User Manual

SCSI Commands Reference Manual, Rev. J 102
www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)
PC (Page Control) field
The page control (PC) field specifies which data counter parameter values (i.e., when the FORMAT AND LINKING field (see 5.2.2) contains 00b or
10b) shall be processed by a device server in response to a LOG SELECT command as described in table 66. The PC field shall be ignored for list
parameters (i.e., when the FORMAT AND LINKING field contains 01b or 11b).
The threshold values and cumulative values for data counter parameters are:
1) the current values if there has been an update to a cumulative parameter value (e.g., by a LOG SELECT command or by a device specific
event) in the specified page or pages since the last logical unit reset occurred;
2) the saved values, if saved parameters are implemented, current values have been saved, and an update has not occurred since the last
logical unit reset; or
3) the vendor specific default values, if saved values are not available or not implemented.
When evaluated together, the combination of the values in the PCR bit, the SP bit, and the PC field specify the actions that a SCSI
target device performs while processing a LOG SELECT command (see table 68).
PARAMETER LIST LENGTH field
If the PARAMETER LIST LENGTH field is set to zero, the PAGE CODE field and SUBPAGE CODE field specify the log page or log pages to which the
other CDB fields apply (see 3.7.1).
Since each log page in the parameter list contains a PAGE CODE field and SUBPAGE CODE field (see 5.2.2), the command shall be terminated
with CHECK CONDITION status, with the sense key set to ILLEGAL REQUEST, and the additional sense code set to INVALID FIELD IN CDB, if:
a) the PARAMETER LIST LENGTH field contains a value other than zero, and:
A) the PAGE CODE field contains a value other than zero; or
B) the SUBPAGE CODE field contains a value other than zero.
The PARAMETER LIST LENGTH field specifies the length in bytes of the parameter list that shall be located in the Data-Out Buffer.
If the PARAMETER LIST LENGTH field contains zero, no log pages shall be transferred. This condition shall not be considered an error. The LOG
SELECT command shall be processed as described in
3.7.1.
Table 66 Page Control (PC) field values
Values Description
00b
Threshold values
01b
Cumulative values
10b
Default threshold values
11b
Default cumulative values