Specifications

ATAPI For Streaming Tape QIC-157 Rev B
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6.8.5. LOG SELECT Command
The LOG SELECT command provides a means to manage statistical information maintained by the
Device about the Device. Devices that implement the LOG SELECT command shall also implement
the LOG SENSE command. Structures as log parameters within log pages are defined as a way to
manage the log data. The LOG SELECT command provides for sending zero or more log pages of
data. This specification defines the format of the log pages, but does not define the exact conditions
and events that are logged.
Table 6-16 Log Select Command
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation code (4Ch)
1 Reserved PCR 0 (SP)
2 PC Reserved
3 Reserved
4 Reserved
5 Reserved
6 Reserved
7 (MSB) Parameter List Length
8 (LSB)
9 Reserved
10 Reserved
11 Reserved
A Parameter Code Reset (PCR) bit of one and a parameter list length of zero shall cause all
implemented parameters to be set to zero. If the PCR bit is one and a the parameter list length is
greater than zero, the command is terminated 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
COMMAND PACKET. A PCR bit of zero specifies that the log parameters shall not be reset.
The Page Control (PC) field defines the type of parameter values to be selected. The page control
field is defined in Table 6-17 Page Control Field.
Table 6-17 Page Control Field
PC Value LOG SENSE LOG SELECT
00b Reserved Reserved
01b Current Cumulative Values Cumulative Values
10b Reserved Reserved
11b Reserved Reserved
[Implementor's Note: LOG SENSE commands should be issued prior to issuing LOG SELECT commands to determine
supported pages and page lengths.]