Quantum ATL SuperLoader ATL, User Manual

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Chapter 2 Messages
Supported SCSI Messages
14 Quantum ATL SuperLoader Software Interface Guide
Command
Complete (00h)
2
The COMMAND COMPLETE message is sent by the SuperLoader
to an initiator to indicate that an I/O process has completed and
that valid status has been sent to the initiator. After successfully
sending this message, the SuperLoader goes to the BUS FREE
phase by releasing the BSY signal. The SuperLoader considers the
message transmission successful when it detects the negation of
ACK for the COMMAND COMPLETE message with the ATN
signal false. If a COMMAND COMPLETE message is received by
the SuperLoader, it is handled as an illegal message: the
SuperLoader returns MESSAGE REJECT and enters its STATUS
phase, reporting CHECK CONDITION with the sense key set to
COMMAND ABORTED.
Disconnect (04h)
2
The DISCONNECT message is sent from the SuperLoader to
inform the initiator that the present connection is going to be
broken, such as the SuperLoader plans to disconnect by releasing
the BSY signal, and a later reconnect will be required to complete
the current I/O process. The message does not cause the initiator
to save the data pointer. After sending the message, the
SuperLoader goes to the BUS FREE phase by releasing the BSY
signal.
The DISCONNECT message can also be sent by the initiator to tell
the SuperLoader to suspend the current phase and disconnect
from the bus. The SuperLoader’s response to and its handling of a
DISCONNECT message are based on when, in the I/O process, the
initiator introduces the DISCONNECT message. Table 7
summarizes the SuperLoader’s response.