8mm Exabyte drive on 3/280-16 SunOS 4.0.3

[Sun Workstation Support]

We just installed an Exabyte 8mm tape unit on a 3/280 running SunOS 4.0.3,
and are intermittently running into the following problems when reading &
writing to/from the unit.  Has anyone seen these problems (and/or found a
solution)?  The unit is pretty much unusable right now, as using it causes
system reboots...  

Thanks in advance.
Bill Heiser

Nov  2 11:47:40 tdw508 vmunix: ECC Error Register d4<INTR,INTENA,CE_ENA,WBACKERR>
Nov  2 11:47:40 tdw508 vmunix: DVMA = 0, context = 4, virtual address = 4029b48
Nov  2 11:47:40 tdw508 vmunix: pme = 20000000, physical address = 1b48
Nov  2 11:47:40 tdw508 vmunix: panic: writeback error
Nov  2 11:47:40 tdw508 vmunix: syncing file systems... 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
done
Nov  2 11:47:40 tdw508 vmunix:
Nov  2 11:47:40 tdw508 vmunix: dumping to vp f12de2c, offset 225951
Nov  2 11:47:40 tdw508 vmunix: SunOS Release 4.0.3 (GENERICSMT) #1: Thu Oct 26 14:43:29 EDT 1989
Nov  2 11:47:40 tdw508 vmunix: Copyright (c) 1989 by Sun Microsystems, Inc.
Nov  2 11:47:40 tdw508 vmunix: mem = 16384K (0x1000000)
Nov  2 11:47:40 tdw508 vmunix: avail mem = 15400960

The device entries look like this:

crw-rw-rw-  1 root      64,   4 Nov  1 14:51 nrsmt0
crw-rw-rw-  1 root      64,  12 Oct 26 15:17 nsrsmt0
crw-rw-rw-  1 root      64,  20 Oct 26 15:17 nvrsmt0
crw-rw-rw-  1 root      64,   0 Nov  2 10:54 rsmt0
crw-rw-rw-  1 root      64,   8 Oct 26 15:17 srsmt0
crw-rw-rw-  1 root      64,  16 Oct 26 15:17 vrsmt0

Work:  heiser at tdw201.ray.com
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Home:  Bill.Heiser at f101.n324.z1.fidonet.org (Fidonet 1:324/101)
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