Subject: Re: Luns
To: David Jones <>
From: Michael L. Hitch <>
List: amiga-dev
Date: 07/10/1995 08:40:46
On Jul 10,  9:16am, David Jones wrote:
> > cgd
> > Sun Jul  9 05:30:46 EDT 1995
> > Update of /a/cvsroot/src/sys/scsi
> > In directory
> > 
> > Modified Files:
> > 	scsiconf.c 
> > Log Message:
> > QUANTUM P105S 910-10-94x A.3 -> SDEV_NOLUNS
> I find this interesting - the Quantum drive apparently does not grok
> LUNs.
> I had this exact drive on my Amiga for a long time.  I never got
> it at multiple LUNs.  I then moved it to my Sun3/260, and it showed
> up at multiple LUNs.  A Quantum Lightning 730 also shows up at multiple
> LUNs.

  What version of NetBSD are you using?  In -current, the Amiga drivers
are setting the LUN in the SCSI command.  I suspect that most of the
drive listed in scsiconf.c do not use the LUN in the IDENTIFY message
(and some probably don't even do the message-out when selected with
ATN).  Older drives will probably respond appropriately to commands that
have the LUN embedded in the command.  I had added that code to all the
Amiga drivers when I started getting muliple LUN results on reprobes.

> - Is it normal for a drive that doesn't understand LUNs to either
>   not respond to all probes, or to generate illegal request errors
>   for LUNs other than 0?

  A drive that does not use the IDENTIFY message is probably only going
to look at the old LUN field in the second SCSI command byte.  The SCSI-2
documentation I have indicates that the IDENTIFY message is mandatory
for SCSI-2, but that the LUN field in the command is still allowed for
compatibility with some SCSI-1 devices.  It's also possible that some
drives may have buggy handling of non-zero LUN values for the IDENTIFY

> - How 'come this drive behaved itself on the Amiga, both under NetBSD
>   and AmigaOS, both of which, as far as I know, support LUNs?

  Probably because the Amiga drivers set the LUN in the SCSI command if
they even probe multiple LUN devices.


Michael L. Hitch			INTERNET:
Computer Consultant
Office of Systems and Computing Services
Montana State University	Bozeman, MT	USA