Comments on 05-177r0 "write same"

Curtis Stevens curtis.stevens at wdc.com
Wed May 4 15:02:19 PDT 2005


* From the T10 Reflector (t10 at t10.org), posted by:
* "Curtis Stevens" <curtis.stevens at wdc.com>
*

Jim

	I guess that response 1a to your questions was unclear.  The SAT WG
chose to reference SCT LBA Segment Access in place of SCT.
 
-------------------------------------------------
Curtis E. Stevens
20511 Lake Forest Drive #C-214D
Lake Forest, California 92630
Phone: 949-672-7933
Cell: 949-307-5050
E-Mail: Curtis.Stevens at WDC.com
Ambition is a poor excuse for not having enough sense to be lazy.
 

-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of
James.C.Hatfield at seagate.com
Sent: Wednesday, May 04, 2005 1:08 PM
Cc: t10 at t10.org
Subject: RE: Comments on 05-177r0 "write same"

* From the T10 Reflector (t10 at t10.org), posted by:
* James.C.Hatfield at seagate.com
*
My issue is that the SAT document should refer to

      SCT LBA Segment Access is enabled
            instead of (just)
      SCT is enabled

That's all.

Thank You !!!
-----------------------------------------------------------------
Jim Hatfield
Seagate Technology LLC
   e-mail:  James.C.Hatfield at seagate.com
   s-mail:  389 Disc Drive;  Longmont, CO 80503 USA
   voice:  720-684-2120
   fax....:  720-684-2711
==========================================


                                                                           
             "Curtis Stevens"                                              
             <curtis.stevens at w                                             
             dc.com>                                                    To 
             No Phone Info             <James.C.Hatfield at seagate.com>      
             Available                                                  cc 
                                       <t10 at t10.org>                       
                                                                   Subject 
             05/04/2005 01:54          RE: Comments on 05-177r0 "write     
             PM                        same"                               
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




Jim

             I am confused by your issue.  This only thing you need to
check is
word 206 bit 2.  If it is 0, you can't use LBA Segment Access.  If it is 1,
you can.  The method of detection is contained in the technical report.


-------------------------------------------------
Curtis E. Stevens
20511 Lake Forest Drive #C-214D
Lake Forest, California 92630
Phone: 949-672-7933
Cell: 949-307-5050
E-Mail: Curtis.Stevens at WDC.com
Ambition is a poor excuse for not having enough sense to be lazy.


-----Original Message-----
From: James.C.Hatfield at seagate.com [mailto:James.C.Hatfield at seagate.com]
Sent: Wednesday, May 04, 2005 12:47 PM
To: Curtis Stevens
Cc: t10 at t10.org
Subject: RE: Comments on 05-177r0 "write same"

You are correct in stating that there is no documented standard
way to 'enable or disable' SCT LBA Segment Access, but there <is> a
documented way for the device to separately report that
     a) it supports (or not) SCT (in general)     <and>
     b) is supports (or not) SCT LBA Segment Access

It is vendor unique whether or not there is a way to change the settings
of these bits.

Please refer to the SCT Technical report (1701DT rev 5, page 5)
      IDENTIFY DEVICE, word 206
      bit 0 = SCT Feature set supported (includes SCT status)
      bit 2 = LBA Segment Access (AC2) supported

I request that the SAT document needs to address what to do if bit 0 is set
to one
and bit 2 is cleared to zero.

Thank You !!!
-----------------------------------------------------------------
Jim Hatfield
Seagate Technology LLC
   e-mail:  James.C.Hatfield at seagate.com
   s-mail:  389 Disc Drive;  Longmont, CO 80503 USA
   voice:  720-684-2120
   fax....:  720-684-2711

============================================================================

==
(from Curtis Stevens' notes of the discussion at the SAT meeting May 3
2005)

1. OPCODE - Is there a preferred hierarchy of choices for implementation?
      If a device does not support SCT, is there a preference for the other
2
      choices?

      Committee Respose:
      a. Wording was changed to reference SCT LBA Segment Access.
      There is no enable or disable for this capability.

3. Please clarify the meaning of "device implements SCT".  See 1a above.

4. What if the ATA device (target) 'supports' SCT, but does not have it (or
the LBA Segment Access subcommand) enabled?

Committee Response:
      There is enable/disable for SMART, but there is no enable or disable
for SCT.



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