Seagate Ultra 320 - Manual (Page 118)

104 Parallel SCSI Interface Product Manual, Rev. A
4.4.3 HEAD OF QUEUE
See Table 42 for the format of the Head of Queue message.
Table 42: Head of Queue message format
The Head of Queue message specifies that the task shall be placed in the task set as a Head of Queue task.
The rules used by the device server to handle Head of Queue tasks within a task set are defined in Section 7.0
of this manual and in the SCSI Architecture Model-2 standard.
4.4.4 ORDERED
See Table 43 for the format of the Ordered message.
Table 43: Ordered message format
The Ordered message specifies that the task shall be placed in the task set as an Ordered task. The rules
used by the task manager to handle Ordered tasks within a task set are defined in Section 7.0 of this manual
and in the SCSI Architecture Model-2 standard.
4.4.5 SIMPLE
See Table 44 for the format of the Simple message.
Table 44: Simple message format
The Simple message specifies that the task shall be placed in the task set as a Simple task. The rules used by
the task manager to handle Simple tasks within a task set are defined in Section 7.0 of this manual and in the
SCSI Architecture Model-2 standard.
Bit
Byte
7 6 5 4 3 2 1 0
0 MESSAGE CODE (21h)
1 TAG (00h-FFh)
Bit
Byte
7 6 5 4 3 2 1 0
0 MESSAGE CODE (22h)
1 TAG (00h-FFh)
Bit
Byte
7 6 5 4 3 2 1 0
0 MESSAGE CODE (20h)
1 TAG (00h-FFh)