Seagate Ultra 160 - Manual (Page 105)

Parallel SCSI Interface Product Manual, Rev. A 91
Table 32: MODIFY BIDIRECTIONAL DATA POINTER message format
4.3.11 NO OPERATION
The NO OPERATION message is sent from an initiator in response to a target’s request for a message when
the initiator does not currently have any other valid message to send.
For example, if the target does not respond to the attention condition until a later phase and at that time the
original message is no longer valid the initiator may send the NO OPERATION message when the target
switches to a MESSAGE OUT phase.
Bit
Byte
7 6 5 4 3 2 1 0
0 EXTENDED MESSAGE (01H)
1 EXTENDED MESSAGE LENGTH (09H)
2 MODIFY BIDIRECTIONAL DATA POINTER (05H)
3 (MSB)
DATA--OUT ARGUMENT
4
5
6 (LSB)
7 (MSB)
DATA--IN ARGUMENT
8
9
10 (LSB)