There's  often a tradeoff whether a changer expects block descriptors
disabled or not. I seem to recall in a brief review of the chio code
(which I can't do at present as I'm shutting my systems down prior
to a two week trip) that the ch driver didn't try both. Look at st.c
for an example.

On the other hand, the error would be usually reported as Illegal
bit in CDB- not Invalid Operation code. Is there a switch for
this device to enable/disable changer mode?

On 21 Sep 1998, Chris Jones wrote:

> Where I work, we recently ordered a "CD duplicator," meaning a device
> with a CD burner, a hopper full of blank CD's, and a robot to move the
> CD's into and out of the CD-R drive.  I naively assumed that NetBSD's
> ch(4) driver would be able to drive this thing; unfortunately, that
> doesn't appear to be the case.
> 
> When I boot, I get this:
> 
> Sep 21 12:18:16 hideo /netbsd: ch0 at scsibus0 targ 6 lun 0: <CEDAR, DESKTOP P100, 1.10> SCSI2 8/changer removable
> Sep 21 12:18:16 hideo /netbsd: ch0(ahc0:6:0):  Check Condition on CDB: 0x1a 08 1d 00 18 00
> Sep 21 12:18:16 hideo /netbsd:     SENSE KEY:  Illegal Request
> Sep 21 12:18:16 hideo /netbsd:      ASC/ASCQ:  Invalid Command Operation Code
> Sep 21 12:18:16 hideo /netbsd: 
> Sep 21 12:18:16 hideo /netbsd: ch0: could not sense element address page
> Sep 21 12:18:16 hideo /netbsd: ch0: offline
> 
> If I try "chio status", I get the same thing, minus the last line.
> 
> So, I'm probably going to have a peek at the code for this, but I'm
> not optimistic about my ability to solve this problem, because
> anything with SCSI and "address page" frightens me.
> 
> Does anybody else have any ideas?
> 
> Chris
> 
> -- 
> -----------------------------------------------------cjones@math.montana.edu
> Chris Jones                                          cjones@honors.montana.edu
>            Mad scientist at large                    cjones@nervana.montana.edu
> "Is this going to be a stand-up programming session, sir, or another bug hunt?"
>