxx driver
> is apparently not being maintained so no bugs were getting fixed. These
> bugs were not killers, just little things like:
> o System crashes when you execute ls on a MS-DOS file system if
> the partition size is greater than 500 megabytes. These things
> were reported by myself and others during the past year.
> o System crashes when I attempt to use an EXABYTE tape drive. This
> was explained as a fault of the controller to properly handle
> disconnect (EXABYTE doesn't run sync and doesn't disconnect).
> Anyway..............
> So therefore, I spent a lot of money and bought a Bus Logic BT-958
> SCSI Controller. This had been recommended because, amongst other things
> "It had the best written Linux driver"....
> Last night it trashed 3 file-systems, two were not even mounted. The
> Linux root partition was not recognizable as a file-system of any known
> type. This is an ext2 file-system. My "/home/user" partition was not
> repairable using e2fsck although I was able to copy scrambled files off
> to a network file-server. Most are 'C' sources and can be repaired.
> I'd suggest you have serious hardware problems if both the 2940 and BT-958 have
> given you problems. The only way for an unmounted file system to be trashed
> would be if either the controller is bad or if a SCSI WRITE command had its
> data modified to point somewhere else on the disk.

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.

As for the Adaptec, there is a test version of a new Adaptec driver released
just a few days ago by Dan Eischen (he is the one responsible for converting
the FreeBSD driver to linux compatible, then Dean takes what Dan has and makes
the needed patches usually, including touching up things that Dan doesn't get
done absolutely cleanly). If I remember correctly, you can grab the patch
from or something like that.

As for all of the conversations about disks formatted with one controller or
another and switching, I've never had a problem switching SCSI controllers,
but then again I always disable extended translation entirely, then make a
root partition that falls into the first 1024 cylinders. It seems that all
SCSI cards can handle this setup (they should anyway :)

* Doug Ledford                      *   Unix, Novell, Dos, Windows 3.x,     *
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