Ignore Wide Residue Message: X'23' (T→I) - Fujitsu MBA3073 SERIES Technical Manual

If the TARG reconnects to the INIT to continue a tagged I/O operation, the TARG sends the
SIMPLE message immediately after the IDENTIFY message in the reconnection sequence of the
same MESSAGE IN phase.
(1) SIMPLE message: X'20'(I↔T)
The SIMPLE message specifies that the task be placed in that logical unit's queue. The order of
execution is determined by the HDD.
(2) HEAD OF QUEUE message: X'21'(I→T)
The HEAD OF QUEUE message specifies that the task be placed first in that logical unit's
command queue. A subsequent task received with a HEAD OF QUEUE message is placed at the
head of the command queue for execution in last-in, first-out order.
(3) ORDERED message: X'22'(I→T)
The ORDERED message specifies that the task be placed in that logical unit's command queue for
execution in the order received. All queued tasks for the logical unit received prior to this I/O
process are executed before this task is executed. All queued tasks received after this task is
executed after this task, except for tasks received with a HEAD OF QUEUE message.
2.3.18 IGNORE WIDE RESIDUE message: X'23' (T→I)
Bit
7
Byte
0
1
This message the number of bytes of invalid data is notified from TARG to INIT when not
coming up to the width of the data bus which the number of bytes of data which transfers to INIT
by the last REQ/ACK handshake of the DATA IN phase and the REQB/ACKB handshake uses in
the place where the wide data transfer is executed.
When it is necessary to send this message, TARG executes the MESSAGE IN phase without fail
immediately after the end of the DATA IN phase, and transmits this message first.
All the numbers of bytes of data transferred at the end become effective in the place where this
message is not sent.
The number of bytes of data which transferred at the end does not come up to the width of the data
bus in the place where DISCONNECT is done before forwarding all the data specified by the task
(DATA IN phase) ends TARG transmits this message before the SAVE DATA POINTER
message.
166
6 5 4
Message Code (X'23')
Number of bytes to IGNORE (X'01')
3 2 1 0
C141-C015