User Manual

SCSI Commands Reference Manual, Rev. J 141
www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)
3.18 READ (16) command
The READ (16) command (see table 100) requests that the device server read the specified logical block(s) and transfer them to
the data-in buffer. Each logical block read includes user data and, if the medium is formatted with protection information
enabled, protection information. Each logical block transferred includes user data and may include protection information,
based on the RDPROTECT field and the medium format.
DLD2, DLD1 and DLD0 bits
The command duration time (see SAM-5) is specified by the command duration limit descriptor (see 5.3.10 and 5.3.11) specified by the DLD2
bit, the DLD1 bit, and the DLD0 bit, as shown in table 101. The CDLP field in the REPORT SUPPORTED OPERATION CODES parameter data (see
SPC-5) indicates that the command duration limit descriptor is in the Command Duration Limit A mode page or the Command Duration Limit
B mode page (see 5.3.10 and 5.3.11).
The CONTROL byte is defined in Clause 2.2.7
See the READ (10) command for the definitions of the other fields in this command.
Table 100 READ (16) command
Bit
Byte
7 6 5 4 3 2 1 0
0
OPERATION CODE (88h)
1
RDPROTECT DPO FUA RARC Obsolete DLD2
2
(MSB)
LOGICAL BLOCK ADDRESS
. . .
9
(LSB)
10
(MSB)
TRANSFER LENGTH
. . .
13
(LSB)
14
DLD1 DLD0 GROUP NUMBER
15
CONTROL
Table 101 Force unit access for read operations
Duration limit descriptor value bits
Command duration limit descriptor specifying command duration time
DLD2 DLD1 DLD0
0b 0b 0b
Command is not a duration limited command (see SAM-5)
0b 0b 1b
First command duration limit descriptor
0b 1b 0b
Second command duration limit descriptor
0b 1b 1b
Third command duration limit descriptor
1b 0b 0b
Fourth command duration limit descriptor
1b 0b 1b
Fifth command duration limit descriptor
1b 1b 0b
Sixth command duration limit descriptor
1b 1b 1b
Seventh command duration limit descriptor