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Messages
4-6
Quantum DLT 8000 Tape System
4.2.4 DISCONNECT Message (04h)
The DISCONNECT message is sent from the drive to inform the initiator that the
present connection is going to be broken (the drive 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 drive goes to the BUS FREE phase by releasing the BSY signal.
The DISCONNECT message can also be sent by the initiator to tell the drive to suspend
the current phase and disconnect from the bus. The drive’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 4–4 summarizes the drive’s response.
Table 4–4 Drive Response to DISCONNECT Message
BUS Phase
Drive Response
SELECTION
The drive discards the DISCONNECT message and goes to BUS FREE.
COMMAND
The drive discards the DISCONNECT message and goes to BUS FREE. The
ATTENTION request is ignored while the Command Descriptor Block is
fetched. The drive does not switch to MESSAGE OUT until the current DMA
completes.
DATA
The ATTENTION request is ignored while the current data transfer
completes; that is, the drive does not switch to MESSAGE OUT until after
the current DMA completes. The drive returns a MESSAGE REJECT message
and responds with CHECK CONDITION status, indicating the command
aborted because of an invalid message.
STATUS
The drive sends a MESSAGE REJECT message, then sends COMMAND
COMPLETE.
MESSAGE IN
The drive sends a MESSAGE REJECT message and switches to the BUS FREE
phase.
Summary of Contents for DLTtape DLT 8000
Page 1: ...DLTTM 8000 Tape System Product Manual Nov 10 2003 81 60118 06...
Page 5: ...USER MANUAL STATEMENTS FOR CLASS B EQUIPMENT continued...
Page 6: ......
Page 26: ...Table of Contents xxiv Quantum DLT 8000 Tape System...
Page 36: ...About This Manual Quantum DLT 8000 Tape System xxxii...
Page 54: ...General Description and Specifications 1 18 Quantum DLT 8000 Tape System...
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Page 376: ...Appendix A Definition of Vendor Unique Sense Data Information A 4 Quantum DLT 8000 Tape System...
Page 386: ...Appendix C Updating the Firmware C 6 Quantum DLT 8000 Tape System...
Page 396: ...Appendix E Visual Inspection Procedure for DLTtape Cartridges E 8 Quantum DLT 8000 Tape System...
Page 406: ...Appendix G DLT 7000 Emulation Feature G 8 Quantum DLT 8000 Tape System...
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