The Log Parameter Descriptor - Sony DDS-4 Product Description Manual

6. COMMAND SPECIFICATION

6. 06. 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:
Bit 7
Byte
0 (MSB)
1
2 DU
3
4
n
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-field 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.
6 5
DS (1) TSD
Parameter Length (n-3)
Table 6-8: Log Parameter
4 3
Parameter Code
ETC TMC
Parameter Value
SONY SDT-10000/SDT-11000 DDS Tape Drive
2 1 0
(LSB)
Reserved LP
LOG SENSE
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