Status - Seagate SCSI Interface Product Manual

SCSI Interface Product Manual, Rev. J
4.3

Status

A Status byte shall be sent from the target to the initiator during the Status phase at the termination of each
command as specified in Tables 17 and 18 unless the command is cleared by one of the following conditions:
1. an Abort message
2. a Bus Device Reset message
3. a hard reset condition
4. an unexpected Bus Free condition (see Section 3.1.1)
5. an Abort Task message
6. a Clear Task Set message
Table 17: Status byte
Bit 7
Byte
0 Reserved
Table 18: Status byte code bit values
Bits of status byte
7 6 5 4 3
R R 0 0 0
R R 0 0 0
R R 0 0 0
R R 0 0 1
R R 0 1 0
R R 0 1 0
R R 0 1 1
R R 1 0 0
R R 1 0 1
R R 1 1 0
All other codes
Key: R—Reserved bit (must be zero for drive)
[1] What was formerly called a "Command Queue" is now called a "Task Set."
A description of the status byte codes is given below.
Good—This status indicates that the target has successfully completed the task.
Check Condition—Any error, exception, or abnormal condition that causes sense data to be set shall cause a
Check Condition status. An Auto Contingent Allegiance condition has occurred and the Request Sense com-
mand should be issued following a Check Condition status to determine the nature of the condition.
Condition Met—This status shall be returned whenever the requested operation specified by an unlinked
command is satisfied (see the Search Data and Prefetch commands). This status does not break a chain of
linked commands. The logical block address of the logical block that satisfies a search may be determined with
a Request Sense command.
Busy—The target is busy. This status shall be returned whenever a target is unable to process the command
from an otherwise acceptable initiator (i.e., no reservation conflicts). Busy status shall be returned if the initiator
has not granted the disconnect privilege and attempts to queue a command or if the initiator rejects the discon-
nect message and the queue is not empty. Busy status shall also be returned if a Change Definition command
is received requesting that the drive change from SCSI-2 mode to SCSI-1 mode and the queue is not empty, or
if commands from other initiators or tagged commands from the contingent host are received while an Auto
6 5
2 1 0 Status represented
0 0 R Good
0 1 R Check Condition
1 0 R Condition Met/Good
0 0 R Busy
0 0 R Intermediate/Good
1 0 R Intermediate/Condition Met
0 0 R Reservation Conflict
0 1 R Command Terminated
0 0 R Queue Full/Task Set Full [1]
0 0 R ACA Active
Reserved
4 3
Status Byte Code
2 1
Reserved
47
0