Problem with multi-volume SCSI tape backups (using cpio/afio)

[Steve Ralston]

Has anyone else had problems performing multi-volume cpio tape backups
to an Archive 150 SCSI tape?

Environment:	386/20 clone, 8 Mb (non-caching)
		Adaptec 1542A SCSI host adapter
		Archive 150 tape drive (2150S ?), using DC600A & DC6150 tapes
		SCO ODT 1.0 (System V, Release 3.2.1)

Backup command:	cd /
		find . -depth -print | cpio -ocB > /dev/rct0

Error Condition:	At end-of-tape, backup process halts; no messages,
			no warnings, no prompt for next volume.  Pressing
			the INTR key gets back the shell prompt but kills
			the backup-in-progress.

I have also tried the above command using "afio -o -b 5k /dev/rct0" instead
of the cpio command.  The result was almost identical, except a message
something like:
	afio: "/dev/rct0", Bad address
is printed at end-of-tape, terminating afio and returning to the shell prompt.
(Looks like afio is reporting system errno = EFAULT to me; errno=14 in
<sys/errno.h>).  I would rather be using cpio instead of afio, in case I ever
need to recover from a hard crash and afio is not readily available, but
cpio just ain't cuttin' it here.

The afio man page says the -s option (volume size limit) is "Useful with
finite-length devices which do not return short counts at end of media (sigh)."
Yes, I can effectively use the "-s 120m" to limit afio archives to 120 Mb
for DC600A carts, or "-s 150m" for DC6150A carts.  Hell I even made mods
to the afio sources so that I can mix both tapes at random.  BTW: Thanks
to Mark Brukhartz @ Lachman Associates for afio (if he is still there).

Can anybody confirm or deny whether "short counts and end-of-media" could be
the problem?  Could this be a SCSI tape driver bug?  Any other suggestions,
including other backup methods would be welcome.  Thanks for any info.
-- 
Steve Ralston    (sralston at srwic.UUCP || ..!uunet!ncrcom!ncrwic!srwic!sralston)
235 N Zelta, Wichita, KS 67206