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18.4.1 Abort Task (Implemented as ABTS BLS)
The Abort Task function is performed using the FC-PH link management functions. Specifically, the Abort Sequence (ABTS)
Basic Link Service (BLS). Refer to 17.2.1, "Abort sequence (ABTS)", on page 57 for a detailed description of this BLS.
Abort Task causes the Target to abort the specified task, if it exists. Previously established conditions such as Mode parameters
and reservations are not affected.
The Initiator performs the Abort Task by using the FC-PH Recovery Abort Protocol. This protocol recovers any resources
associated with the exchange that is being terminated.
The Initiator shall also use the recovery abort protocol for each open exchange following receipt of an FCP_RSP with a
RSP_CODE of No Failure (Function Complete) to Abort Task Set, Clear Task Set, or Target Reset Task Management function.
The recovery abort protocol is as follows:
•
The Initiator generates an ABTS sequence. This may be done regardless of whether or not the Initiator has sequence
initiative. In the ABTS frame:
- SEQ_ID is set to the SEQ_ID of an open sequence at the Initiator. If no sequence is open, any SEQ_ID not cur-
rently in use between the Initiator and the Target may be used.
- SEQ_CNT is set to one more than the SEQ_CNT of the last frame transmitted in the open sequence. If no
sequence is open, SEQ_CNT is zero.
- OX_ID is set to the OX_ID assigned by the Initiator to the task that is being aborted.
- RX_ID is set to FFFFh if no FCP_XFR_RDY (WRITE) or READ data (READ) has been received from the Target.
Otherwise, RX_ID is set to the RX_ID assigned by the Target to the task that is being aborted.
- F_CTL is set for Sequence Context = Initiator.
•
The Target may reject the ABTS with a BA_RJT frame only if
1. the Target has assigned an RX_ID to an OX_ID in a previous frame, and
2. the ABTS has an unknown OX_ID/RX_ID combination.
The reason code in the BA_RJT is Logical error and the reason code explanation is Invalid OX_ID-RX_ID combina-
tion. The F_CTL field is set to indicate that this is the last frame of the exchange.
•
The target accepts the ABTS with a BA_ACC frame. In the frame header:
- OX_ID is set from the OX_ID in the ABTS
- RX_ID is set from the RX_ID in the ABTS
- F_CTL is set to indicate that this is the last frame of the exchange (L_S = 1b) and Sequence Context =Recipient.
In the frame payload:
- SEQ_ID Validity is set to 00h
- SEQ_ID is ignored by the recipient and may therefore be any value
- OX_ID is set from the OX_ID in the ABTS
- RX_ID is set from the RX_ID in the ABTS
- Low SEQ_CNT is set to 0000h
- High SEQ_CNT is set to FFFFh
18.4.2 Abort Task Set
Abort Task Set causes the Target to abort all tasks in the task set that were created by the Initiator. The action is equivalent to
receiving a series of Abort Task requests. Previously established conditions such as Mode parameters and reservations are not
affected.
Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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