Date: Mar 22, 1991                            X3T9.2/91-034 Rev 1


 To: X3T9.2 Committee (SCSI)

 From: George Penokie (IBM)

 Subject: Response to X3T9.2/90-173 Document


 Proposal:

 On reviewing HP's 90-173 document I am in agreement that some wording
 changes should be made to the SCSI-2 document to make it clear that
 multiple active I/O processes are allowed in the standard.  I propose
 that the following changes be added to SCSI-2.

 1-Page 5-20, Section 5.6.1, Paragraph 1, Sentence 1:
   Change the statement 'the active I/O process' to 'any active I/O
   processes'.
   Last Sentence:
   Change the statement 'queued I/O process' to 'I/O processes'.

 2-Page 5-21, Section 5.6.2, Paragraph 1: Response to 90-173 comment
   no change required:  The I/O processes pointed to by the tag is the
   only one affected this is in the definition of the current I/O
   process.

 3-Page 5-31, Section 5.6.22 Paragraph 1, Sentence last:
   Change 'queued or executing I/O processes' to 'I/O processes'.

 4-Page 5-32, Section 5.6.22 :

   Entire section reworded see SCSI-2 Rev 10d.

 5-Page 6-16, Section 6.6, Paragraph 2, Sentence last:
   Change 'Execution of queued commands for the' to 'Execution of all
   tagged I/O processes'.

 6-Page 6-16, Section 6.7, Paragraph 2, Sentence 2:
   Change 'Execution of queued commands for the' to 'Execution of all
   tagged I/O processes'.

 7-Page 6-17, Section 6.8, Paragraph 1, Sentence 2: Response to 90-173
   no change required: The standard does not address what later is so
   it does not preclude one I/O process starting while another is still
   executing.

 8-Page 6-17, Section 6.8.1, Paragraph 1, Sentence 1:
   Change 'while a command from another initiator is being executed' to
   'while I/O processes from other initiators are being executed.'

 9-Page 6-17, Section 6.8.1, Paragraph 2, Sentence 2:
   Change 'the new I/O process, the target may either suspend the active
   I/O process or it may return BUSY status to the new I/O process.' to
   'the current I/O process, the target may either suspend all other
   I/O processes or it may return BUSY status to the current I/O
   process.'

10-Page 6-18, Section 6.8.2, Paragraphs 2,4,6: Response to 90-173 no
   change required:  The order is not disturbed in with multiple active
   I/O processes as far as the initiator is concerned in that the start
   of execution is ordered and the end is ordered.

11-Page 6-19, Section 6.8.2, Paragraph 5, Sentence 3:
   Change the statement 'commands in the queue' to 'all I/O processes'.

12-Page 6-19, Section 6.8.2, Paragraph 7, Sentence 1:
   Change 'clears the queue' to 'aborts all I/O processes'.

   Sentence 2: Remove the statement 'When the queue is cleared because
   of this recovery option'.

13-Page 7-79, Section 7.3.3, Paragraph 4:
   Change to 'A queue error management (QErr) bit of zero specifies
   remaining suspended I/O processes shall resume after the contingent
   allegiance or extended contingent allegiance (see 6.8).

   A QErr bit of one specifies all remaining suspended I/O processes
   shall be aborted after the contingent allegiance or extended
   contingent allegiance (see 6.8).  A unit attention condition shall be
   generated for each initiator that had a suspended I/O process aborted
   except for the initiator which had the condition allegiance or
   extended contingent allegiance.  The target shall set the additional
   sense code to TAGGED COMMANDS CLEARED BY ANOTHER INITIATOR.'

14-Page 7-79, Section 7.3.3, Paragraph 4, Sentence 2:
   See number 13.

15-Page E-1 - E-5, Section E.1 :  Response to 90-173 no change required:
   The appendix is only an example of one way to do things and does not
   preclude multiple active I/O processes.