Target initiated synchronous negotiation.

scheible at VNET.IBM.COM scheible at VNET.IBM.COM
Thu Jun 1 08:56:08 PDT 1995

Rick Roche wrote...
>>  We are revisiting the initiate negotiation question on our disk
>>  products and we wanted to query the reflector audience for their
>>  input.
>>  Currently, we DO NOT initiate synchronous negotiation since some
>>  early host adapters didn't respond very well to the behavior.  One
>>  concern with this behavior is an adapter which doesn't re-negotiate on
>>  check conditions status may result in a sync host with and Async target.
>>  We do allow for target initiated negotiations to be enabled through
>>  a mode page control bit, but it's defaulted off.
>>  One proposal is to turn initiate on for wide negotiations based on
>>  the argument that most (all?) wide adapters must be more advanced
>>  and probably handle target initiated negotiations fine.  Is this
>>  a reasonable assumption?  Do people know of drives which do initiate
>>  negotiations by default?
>>  Comments?

   IBM high end disk drives can either use or block target initiated
synchronous negotiation.  The control is via an option block pin, and
can be sensed via a vendor unique mode page flag.  Whatever the customer
wants, he gets.

John Scheible
scheible at

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