Message Codes; Command Complete Message In; Extended Message; Save Data Pointers In - Sun Microsystems storagetek sl500 Reference Manual
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Message System
Message Codes
The following paragraphs explain the messages in
TABLE 3-4 on page
24.
Command Complete Message In
The library sends the Command Complete message (00) to the initiator to indicate
that the execution of the command has completed and that valid status has been
sent to the initiator.
Extended Message
The initiator might try to negotiate wide or synchronous transfers. The library
accepts these negotiations but always negotiates to narrow and asynchronous
transfers.
Save Data Pointers In
The library sends the Save Data Pointers message (02) to tell an initiator to save a
copy of the active data pointer for the library. The library sends this message before
sending the Disconnect message.
Restore Pointers Message In
The library sends the Restore Pointers message (03) to direct an initiator to restore
the most recently saved command, data, and status pointers for the active I/O
process. The message is sent after receiving an Initiator Detected Error message or
Parity error during a transfer which can be retried. The transfer is then restarted.
Disconnect Message In
The library sends the Disconnect message (04) to inform an initiator that the
present connection is going to be broken and that a later reconnect is required to
complete the current command. After successfully sending this message, the
library enters the Bus Free phase.
Initiator Detected Error Out
An initiator sends the Initiator Detected Error message (05) to inform the library
that the initiator has detected an error. Depending on the active phase, the library
aborts the current I/O, sends a Message Reject, or issues a Restore Pointers, and
restarts the transfer.
Abort Out
An initiator sends the Abort message (06) to the library to halt a process. If an
I_T_L nexus is established, any pending data and status is cleared and the process
is aborted; otherwise, no action is taken.
96122 • Revision: F
Chapter 3 SCSI Bus Operations 25
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