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SCSI Commands
5-4
Quantum DLT 7000 Tape System
5.1.2 Command Descriptor Block
An initiator communicates with the drive by sending a 6- or 10-byte Command
Descriptor Block that contains the parameters for the specific command. The
SCSI command's operation code is always the first byte in the Command
Descriptor Block and a control field is the last byte. For some commands, the
Command Descriptor Block is accompanied by a list of parameters sent during
the DATA OUT phase. Figure 5–1 shows the format of a typical 6-byte
Command Descriptor Block. Table 5–2 contains a description of the Command
Descriptor Block fields.
Bit
Byte
7
6
5
4
3
2
1
0
0
Operation Code
1
Logical Unit Number
(LUN)
(MSB)
Logical Block Address
(LBA)
2 - 3
Logical Block Address
(LBA)
(LSB)
4
Transfer Length, Parameter List Length, or Allocation Length
5
Control
NOTE: Unless otherwise specified, all reserved bits indicated in the commands are 0.
Figure 5–1 Typical Command Descriptor Block - Data Format
Summary of Contents for DLTtape DLT 7000
Page 1: ...DLT 7000 Tape System Product Manual November 10 2003 81 60000 06...
Page 5: ...USER MANUAL STATEMENTS FOR CLASS B EQUIPMENT continued...
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Page 38: ...General Description and Specifications 1 14 Quantum DLT 7000 Tape System...
Page 292: ...Appendix C Updating the Firmware C 6 Quantum DLT 7000 Tape System...
Page 310: ...Index Index 6 Quantum DLT 7000 Tape Drive...
Page 311: ......