Response to Overlapped Commands Questions

George Penokie GOP at
Thu Mar 9 19:30:27 PST 1995


In response to your SCSI-2 questions:

1.  What is supposed to happen with the Tag 0E command?  That is, when
the drive clears its queue, is it when it detects the error (parsing
the second 0C command) or when it reports the check condition (after
receiving the 0E command)?

Response:  What happens to the Tag 0E command depends on the internal
workings of the drive.  If the tag 0E command is in the queue when the
overlapped error is detected then it should be cleared along with any
other commands in the queue.  The actual point of detection of the
overlapped error is implementation specific.

2.  According to the SCSI-2 spec, "if a target receives a queue tag
that is currently in use for the I_T_L nexus, it shall respond as
defined in 7.5.2".  (section 6.6.17).

Does this imply that a target is responsible for validating the tag ID
before disconnecting, to prevent the condition described above?

Response: There is no requirement that the target validate the tag ID
before disconnecting.

Bye for now,

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