[T10]Reset of a SCSI Target device

Spalding, AlanC Alan_Spalding at adaptec.com
Thu Dec 5 21:00:25 PST 2002

* From the T10 Reflector (t10 at t10.org), posted by:
* "Spalding, AlanC" <Alan_Spalding at adaptec.com>
Hi Laurent,

You should be maintaining Unit Attention state for each LUN in your target
(see SAM-2 rev 23 page 73 5.8.5 unit attention condition for details).

Basically you should be generating a Check Condition Status (02h) and
preparing Sense Data with a sense key value of 06h - unit attention, ASC
value of 29h, ASCQ value 00h (see SPC-3 spec for ASC/ASCQ values - table
B.1, and Request Sense data information including sense key). The initiator
will issue a Request Sense command on receipt of the Check Condition status.
The initiator will perform negotiation on the 1st data transfer request
after receiving a Check Condition status. This next command will most likely
be a Request Sense command. The initiator may also renegotiate on a
subsequent command after the Request Sense.

However, certain commands are excluded from returning check condition status
on unit attention state (e.g. Inquiry and Report Luns). The SAM-2 section
mentioned above has all the details. Note also that this unit attention
state is held by your target for each initiator.    


Alan C. Spalding
Intra-site work phone # 864-8369
Work phone # 949-455-8369
Work Fax # 949-455-8406

-----Original Message-----
From: Petit Laurent [mailto:laurent.petit at barco.com] 
Sent: Thursday, December 05, 2002 5:37 AM
To: 't10 at t10.org'
Subject: [T10]Reset of a SCSI Target device

* From the T10 Reflector (t10 at t10.org), posted by:
* Petit Laurent <laurent.petit at barco.com>

I am currently developing an external SCSI-3 target device and I wonder what
to do in case of reset or power off/on of the device.
My device supports PPR negotiation and is correctly detected at 160 MB/s by
a Windows 2000 machine with an adaptec 39160 board. If I reset my device,
the transfer parameters go back to the default mode which is narrow
asynchronous. Is there any way to indicate to the initiator that my target
has been resetted and thus that PPR negotiation has to be performed again ?
What happens now is that the initiator issues an INQUIRY command expecting
the data phase to be synchronous...
Is there something specified in the SCSI standard indicating how the target
should behave ?

Thanks for your help,

Laurent Petit
Design Engineer
Rue du Bosquet 7				1348 Louvain-la-Neuve
Tel: +32 - 10 - 45 49 04		Fax: +32 - 10 - 45 46 36 
Tel direct: +32 - 10 - 48 64 40
laurent.petit at barco.com			http://www.barco-silex.com
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