Dal Allan Technical Editor BSR X3.170 May 5, 1990 Maxtor Corporation needs some guidance and interpretation of the following items in the ESDI rev 3A document of December 2, 1989. 1) In Table 7 and 8, Command Function 1000b, Initiate Diagnostics, the Yes/No responses appear to be inverted. Table 28, Diagnostic Parameter Bits, does specify a Command Modifier or a Command Subscript. 2) In Table 9, Request Status Modifier Bits, the subscripts column of the 0xxxb Command Modifier is not defined. Is the usage of subscripts allowed? If it is why is the document ambiguous on this? 3) In Table 18, Magnetic Disk Specific Configuration Response Bits, what does Command Modifier 1001b, Bits 7-0, Number of Vendor Unique Status Words refer to? In particular if subscripts are allowed in item 2 above what value should be returned? 4) If subscripts are allowed in 2 and 3 then a method is needed to inform the controller of how many subscripts are supported within each vendor unique status word. One suggestion is to return the number of supported subscripts as a response to subscript 01h being requested. This would be an additional requirement and would have to worded in an implementors note as a suggestion. 5) Section 7.12, paragraph 2, refers to a Command Modifier while in Table 28 a Diagnostic Number is specified. 6) Section 7.12, paragraph 4, implies that all diagnostics are executed if the diagnostic parameter is zero. This seems undesirable, since some of the vendor specific diagnostics can be destructive to the data integrity. Please explain the meaning of this paragraph such that the ambiguity is removed. 7) Section 7.12, where is diagnostic status returned? There is no provision in the standard that I can find for returning diagnostic status. Clarification of the above items would be appreciated. Sincerely, Lawrence J. Lamers Principal Member X3T9.2 cc: John Lohmeyer