Proper status for Test Unit Ready Command when in drive is in Idle C or Standby.

Gerry Houlder gerry.houlder at seagate.com
Mon Mar 16 06:36:29 PDT 2015


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1503160_f.htm">HTML-formatted message</a>

Test Unit Ready response while in Idle_c should be GOOD status and drive
remains in Idle_c condition. T10 defined it this way so that an initiator
that occassionally polls with TUR would allow a drive to stay in idle or
standby condition.
On Fri, Mar 13, 2015 at 1:53 PM, Edward Younk <Edward.Younk at hgst.com> wrote:
>  Hi Guys,
>
>
>
>
>
> I have a question on the proper response to a test unit ready when the
> drive is in idle-c, or one of the standby states, and the CCF fields in
> Mode page 0x1A are set to enable check condition on recovery, i.e.
“10b”.
>
>
>
>
>
> For example, assume the following command sequence.
>
>
>
>
>
> Drive initially in Idle_C
>
>
>
> *Command
> Status
>								  Power
State*
>
>
>
> Test Unit Ready						 ???
>
>
>		  Drive remains in Idle-C
>
>
>
> Read Command						      Ck Con
> Not_ready, in process of becoming ready	      Drive goes to
> Active-Wait
>
>
>
> Test Unit Ready						 Ck Con
> Not_ready, in process of becoming ready	      Drive still in
> Active-Wait
>
>
>
> *…..drive recovers to
> Active
> Drive in Active*
>
>
>
> Test Unit Ready						 Good
> Status
> Drive in Active.
>
>
>
> In this case, what should the first Test Unit Ready command return?  If it
> is Good Status, isn’t it kind of strange that the first media access
> command would then return that we are “Not Ready in Process of becoming
> Ready”.  If it is a check condition, what is the Addition Key Code/Qual,
> “Not Ready, Cause not Reportable”.  It seems to me their should be a
“Not
> Ready, In Power Save State” Code/Qual
>
>
>
>
>
> If the CCF Idle field is set to “01b” then the I think the sequence is
> well understood.
>
>
>
>
>
> Drive initially in Idle_C
>
>
>
> *Command
> Status
>								  Power
State*
>
>
>
> Test Unit Ready						Good
> status
> Drive remains in Idle-C
>
>
>
> Read Command						      Queue
> Command
>		  Drive goes to Active-Wait
>
>
>
> *…..drive recovers to
> Active
> Drive in Active*
>
>
>
> Dequeue Read and Execute			  Good
> Status
> Drive in Active
>
>
>
> Test Unit Ready						 Good
> Status
> Drive in Active.
>
>
>
>
>
> Thanks,
>
>
>
> Ed,
>
>
>
>
>



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