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

Edward Younk Edward.Younk at hgst.com
Fri Mar 13 11:53:58 PDT 2015


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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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