Subject: Re: SCSI CD changers supported?
To: None <current-users@NetBSD.ORG>
From: Christoph Badura <>
List: current-users
Date: 09/12/1996 02:13:00
Tom I Helbekkmo writes:
>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

If the drive supports disconnect/reconnect it must support the
IDENTIFY message.  That's a requirement of the SCSI protocol.

>  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?)

That's probably not the case.  The only way the driver could know that
the drive won't disconnect is by the drive rejecting the IDENTIFY
message which it must not do if you have configured it to do
disconnect.  However it is at the drive's (target's in SCSI speak)
discretion to disconnect.  There isn't a way for the driver
(initiator) to tell the drive to disconnect and when to disconnect.

>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?

No.  What I have described *is* SCSI-I.

Christoph Badura

You don't need to quote my .signature.  Everyone has seen it by now.
Besides, it doesn't add anything to the current thread.