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Command Processing
1 - 6 C141-E167
1.2 Status Byte
Figure 1.4 shows status byte format and the type of status that the IDD supports.
The status byte is one byte of information sent from the TARG to the INIT in the STATUS phase
when one command is completed, and notifies the INIT of the results of the command’s execution.
The status byte is also sent even in cases when the TARG is in a state which it makes it impossible
for it to execute the command when it receives a request for an input/output operation. However, if
the command is cleared by switching to the BUS FREE phase forcibly through an ABORT TASK
SET message, an ABORT TASK message, a CLEAR TASK SET message, a TARGET RESET
message, a RESET condition or a SCSI bus error state, etc., the status byte for that command is not
reported.
After the TARG reports the status byte in the STATUS phase, it will always send a TASK
COMPLETE message or a LINKED TASK COMPLETE (WITH FLAG) message to notify the INIT
of the validity of the status byte.
Bit 76543210
0 0 Status Byte Code 0
Bit 5 4 3 2 1
0 0 0 0 0 GOOD Status
0 0 0 0 1 CHECK CONDITION Status
0 0 0 1 0 CONDITION MET Status
0 0 1 0 0 BUSY Status
0 1 0 0 0 INTERMEDIATE Status
0 1 0 1 0 INTERMEDIATE CONDITION MET Status
0 1 1 0 0 RESERVATION CONFLICT Status
1 0 0 0 1 COMMAND TERMINATED Status
1 0 1 0 0 QUEUE FULL Status
Figure 1.4 Status byte
(1) GOOD status
This status indicates that execution of the command ended normally.