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SCSI Commands
Quantum DLT 8000 Tape System
5-5
Table 5–2 Command Descriptor Block — Field Descriptions
Field
Description
Operation Code
The operation code specifies the command being requested. The list
of supported SCSI commands and their operation codes are
contained in Table 5–1.
Logical Unit Number
The Logical Unit Number contains the number of the device being
addressed. It must be set to 0. The Logical Unit Number is ignored if
the Command Descriptor Block is preceded by an IDENTIFY Message.
Logical Block Address
Commands that require additional parameter data specify the length
of the Logical Block Address that is needed. See the specific
command descriptions for more detailed information.
The drive does not support Relative Addressing: it defaults to a value
of 0 which specifies that the Logical Block Address specifies the first
logical block of a range of logical blocks to be operated on by the
command. Relative Addressing indicates a technique used to
determine the next Logical Block Address to be operated on.
Transfer Length
The transfer length field normally specifies the number of blocks to
be transferred between the initiator and the drive. For several
commands, the transfer length indicates the number of bytes (not
blocks) to be sent. For these commands, this field may be identified
by a different name.
Parameter List Length
The Parameter List Length is used to specify the number of bytes sent
during the DATA OUT phase. This field is typically used for
parameters that are sent to a drive (for example, mode, diagnostic,
and log parameters). A parameter list length of 0 indicates that no
data is to be transferred.
Allocation Length
This field specifies the maximum number of bytes that the initiator
has allocated for returning data. The host uses this field to limit the
size of data transfers to its own internal buffer size.
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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