hello Dave!
re: rebuild the kernal? -- problem lost target directory & files until
reboot.

Colin Wood's FAQ for mac68k mentions a patch for the sbc kernels which
i've been told doesn't apply to a Q700 since that machine uses an esp
driver. Jonathan's suggestion seems to have the genericsbc patch for
older macs in mind.

On Fri, 4 Jul 1997 06:28:25 -0500 (CDT) Dave Huang wrote...
> Anyways, if you'd like, I can compile a NetBSD-current kernel for you.
> Just send me any patches you want applied, and a kernel config file (or
> let me know if you want a GENERIC kernel).
> 
> My offer's open to everyone, btw... if anyone wants a mac68k kernel from
> -current sources, send me a kernel config and any patches you want, and
> I'll send you a kernel whenever I have some time :) (probably within a few
> days). Also let me know if you'd prefer .sit.hqx format or .tar.gz.uu (or
> .gz.uu or whatever :)
>
[Jonathan O'Brien's suggestion] 
> The problem you're seeing is similar to something I experienced
> about a year ago. Some scsi drives don't handle residual data
> pointers correctly (I don't fully understand the problem, just
> know of a potential fix). On my drive, I would create a file
> on the drive and the partition would no longer be accessable like
> you describe. The solution was to add an entry into the quirk
> table to force the "SDEV_AUTOSAVE" then build a new kernel with
> the change.
> 
> Here's an example entry in src/sys/scsi/scsiconf.c:
> 
>         {{T_DIRECT, T_FIXED,
>          "DEC     ", "RZ55     (C) DEC", ""},     SDEV_AUTOSAVE},
>
[faq pages]
> 6.21 NetBSD doesn't seem to like my SCSI disk. Is there any way I can prevent 
> this annoying filesystem damage? 
[snip]
> In order to fix the problem, Scott Reynolds (scottr@og.org) wrote the sbc scsi driver to replace the standard ncrscsi driver.
[snip]
> To enable this mode in the driver, simply add a `flags 0x5' to the sbc0
> line in your kernel config file, like so:
> 
>         sbc0 at obio? flags 0x5
[snip]
> 
> Finally:  If your target is one of those that is affected by a looser
> interpretation of the SCSI specification, it will require an SDEV_AUTOSAVE
> quirk in the quirk table in sys/scsi/scsiconf.c.  I believe there is some
> work going on to find a better overall solution to the problem, but a
> local modification to your tree will certainly do the trick for now.  How
> will you know if you're affected?  Usually, a corrupted file system
> results very quickly; 
[snip]
> There are several kernels compiled with the newer driver, so you will probably 
> want to use one of them instead. They are usually named
> something like GENERICSBC or kernelname-SBC.
[snip]
> Remember that many SCSI problems are the result of bad SCSI cables
> or poor termination.

any help is appreciated!

sincerely...brian w.
bwildasi@csulb.edu