Remove AIP from SPI-4?

Elliott, Robert Robert.Elliott at
Tue Jun 26 06:54:35 PDT 2001

* From the T10 Reflector (t10 at, posted by:
* "Elliott, Robert" <Robert.Elliott at>
With the industry implementing packetized protocol (information
units) in Ultra 320, I propose that we remove AIP (Asynchronous
Information Protection) from SPI-4.  AIP was a temporary measure
designed for Ultra 160 devices that lacked packetized protocol
support (all of them), which protects the command and status
information under a CRC.  Due to the swift introduction of
Ultra 320, AIP for Ultra 160 has not seen much use in the
industry. Once packetized protocol is implemented, it can be
used at 160 MB/sec or slower speeds, negating the need to 
ever use AIP.

Removing the informative annex describing it in SPI-4 doesn't
preclude AIP from being implemented based on SPI-3.

Rob Elliott, Compaq Server Storage
Robert.Elliott at

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