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SCSI Commands
Quantum DLT 4000 Tape Drive
5-3
NOTES
1.
Relative Addressing is not supported by the tape drive. Therefore,
in all I/O commands, the RelAdr bit must be 0.
2.
RESERVE UNIT and RELEASE UNIT by Logical Unit Number are
supported, as are third-party reservations. Extent reservations are
not supported.
3.
The RECEIVE DIAGNOSTIC RESULTS and SEND DIAGNOSTIC DATA
commands implement vendor-unique pages to test the drive during
the manufacturing process. It is recommended that initiators specify
only the non-page format variants of these commands (PF=0),
except for page 0x40.
4.
The DLT tape drive does not act as an initiator on the SCSI bus.
Therefore, the drive will not 1) generate unsolicited interrupts to
the host, 2) initiate its own SCSI commands, or 3) assert bus reset.
5.
Linked commands are supported.
6.
Untagged queuing is supported.
5.1.1 SCSI Pointers
SCSI architecture provides a set of three pointers (called saved pointers) for
each I/O process. The three pointers are: Command, Status, and Data. When an
I/O process becomes active, the three saved pointers are copied to the initiator
as current pointers. There is only one set of current pointers in the initiator at
one time. The current pointers point to the next command, data, or status byte
to be transferred between the initiator's memory and the drive. The saved and
current pointers reside in the initiator.
The saved command pointer always points to the start of the Command Descriptor
Block for the I/O process. The saved status pointer always points to the start of
the status area of the I/O process. The saved data pointer always points to the
start of the data area until the drive sends a SAVE DATA POINTER message for
the I/O process back to the initiator.
Summary of Contents for DLTtape DLT 4000
Page 1: ...DLT 4000 Tape Drive Product Manual November 10 2003 81 60043 04 ...
Page 5: ...USER MANUAL STATEMENTS FOR CLASS B EQUIPMENT continued ...
Page 6: ......
Page 24: ...About This Manual Quantum DLT 4000 Tape Drive xxiv ...
Page 62: ...Hardware Implementation 2 28 Quantum DLT 4000 Tape Drive ...
Page 100: ...Messages 4 12 Quantum DLT 4000 Tape Drive ...
Page 264: ...SCSI Commands 5 164 Quantum DLT 4000 Tape Drive ...
Page 274: ...Appendix B EEPROM Resident Bugcheck and Event Logs B 6 Quantum DLT 4000 Tape System ...
Page 280: ...Appendix C Updating the Firmware C 6 Quantum DLT 4000 Tape Drive ...
Page 298: ...Index Index 6 Quantum DLT4000 Tape Drive ...
Page 299: ......