Quantum DLTtape DLT1, Interface Manual

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DLT1/VS80 SCSI Interface Guide
81-81276-01 Rev A01 July 2004 3-3
3.2.2 BUS DEVICE RESET (0Ch)
This message from an initiator clears all commands, data, and status in the tape drive controller. When
the tape drive recognizes this message, it writes cached data to the medium and goes to the BUS FREE
phase. The tape drive then executes a hard reset, which leaves it as if a BUS RESET had occurred.
3.2.3 COMMAND COMPLETE (00h)
A target sends this message to an initiator to indicate that it has completed the execution of a command
or a series of linked commands and has sent valid status to the initiator. After successfully sending this
message, the target goes to the BUS FREE phase by releasing BSY.
If the tape drive receives this message, it handles it as an illegal message. The tape drive returns
MESSAGE REJECT and enters the STATUS phase reporting CHECK CONDITION with the Sense
Key set to COMMAND ABORTED.
3.2.4 DISCONNECT (04h)
A target sends DISCONNECT to tell an initiator that the target intends to break the present physical
path; that is, the target intends to disconnect by releasing BSY. Later, the initiator must reselect the
target in order to complete the current operation. This message does not cause the initiator to save the
data pointer.
When it receives this message from an initiator, the tape drive can respond in one of two ways.
1. It can take the message as a request by the initiator to disconnect and comply by entering the
MESSAGE IN phase and returning the DISCONNECT message to the initiator, possibly preceded
by the SAVE DATA POINTERS message. In this case, it delays a minimum of 200 ms before
arbitrating for the bus again.
2. It can enter the MESSAGE IN phase and return MESSAGE REJECT EXTENDED MESSAGE
(01h).