Question on Synchronous data transfer

Eshwar Parigi eshwar at
Sat Mar 2 10:53:34 PST 1996

* From the SCSI Reflector, posted by:
* eshwar at (Eshwar Parigi)


I am trying to implement SCSI Initiator and Target models and
came across the following situation, I would appreciate if someone
can answer my questions. Thanks in advance.

Thank You,


Xfer parameters:

Synchronous xfer of 7 bytes, data_in_phase, offset of 3.


   TR1 TR2 TR3 ....TR4  TR5  TR6  ... TR7

            IA1 IA2 IA3 ...... IA4 IA5 IA6..............  ?????

   Where TR1 - TR7 are Target REQ's 1 to 7
         IA1 - IA7 are Initiator ACK's  1 to 7
   Question: Since the offset of 3 was agreed upon and the Initiator
             is waiting for 3 REQ's to happen before it can issue
             ACK's but there is only one byte to be xfered. In this
             case, what should be the behavior of the Initiator?

2. Its the same situation as above except that the xfer count is 20.
   But, the target has stopped issuing TR8 and is waiting for IA7, 
   because it has hit a Memory boundary and is waiting for the present
   address boundary to be over before it can access the next address
   boundary. Can this happen? If so, how to handle to this. 

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