SCSI Commands
Quantum DLT 4000 Tape Drive
5-123
READ BUFFER Command (3Ch) (continued)
Table 5–58 READ BUFFER Command Descriptor Block - Field Descriptions
Field Name
Description
Mode
The tape drive supports the following values within this field. If any non-supported
value is set, the drive terminates the command with a CHECK CONDITION status,
ILLEGAL REQUEST sense key set.
Mode
Description
000b
Combined Header and Data (subsection 5.14.1)
010b
Data (subsection 5.14.2)
011b
Descriptor (subsection 5.14.3)
Buffer ID
Must be 0, 1 or 2. If any other value appears in this field, the tape drive returns a
CHECK CONDITION status with ILLEGAL REQUEST sense key set.
Buffer Offset
Not supported; must be 0. If any other value appears in this field, the tape drive
returns a CHECK CONDITION status with ILLEGAL REQUEST sense key set.
Allocation
Length
This field specifies the maximum number of bytes that the initiator has allocated
for returning data.
5.14.1 Combined Header and Data Mode
In this mode, the tape drive returns a 4-byte header followed by data bytes. The
drive terminates the DATA IN phase when the Allocation Length bytes of
header and data have been transferred or when all available data has been
transferred to the initiator, whichever is less. The 4-byte READ BUFFER header
is followed by data bytes from the target data buffer. The following figure
illustrates the format of the header.
Bit
Byte
7
6
5
4
3
2
1
0
0
Reserved
1 - 3
(MSB)
Available Length
(LSB)
Figure 5–60 READ BUFFER Header - Data Format
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: ......