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There are a few areas related to CONT that could be clarified in Volume 3. Referencing ata7v3r3c... 1. In section 15.4.2 (Primitive descriptions), table 21 lists CONT as having "Single" usage rather than "Repeated." However, I believe these patterns (among others) are intended to be legal (and some of them do show up in SATA devices today): a) <prim> <prim> CONT CONT <dw> <dw> ... b) <prim> <prim> CONT CONT CONT ... <dw> <dw> ... c) <prim> <prim> CONT <dw> CONT <dw> <dw> ... d) <prim> <prim> CONT <dw> <dw> ... CONT <dw> <dw> ... Example b) is not very good for EMI, but the receiver should still accept it. Pairs of ALIGNs could appear anywhere during these patterns. One way to clarify that these are allowed would be to label CONT as "Repeated" rather than "Single." This means the second CONT would repeat the previous CONT (which repeats the previous primitive, which could also be a CONT). Another approach is to leave it "Single", but redefine it as repeating the previous primitive that was not CONT or ALIGN, rather than just repeating the previous primitive. For example, this sentence in table 21: "The CONT primitive implies that the previously received primitive be repeated as long as another primitive is not received." should change to: "The CONT primitive implies that the previously received primitive <that was not a CONT or ALIGN primitive> be repeated as long as another primitive <other than ALIGN> is not received." (some similar rewording may be appropriate in 15.4.5) 2. Section 15.4.5 CONT (primitive) section discusses the importance of this feature for EMI reduction, but then says "The transmission of a CONT primitive is optional, but the ability to receive and properly process the CONT primitive is required." Shouldn't transmission of CONT also be mandatory? Left optional, a system accepting arbitrary devices and controllers has to be designed assuming that it is never used and cannot benefit from the alleged EMI reduction. 3. For standardese completeness, what is the meaning if CONT is the very first primitive received after the ALIGNs in speed negotiation? It should be illegal to transmit it at that time. If a receiver sees it at that time, perhaps it should treat it as if a SYNC were received? -- Rob Elliott, [EMAIL PROTECTED] Hewlett-Packard Industry Standard Server Storage Advanced Technology https://ecardfile.com/id/RobElliott
