7. ATAPI Packet Command Specification
LOG SENSE
SONY AIT-1 Turbo drive SDX-470V series Ver.1.0
7-14
Table 7-12: LOG PAGE Page Descriptor
Bit
Byte
7 6 5 4 3 2 1 0
0
Reserved Page
Code
1
Reserved
2
(MSB)
3
Page Length (n-3)
(LSB)
Log Parameter(s)
4
Log Parameter (First)
x+3
(Length x)
n-y
Log Parameter (Last)
n
(Length y)
Page code:
Identifies which page of data is being transferred. If the Page Code field value is reserved or not
implemented by the target, the target shall terminate the command with a CHECK CONDITION status. The sense
key shall be set to ILLEGAL REQUEST, and the additional sense code shall be set to INVALID FIELD IN
PARAMETER LIST.
Page Length:
The Page Length field indicates the total number of bytes that follow this byte. The value returned
for this field depends on the value you specified for the Page Code and the Parameter Pointer in the CDB. This
value is independent of what you specified for the Allocation Length. A Page Length value that results in the
truncation of any parameter shall cause the target to terminate the command with CHECK CONDITION status.
The sense key shall be set to ILLEGAL REQUEST and the additional sense code shall be set to INVALID FIELD
IN PARAMETER LIST.
7.6.2.
The Log Parameter Descriptor
Most log pages contain one or more special data structures called log parameters. These may be data counters
which record the occurrence of certain events, or they may be more complex structures which describe activities
or other events which occur within the device. Each parameter structure begins with a 4-byte parameter header
followed by one or more bytes of parameter structure data. The 4-byte header is shown below:
Table 7-13: LOG PAGE Parameter Descriptor
Bit
Byte
7 6 5 4 3 2 1 0
0
(MSB)
1
Parameter Code
(LSB)
2
DU (0)
DS (1)
TSD (0)
ETC (0)
TMC (00)
Reserved
LP (0)
3
Parameter Length (n-3)
4
n
Parameter Value
Parameter Code:
Identifies which parameter of data is being transferred. If the parameter code value is reserved
or not implemented by the target, then the target shall terminate the command with CHECK CONDITION status.
The sense key shall be set to ILLEGAL REQUEST and the additional sense code shall be set to INVALID FIELD
IN PARAMETER LIST.
The DU, DS, TSD, ET, TMC, and LP fields are collectively referred to as the control byte.
DU:
The DU bit (Disable Update) is not defined for threshold values (indicated by the PC field of the LOG SENSE
command descriptor block). The target shall ignore the value of any DU bits in a LOG SELECT command.
DS:
The DS bit informs the initiator that savable parameters are disabled (i.e. not supported), and should always
be 1. If it is 0 the command will terminate with CHECK CONDITION status with sense key set to ILLEGAL
REQUEST and additional sense code of ILLEGAL FIELD IN PARAMETER LIST.
