tar backup ok but restore errors w/ scsi dat dds2

["Ralph Eagle" <ralph@kubinski.com>]

I think this might be a hardware compatibility problem, but you be the
judge.

Using tar, I can write a tape archive to the scsi dat drive (tar cvf
/dev/st0 /usr/kbmosas) without any errors but when I try to read the tape
back (tar tvf /dev/st0  or  tar xvf /dev/st0), I get the following messages
intermingled with the verbose output from tar listing the files in the
archive;

tar: Skipping to next header
tar: Archive contains obsolescent base-64 headers
tar: Error exit delayed from previous errors

The messages do not seem to be consistent - sometimes the base-64 header
message does not happen and once or twice out of about ten or twenty tries,
I can read the tape back without an error. It seems like the bigger the
backup the more likely the problem. I've put the scsi card and drive in two
other boxes 1) an old SCO box running on a 486DX266 and  2) Debian 3.1
(2.4.18-bf2.4) running on an IBM PC Server (PentiumII) and had no problems.

I'm running the 2.4.18-bf2.4 kernel with an Adaptec AHA-2940UW scsi card and
a Seagate STD28000N drive on a Celeron 2.4GHz box w/ 512MB RAM. The tape
drive is the only scsi device in the system. Here is more info:

tar version: 1.15.1-2

scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.4
    <Adaptec 2940 Ultra SCSI adapter>
    <aic7880: Ultra Wide Channel A, SCSI Id=7, 16/253 SCBs

Vendor: ARCHIVE   Model: Python 04687-XXX  Rev: 6610
Type:   Sequential-Access                  ANSI SCSI revision: 02
(scsi0:A:6): 7.812MB/s transfers (7.812MHz, offset 15)

st: Version 20020205, bufsize 32768, wrt 30720, max init. bufs 4, s/g segs
16
Attached scsi tape st0 at scsi0, channel 0, id 6, lun 0
st0: Block limits 1 - 16777215 bytes.

st0: Error with sense data: current st09:00: sns=70 5
    ASC=26 ASCQ=0
raw sense data: 0x70 0x00 0x05 0x00 0x00 0x00 0x00 0x12 0x00 0x00 0x00 0x00
0x26 0x00 0x00 0x8f 0x00 0x04 0x00 0x00 0x00 0x00 0x00 0x3a 0x6b 0x40

shinzon:~# mt status
drive type = Generic SCSI-2 tape
drive status = 603980288
sense key error = 0
residue count = 0
file number = 0
block number = 0
Tape block size 512 bytes. Density code 0x24 (DDS-2).
Soft error count since last status=0
General status bits on (41010000):
 BOT ONLINE IM_REP_EN

I've tried what I know... any ideas?

Ralph Eagle
Kubinski Business Systems