Reading DC6150 XENIX 2.3.2 tapes under ODT

[Michael Squires]

I'm moving from a XENIX 2.3.2 system to an ODT system.  The old system
ran XENIX 2.3.2 GT and used a Cipher 150MKII SCSI tape drive to write
150MB DC6150 cartridge tapes (QIC-150, I think).  The target system
has a Archive Scorpion 2150S running off an Adaptec 1542B controller
(which also supports the primary drive).

The tape drive is recognized by the Adaptec (correctly).  The tape unit
rewinds and retensions tapes correctly, but has yet to read any tape
(DC600A or DC6150) yet.  XENIX tapes start off correctly but terminate
with a checksum error, very quickly.

The drive appears to be installed correctly according to "mkdev scsi" and
"mkdev tape" (at least it's being recognized).  So far my best guess is that
I have a defective unit; any other ideas?