From: David Peterson
Sent: Friday, August 25, 2006 1:52 PM
To: 'BANTHER,MICHAEL (HP-UnitedKingdom,ex2)'; 'Erich Oetting'; 'Greg Wheeless'; 'Kevin Butt (kdbutt@us.ibm.com)'; 'Paul Entzel (paul.entzel@quantum.com)'; 'Paul Suhler (paul.suhler@quantum.com)'
Subject: FCP-4: Sequence count to zero on retriesHowdy,Forgot to mention the other action item I had for FCP-4. From the minutes:5.2 Continuously Increasing Sequence Count
It was requested at a prior meeting that FCP-4 require use of Continuously Increasing Sequence Count for unacknowledged classes of service (i.e., Class 3).
Dave reported status on his action item to prepare a proposal. He has studied the issue and is not yet convinced that the value justifies the possible impact on implementations. He will be posting the question to the T10 and T11 reflectors.
It was noted that this requirement had been rejected historically, but that more recent FC-4 protocols require it.
Dave also directed the group to an inconsistency in FCP on the maintenance of the Sequence Count in the event of Sequence retry with CISC. He asked the community whether the Sequence Count “may” or “shall” restart at zero for the retry. See FCP-4 subclauses 8.2, 12.4.1.6, and 12.4.1.7 for the inconsistent statements.
ACTION: Dave Peterson to contact tape vendors to see whether they are able to force the Sequence Count to zero on Sequence retries.
So again, what say ye?From FCP-4 Rev 00:5.2 Continuously Increasing Sequence Count
For unacknowledged classes, the Sequence Count for a retransmitted FCP_DATA IU shall start at zero, even if continuously increasing sequence count is being used.
12.4.1.6 FCP_DATA IU recovery - write operations
For unacknowledged classes, the SEQ_CNT field value may start at zero, even if continuously increasing sequence count is being used.12.4.1.7 FCP_DATA IU recovery - read operations
For unacknowledged classes, the SEQ_CNT field value may start at zero, even if continuously increasing sequence count is being used.
Also, does anyone, other than HP who has already replied indicating support, have an opinion whether continuously increasing sequence be required?Thanks...Dave(no disclaimer)