Hold bit and UA response.

Paul.A.Suhler at certance.com Paul.A.Suhler at certance.com
Tue May 17 14:26:29 PDT 2005

* From the T10 Reflector (t10 at t10.org), posted by:
* Paul.A.Suhler at certance.com

Hi, Kevin.

I don't recall any discussion on the point when this first went into SSC.
I'm unable to construct a scenario where the application client that issued
the command needs the unit attention.  (I can see that it would be useful
if the HOLD bit were not set and IMMED was.  Then the application client
could poll until it sees the UA, then start talking to the MAM before
threading, etc. is finished.  *If* the device actually allowed that, which
isn't a given.)

The issue is now whether there would be any application clients that would
be broken by *not* getting the UA, were the change to be made.


Paul Suhler
Firmware Engineer
Quantum Corporation
1650 Sunflower Avenue
Costa Mesa, California  92626
(714) 641-2485 (voice)
(714) 966-7328 (fax)

                      "Kevin D Butt"                                                                                                   
                      <kdbutt at us.ibm.co        To:       t10 at t10.org                                                                   
                      m>                       cc:                                                                                     
                      Sent by:                 Subject:  Hold bit and UA response.                                                     
                      owner-t10 at t10.org                                                                                                
                      05/17/2005 12:03                                                                                                 

In SSC-3r01c under the Load/Unload command, Clause 7.2 pg 76 there is this
description of the HOLD bit.

A LOAD bit of one and a HOLD bit of one specifies if the medium has not
been moved into the logical unit, the
medium shall be moved in but not positioned for access. The EOT and RETEN
bits shall be set to zero. Following
successful completion, the device server shall return GOOD status. If both
the medium and device server support
MAM, the device server shall generate a unit attention condition for all
initiators and the additional sense code shall

My question is if the intent is that the UA be generated for "all
initiators" as is stated, or if the intent is to generate the UA for "all
other I_T Nexuses"?


Kevin D. Butt
Fibre Channel & SCSI Architect, IBM Tape Firmware,
6TYA, 9000 S. Rita Rd., Tucson, AZ  85744
Tie-line 321; Office: 520-799-5280, Lab: 799-5751, Fax: 799-4138, Email:
kdbutt at us.ibm.com

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