ORB data rates

PJohansson at aol.com PJohansson at aol.com
Wed Mar 19 20:13:38 PST 1997

* From the SCSI Reflector (scsi at symbios.com), posted by:
* PJohansson at aol.com
In a message dated 97-03-18 14:46:48 EST, Mike Bryan writes:

<<I would like to request that you add information describing the speed at
which ORBs are to be transmitted. Also, the "spd" field definition should
 data transfers to system memory for status blocks.>>

Mike, the next revision of SBP-2 clarifies that the speed at which ORB's are
fetched is equal to the speed at which status blocks are stored----and both
speeds are equal to the received speed code of the write to the
MANAGEMENT_AGENT register that signaled the login ORB.

This was always the intent of the technical discussions in the SBP-2 ad hoc
group, but I agree that it is not clearly stated in the draft. It can be
deduced by virtue of the fact that there is not other 1394 transaction
observed by the target that COULD indicate the speed.

The 'spd' field pertains only to the page table (if present) and the data
buffer described by the ORB. Both the page table and the data buffer are
constrained to be within the same node but this may be different from the
initiator's node (at which the ORB's and the status FIFO's are located).

Thanks for reminding me that this needed to go into the next revision.


Peter Johansson
SBP-2 Technical Editor

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