Date:  Feb 27, 1993                      X3T9.2/93-037 rev 0


         To:  X3T9.2 Committee (SCSI)

         From:  George Penokie (IBM)

         Subject:  When to issue SDTR after WDTR

         It not 100% clear in SCSI-2 that anytime a WDTR message is
         issued that it must be followed immediately by a SDTR message.

         I propose that in the SCSI-3 SIP document the following be
         added to make it clear that a SDTR message must follow a WDTR
         message.

         In the section which describes the SDTR message another item
         be added to the list of conditions which leaves the data
         transfer agreement in a indeterminate state.  That item
         should be:  after a WDTR message is sent.

         In the section which describes the WDTR message a statement
         should be added which states:  The any device that initiates
         a WDTR message shall renegotiate SDTR before proceeding to
         a data phase.