SAS-1.1 Task Frame

Larry Chen Larry_Chen at pmc-sierra.com
Mon Mar 26 15:10:52 PDT 2007


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See my comments inline in RED.
SAS-1.1 Rev 10
---------------------------------
Taken from page 348:
The TAG field contains a value that allows the SSP initiator port to
establish a context for commands and task
management functions.
For COMMAND frames and TASK frames, the SSP initiator port shall set the TAG
field to a value that is unique
for the I_T nexus established by the connection (see 7.12). An SSP initiator
port shall not reuse the same tag
when transmitting COMMAND frames or TASK frames to different LUNs in the same
SSP target port. An SSP
initiator port may reuse a tag when transmitting frames to different SSP
target ports. The TAG field in a
COMMAND frame contains the task tag defined in SAM-3. The TAG field in a TASK
frame does not
correspond to a SAM-3 task tag, but corresponds to an SAM-3 association (see
10.2.1). The tag space used
in the TAG fields is shared across COMMAND frames and TASK frames (e.g., if a
tag is used for a COMMAND
frame, it is not also used for a concurrent TASK frame).
[comment #1: The TAG field in the TASK frame does not correspond to a SAM-3
task tag, but corresponds to
an SAM-3 association (see 10.2.1).
This seems odd and contradicts everything I know about Q Tags. Also, SAM-3
does not mention about association
i.e., SAS-1.1 association instead.
]
---------------------------------
Taken from page 415:
Task Management Request Received (IN (Nexus, Function Identifier,
[Association]))
[comment #2: Association is optional.
If Association == TAG OF TASK TO BE MANAGED field then this would make sense
since
TAG FO TASK TO BE MANAGED is only meaningful for ABORT_TASK and QUERY_TASK.
]
Taken from Table 161 on page 416:
Nexus
I_T_L nexus or I_T_L_Q nexus (depending on the Function Identifier), where:
a) I indicates the initiator port that sent the TASK frame;
b) T indicates the target port that received the TASK frame;
c) L indicated by the LOGICAL UNIT NUMBER field in the TASK frame header; and
d) Q (for an I_T_L_Q nexus) indicated by the TAG OF TASK TO BE MANAGED field
in
the TASK frame header.
[Association] Indicates the TAG field in the TASK frame header.
[Comment #3: d) Q (for an I_T_l_Q nexus indicated by the TAG OF TASK TO BE
MANAGED field
In the TASK frame header.
Should this be revised to ... ?
indicated by the TAG field in the TASK frame header.
].
[Comment #4: [Association] Indicates the TAG field in the TASK frame header.
Should this be revised to ...?
[Association] Indicates the TAG OF TASK OT BE MANAGED field in the TASK
frame.
]



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