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Command Processing
(1) HARD RESET
HARD RESET is used to abort all commands and to initialize the IDD to restore
it to the same state as at the time of power-on.
After this reset operation, the UNIT ATTENTION condition with SCSI Reset
Occurred [= 06-29-02] is generated for all the INITs.
(2) LOGICAL UNIT RESET
LOGICAL UNIT RESET TASK can be used to abort an L nexus command
specified by an INIT and to initialize TARG to restore it to the same state as at the
time of power-on. However, it must be noted that commands that have been
issued by other initiators are also cleared in a multi-initiator environment.
After this task is performed, the unit attention condition for Target Reset Function
Occurred [= 06-29-03] is generated for all the INITs.
(3) CLEAR TASK SET
CLEAR TASK SET is used to abort processing of the L nexus commands
specified by an INIT. Environment settings and conditions, such as MODE
SELECT parameters, that have been specified in advance are not changed.
After this task is performed, the unit attention condition for Command Cleared by
Another INIT [= 06-2F-00] is generated for the INITs whose commands have
been subject to abortion except for the INIT that has issued this task.
(4) ABORT TASK SET
ABORT TASK SET is used to abort the I-T-L nexus commands specified by an
INIT.
(5) ABORT TASK
ABORT TASK is used to abort processing of the I-T-L-Q nexus command
specified by an INIT.
•
Abort processing during write operation
In particular, if a command to write data to the disk medium which is currently
being executed is cleared, the IDD aborts processing of that command as shown
in Table 2.10. Stopping overlapped commands which are currently being executed
(see 2.8.1) is accomplished by the same treatment. The INIT must investigate the
command completion status, then if necessary, it must implement data recovery
processing.
2-18
C141-C009
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