Question about ROD token "well-known" type

Knight, Frederick Frederick.Knight at netapp.com
Mon Apr 25 09:04:30 PDT 2011


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1104253_f.htm">HTML-formatted message</a>

Yes, the intent is that it is optional.
		Fred
From: Joseph Glider [mailto:gliderj at almaden.ibm.com] 
Sent: Monday, April 25, 2011 10:20 AM
To: t10 at t10.org
Subject: RE: Question about ROD token "well-known" type
Thanks Fred. 
Given what you say, I wouldn't want to require that storage systems that want
to support the main copy offload function to also be required to support this
almost-WRITE-SAME capability. It increases the development burden for storage
systems to do so and it would be a shame to delay support of the main
function based on needing to support a function that isn't needed by
initiators because they already have a tool to get the job done. 
 Is support of well-known tokens separately configurable already, or can it
be? 
Jody Glider
STSM, Storage Systems and Servers Research
Tieline: 457-1853
External: 408-927-1853 
From: 
"Knight, Frederick" <Frederick.Knight at netapp.com> 
To: 
"Joseph Glider" <gliderj at almaden.ibm.com>, <t10 at t10.org> 
Date: 
04/25/2011 04:46 AM 
Subject: 
RE: Question about ROD token "well-known" type 
Sent by: 
owner-t10 at t10.org
________________________________
Yes, similar to WRITE SAME, but not identical. 
The primary difference is the ability to use multiple LBA extents (a scatter
write of zeros vs. a single extent in WRITE SAME).   The similarity to the
token operations, is that the device knows the data (zeros in this case), and
the application has a reference to that data (the token – the well known
zero token in this case). 
		Fred 
From: Joseph Glider [mailto:gliderj at almaden.ibm.com
 ] 
Sent: Thursday, April 21, 2011 5:58 PM
To: t10 at t10.org
Subject: RE: Question about ROD token "well-known" type 
This sounds like WRITE SAME, how is it different or better? It doesn't seem
to be solving a problem similar to the one that proxy read/write was proposed
for, or am I missing the point? 
Thanks, 
Jody Glider
STSM, Storage Systems and Servers Research
Tieline: 457-1853
External: 408-927-1853 
From: 
<david.black at emc.com> 
To: 
<gliderj at almaden.ibm.com>, <t10 at t10.org> 
Date: 
04/21/2011 02:43 PM 
Subject: 
RE: Question about ROD token "well-known" type 
Sent by: 
owner-t10 at t10.org
________________________________
There will be a single well-known ROD token type in the next version of
11-080 and 11-059, and the name of this will be changed to reflect exactly
what it is.  The purpose of that predefined ROD token will be to serve as a
source of zeroes for the WRITE USING TOKEN command in 11-059 - to be precise,
when the WRITE USING TOKEN command presents that predefined ROD token as a
source of data, the written user data is all 0’s and the written protection
information, if any, is all F’s. 
Thanks,
--David 
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org <mailto:owner-t10 at t10.org>
] On Behalf Of Joseph Glider
Sent: Thursday, April 21, 2011 5:14 PM
To: t10 at t10.org
Subject: Question about ROD token "well-known" type 
I am wondering about the 'well-known ROD token type' as mentioned on page 4
of the 11-080 proposal. There is no description of how this is used, except
to say this: Editor’s Note: First two bytes of the type currently indicate
the token format, except for FF which is for exceptions. For the well-known
SBC-3 tokens, see 11-059. 
But I can't find any mention of this in the 11-059 doc. 
Can somebody point me in the right direction? 
Jody Glider
STSM, Storage Systems and Servers Research
Tieline: 457-1853
External: 408-927-1853 



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