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Ordered Queue
This attribute specifies that the task shall be accepted into the task set and executed in the order received. All tasks
received earlier shall complete before this task. All tasks received later shall complete after this task, except for tasks
received with Head of Queue attribute.
Untagged
This attribute specifies that the task shall be accepted into the task set according to the rules for an untagged task.
Only one untagged task can exist for each logical unit/Initiator pair. A second untagged task for the same pair is
treated as an overlapped command. SCSI-FCP commands are inherently tagged with the OXID/RXID specified in
the frame header. Therefore, commands sent with the untagged task attribute are handled as if they had the Ordered
Queue attribute.
Note: The uncoupled nature of FCAL makes it impossible for the drive to perform command overlap checking. (See
Section 21.6.3 "Overlapped Commands")
18.4 Task Management functions
Task Management functions allow an Initiator to explicitly control the execution of one or more Tasks. SAM defines the fol-
lowing:
•
Abort Task (Implemented as ABTS BLS)
•
Abort Task Set
•
Reset LUN
•
Clear ACA (not supported)
•
Clear Task Set
•
Target Reset
•
Terminate Task
Note: The following description applies to all Task Management functions except Abort Task, which is described separately in
18.4.1, "Abort Task (Implemented as ABTS BLS)", on page 111.
Task Management functions are transmitted in a new exchange using a T1 FCP_CMND IU (see 18.2.1, "FCP_CMND", on
page 105). The Task Management function flags in the IU specify the required function. If any flag is set, all CDB related
fields of the IU are ignored (FCP_CDB, FCP_DL, the Task Codes and Execution Management fields of FCP_CNTL). Only
one Task Management function flag may be set.
The Target responds to a Task Management function with an I4 FCP_RSP IU (see 18.2.4, "FCP_RSP", on page 107). The
RSP_CODE in the FCP_RSP_INFO field shall be as shown in Table 98 and all other fields shall be zeroes.
Table 98: Task Management function RSP_CODE definitions
Code
Description
00h
No Failure (Function Complete)
04h
Function Rejected
05h
Service Delivery or Target Failure
Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
110
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