Subject: RE: Redundant primitive sequences Date: Tue, 28 Feb 2006 13:29:31 -0600 From: "Elliott, Robert (Server Storage)" <Elliott@hp.com> To: <t10@t10.org> X-Message-Number: 6679 Formatted message: HTML-formatted message The figure is showing when the receiver detects the primitive sequence under a variety of different scenarios (but not every possible scenario). If a transmitter sends more than 6, they'll still just be decoded as part of one primitive sequence. There are so few redundant primitives - BREAK, BROADCAST, and HARD_RESET - that some of the details are not important. After HARD_RESET, nothing else matters. After BREAK, another BREAK has no effect. Identical BROADCASTs are already subject to being combined by expanders, so whether you decode 1 or two makes no difference. If you're testing a transmitter, I'd flag it as a bug if it sent more than 6 because there is no benefit from doing so and it was probably not intended by the designer. In a real system, though, receivers won't mind. -- Rob Elliott, elliott@hp.com Hewlett-Packard Industry Standard Server Storage Advanced Technology https://ecardfile.com/id/RobElliott ________________________________ From: Yamini [mailto:Yamini@medusalabs.com] Sent: Tuesday, February 07, 2006 10:40 PM To: t10@t10.org; Elliott, Robert (Server Storage) Subject: Redundant primitive sequences Hello, I have a question about Primitive Sequences. The number of primitives that a sender can send in a Redundant Primitive Sequence is not clearly mentioned in the spec. I hope someone from the reflector can clarify this for me. 'Figure 131 - redundant primitive sequence' in SAS spec 2.0(sas2r00.pdf) shows 10 back to back Primitives in a redundant sequence. Is this legal? The reason why ask is that the text preceeding this figure says: " 7.2.4.6 Redundant primitive sequence Primitives that form redundant primitive sequences (e.g., BROADCAST (CHANGE)) shall be sent six times consecutively. ALIGNs and NOTIFYs may be sent inside primitive sequences as described in 7.2.4.1. A receiver shall detect a redundant primitive sequence after the identical primitive is received in three consecutive dwords. After receiving a redundant primitive sequence, a receiver shall not detect a second instance of the same redundant primitive sequence until it has received six consecutive dwords that are not any of the following: a) the original primitive; or b) an ALIGN or NOTIFY." I interpret it as the sender SHALL only send six consecutive primitives. So is sending more than 6 primitives in a redundant sequence an error? Also, is sending sequences without a six dword gap in between sequences legal? The above section from the spec states clearly about the receiver's requirements but not the sender's side. Thanks in advance, Yamini Thanks, Yamini