Charles Hannum said:
>    cd0(bt0:4:0): illegal request, data = 00 00 00 00 20 00 00 00 00 00
> That's an `illegal opcode' error.  Are you sure that drive supports the
> SCSI 2 audio commands?

It turns out I've been seeing this on my Archive tape drive, when it first
tries to read a tape after I've changed tapes.  (It then complains that it
cannot set the mode.)  If I try again to read the tape, it works fine,
going through the usual hunting process to figure out the tape density and
then reading it.

[Hmm, maybe it's just the first time after boot; I just tried to reproduce
it, and it only happened the very first time.]  Is the tape driver attempting
a SCSI2 mode sense or something like that?  At boot time, the driver declares
it to be a SCSI1 tape drive, as well as a "rogue" (and since the driver
purports to have detailed knowledge of the drive's characteristics, I'd think
that it would know which opcodes would and wouldn't work).

The specific error message is (gee, it would be nice if it printed the
SCSI command block, too):
st0(aha0:5:0): illegal request, data = 00 00 00 00 00 00
st0: cannot set selected mode