Subject: Re: SCSI CD changers supported?
To: Tom I Helbekkmo <tih@Hamartun.Priv.NO>
From: Brad Walker <>
List: current-users
Date: 09/10/1996 16:07:56
> On Tue, 10 Sep 1996, Michael L. Hitch wrote:
> >   Since your DRM-610 does not accept the LUN in the IDENTIFY message, it
> > may very well not accept the IDENTIFY message period [I have a Chinon
> > CDROM drive that does that].  If the device does not accept or honor the
> > IDENTIFY message, it won't be able to disconnect from the bus while the
> > device is busy, and nothing else can use the SCSI bus at that time.
> I have no idea what it does or doesn't do with this IDENTIFY message,
> but I do know that one of the DIP switches on the back selects whether
> the drive should do disconnect/reconnect or not.  I have it set to do
> this.  Is the problem that the SCSI driver doesn't know that the drive
> can do it?  That the lack of support for IDENTIFY keeps the driver
> from telling the drive to do disconnect/reconnect, and the drive won't
> do it on its own until it knows that the controller and/or driver can
> handle it as well?  (Can you tell I'm guessing, here?)

Set the switch for disconnect/reconnect. By not setting it you are telling the
drive to be SCSI-1 compliant and not SCSI-2 compliant. Though SCSI-2
initiators are required to work with SCSI-1 targets. Identify messages
are needed to support multiple LUNs which were added in SCSI-2. ANd
disconnect/reconnect is a feature of SCSI-2. 

> If the drive has support for disconnect/reconnect, but not for this
> IDENTIFY message, might there be an old (SCSI I) alternative way of
> doing it?  I'm all ears if anyone has good suggestions!

I HIGHLY doubt the drive does not have support for MSG_IDENTIFY if
it supports disconnect/reconnect.

-brad w.