X3T9.2/90-117





August 24, 1990

Mr. Brian Earle, Project Engineer
Eventide, Inc.
1 Alsan Way
Little Ferry, NJ 07643

Subject:  Request for Interpretation, #2 on X3.131-199X, SCSI-2

Dear Mr. Earle,

Your Request for Interpretation (#2) on X3.131-1990, Small Computer System 
Interface (SCSI-2), concerning whether filemarks and setmarks should be 
assigned block addresses (identifiers) when using the LOCATE and READ POSITION 
commands has been considered by Task Group X3T9.2 and by Technical Committee 
X3T9.  It is the conclusion of these groups that filemarks and setmarks are to 
be assigned identifiers for this purpose.

This opinion is based on the contents of section 9.1.6.  In particular, the 
sentence that you quoted in your request says:

  "Filemarks and setmarks may or may not have recorded identifiers, but if 
  identifiers are used in the format, then each mark is assigned a value even 
  if it is not explicitly recorded."

Since SCSI-2 has not been published yet, X3T9.2 is recommending that a 
reference to section 9.1.6 be added to the descriptions of block addresses in 
the sections on the LOCATE and READ POSITION commands during the publication 
of SCSI-2.  This may help implementors in the future to avoid the error you 
have encountered in some DAT implementations.

Thank you for bringing this matter to our attention.

Sincerely,



Del Shoemaker, Chairman X3T9


cc:  Lynn Barra, Coordinator, Nat'l Stds. Processing, X3
     John Lohmeyer, Chairman X3T9.2