Continue Task Message: X'12' (I T); Target Transfer Disable Message : X'13' (I T) - Fujitsu MAN3184 SERIES Specifications

2.3.14

CONTINUE TASK message: X'12' (I T)

The CONTINUE TASK message is sent from the INIT to the TARG to reconnect to a task. This
message shall be sent as one of the messages within the consecutive message out phases sent after
the IDENTIFY message.
Thus the messages within the consecutive message out phases following a selection phase consists
of the IDENTIFY, task attribute (if any), and CONTINUE TASK messages.
The purpose of the CONTINUE TASK message is to distinguish a valid INIT attempt at a
reconnection phase from an incorrect initiator reconnection phase.
If the TARG expects a significant delay before it will be ready to continue processing the
reconnected task, it may attempt to free the SCSI bus by sending a DISCONNECT message to the
INIT. The INIT may reject the disconnection attempt by responding with MESSAGE REJECT
message.
If the CONTINUE TASK message occurs on an initial connection then the TARG shall generate a
bus free phase.
If the CONTINUE TASK message occurs on a subsequent connection then the TARG may either
treat this as a dynamic head-of-queue request or it may reject the message with a MESSAGE
REJECT message.
An INIT that gets rejected should set the attention flag to one and send an ABORT TASK message
on the resulting message out phase. Otherwise, the TARG may treat the connection as an
overlapped command.
The INIT should avoid sending this message to the TARG that have not implemented this message.
Such the TARG may not respond as described in this section. An application client can determine
whether a device server implements this message by examining the TRANDIS bit in the standard
INQUIRY data. The application client shall inform the INIT to use the CONTINUE TASK
message by issuing a TARGET TRANSFER DISABLE link control function in the send SCSI
command phase.
2.3.15

TARGET TRANSFER DISABLE message : X'13' (I T)

The TARGET TRANSFER DISABLE message is sent from an INIT to a TARG to request that
subsequent reconnections for data transfer be done by the INIT instead of the TARG. The TARG
might reconnect for other purposes, but shall not generate any data in phase or data out phase after
a TARG reconnection. SCSI devices that implement this message shall also implement the
CONTINUE TASK message.
This message shall be sent as the last message of the series of consecutive message out phase of an
initial connection. The TARG may continue the task, including any data out phase on the initial
connection, until the TARG would normally disconnect, but the TARG shall not.
Reconnect to transfer data. That is, the TARG shall not generate a data in phase on the initial
connection and the TARG shall not generate any data in or data out phases on any subsequent
TARG reconnection for the task.
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