verification leaves tape in bad state, 1.13.18

[Daniel R. Grayson]

If I try to verify my tape, I get an IO error, and then the tape is left in
such a state that an io error appears at the end of the file when trying to
read it.

    niobium# tar cvgVW rsync.snapshot "tape HOME 7, file 0, test rsync, `date`"
    rsync-2.4.4
    tape HOME 7, file 0, test rsync, Thu Dec 28 07:58:31 CST 2000
    tar: rsync-2.4.4/bin: Directory is new
    tar: rsync-2.4.4/man: Directory is new
    tar: rsync-2.4.4/man/man1: Directory is new
    tar: rsync-2.4.4/man/man5: Directory is new
    rsync-2.4.4/
    rsync-2.4.4/bin/
    rsync-2.4.4/man/
    rsync-2.4.4/man/man1/
    rsync-2.4.4/man/man5/
    rsync-2.4.4/bin/rsync
    tar: /dev/nst0: Cannot write: Input/output error
    tar: Error is not recoverable: exiting now

-----------------------------------------------------------------------------

niobium# printenv TAPE
/dev/nst0

niobium# tar --version
tar (GNU tar) 1.13.18
Copyright 2000 Free Software Foundation, Inc.
This program comes with NO WARRANTY, to the extent permitted by law.
You may redistribute it under the terms of the GNU General Public License;
see the file named COPYING for details.
Written by John Gilmore and Jay Fenlason.

from dmesg:

st: bufsize 32768, wrt 30720, max buffers 4, s/g segs 16.
(scsi0) <Adaptec AIC-7880 Ultra SCSI host adapter> found at PCI 18/0
(scsi0) Wide Channel, SCSI ID=7, 16/255 SCBs
(scsi0) Downloading sequencer code... 419 instructions downloaded
scsi : 0 hosts.
st: Unloaded.
st: bufsize 32768, wrt 30720, max buffers 4, s/g segs 16.
scsi0 : Adaptec AHA274x/284x/294x (EISA/VLB/PCI-Fast SCSI) 5.1.10/3.2.4
       <Adaptec AIC-7880 Ultra SCSI host adapter>
scsi : 1 host.
  Vendor: SONY      Model: SDT-5000          Rev: 3.30
  Type:   Sequential-Access                  ANSI SCSI revision: 02
Detected scsi tape st0 at scsi0, channel 0, id 3, lun 0
(scsi0:0:3:0) Synchronous at 5.0 Mbyte/sec, offset 8.