SBC-3 comment for Next T10 meeting

John Geldman (jgeldman) jgeldman at micron.com
Wed Apr 24 15:10:11 PDT 2013


* From the T10 Reflector (t10 at t10.org), posted by:
* "John Geldman (jgeldman)" <jgeldman at micron.com>
*
Fred,
I too agree with your central point that the CAP correction was flawed.
But your suggested text suggests that low power allows a non-volatile cache
to transform into a volatile cache. That would be a strange causality, not
well based in physics. Low power detection is more of a signal to the device
server that leads to an action from the device server.
We could go back (as you suggested), or how about:
The power, if any, that allows a non-volatile cache to remain non-volatile
may become low enough (e.g., the battery voltage becomes too low to sustain
cache contents beyond a vendor specific time) such that the device server
converts the non-volatile cache into a volatile cache for a vendor specific
minimum time.
John Geldman
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Gerry Hould=
er
Sent: Wednesday, April 24, 2013 1:20 PM
Cc: t10 at t10.org
Subject: Re: SBC-3 comment for Next T10 meeting
Yes, i agree that Fred's proposed wording retains the original meaning of
this sentence, while the change made in the last CAP meeting does not.
On Wed, Apr 24, 2013 at 1:42 PM, Knight, Frederick
<Frederick.Knight at netapp.com> wrote:
During LB comment resolution in Vancouver, it appears that the following
change was made:
4.15 Caches
<...>
The power, if any, that allows a non-volatile cache to remain non-volatile
may become low enough to prevent
the non-volatile cache from remaining non-becoming volatile for a vendor
specific minimum time (e.g., the
battery voltage becomes too low too sustain cache contents beyond a vendor
specific time). If this occurs and
Old text: ... prevent the NV cache from remaining non-volatile .. [ means
allowing it to become volatile ]
New text: ... prevent the NV cache from becoming volatile ... [ means
preventing it from becoming volatile ]
The original text describes low power preventing the cache from staying
non-volatile [i.e., allowing the cache to become volatile].  NOW, the new
text describes that low power will prevent the cache from becoming volatile.
The new text is not correct.  The text should be restored or changed to
something like:
The power, if any, that allows a non-volatile cache to remain non-volatile
may become low enough to prevent
the non-volatile cache from remaining non-becoming allow the non-volatile
cache to become volatile for a vendor specific minimum time (e.g., the
battery voltage becomes too low too sustain cache contents beyond a vendor
specific time).
Since CAP made this change in the first place, the wording to fix it needs to
go before CAP too.
		Fred
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