Quantum DLT 8000 Tape System
4-1
Chapter 4
MESSAGES
The SCSI message system allows communication between an initiator and the drive for
interface management and command qualification. Messages can be originated by
either the initiator or the drive. This section contains a detailed description of the
messages supported by the disk drives.
4.1
Message Format
A message can be one or more bytes in length. One or more messages can be sent during
a single MESSAGE phase, but a message cannot be split over MESSAGE phases. The
initiator is required to end the MESSAGE OUT phase (by negating ATN) when it sends
certain messages that are identified in Table 4–2.
When a connection to the drive is established (i.e., the drive is selected with ATN
asserted), the first message byte passed by the initiator must be either an IDENTIFY,
ABORT, or BUS DEVICE RESET message. If not, the drive discards the message, saves
no status information, and goes to the BUS FREE phase.
If an initiator supplies an unsupported message (for example, COMMAND COMPLETE
or a reserved or undefined message code), the drive returns a MESSAGE REJECT
message and continues where it left off (possibly returning to MESSAGE OUT if ATN is
raised).
The first byte of the message, as defined in Table 4–1, determines the format of the
message.
Table 4–1 Message Format
Message Code
Message
00h
One-byte message (COMMAND COMPLETE)
01h
Extended message
02h – 1Fh
One-byte message
20h – 2Fh
Two-byte message
40h – 7Fh
Reserved
80h – FFh
One-byte message (IDENTIFY)
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...
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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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