In message <199507221520.RAA00197@rumolt.teuto.de>you write:
->> ahb0 targ 4 lun 0: <TOSHIBA, CD-ROM XM-3501TA, 2694> SCSI2 5/cdrom removabl
e
->> cd0 at scsibus0: drive empty
->                   ^^^^^^^^^^^

If you look closely, you will discover the drive is still initializing and 
thus seems to send someting like "ask me later for info", i.e. DEVICE BUSY 
reply.
If you insert a delay before the probing and after the SCSI-bus-reset you will 
get correct information.  This worked at least for my 3601, but I decided to 
like it better if booting goes faster...

Gruesse
       Oskar

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 					Tragbar ist, was nicht herunterfaellt.
						    oskar@zappa.unna.ping.de
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