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Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification

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The LOG SELECT command provides a means for the Initiator to clear statistical information maintained by the drive and 
reported via the LOG SENSE command.

•  PCR The Parameter Code Reset determines whether the Log Sense parameters will be cleared and unit attention posted 

for all other Initiators. A value of 1 indicates that the parameters be cleared, while a value of zero (except when PC = 
11b) indicates that the parameters not be cleared. Parameter list length must be zero when PCR is 1.  The PC field is 
ignored for list parameters, i.e. when the Format and Linking (F&L) field contains 01b or 11b.

• SP The Save Parameters bit value of zero indicates that the page parameters not be saved. A value of 1 indicates that the 

page parameters that are savable be saved after they have been changed. SP bit MUST be 1 if parameter list length is 
greater than zero. Otherwise it will result in a Check Condition status being returned. The sense key shall be set to 
Illegal Request and additional sense code of Invalid Field in CDB. 

• PC The Page Control field defines the type of parameters to be selected. The PC field set to 11b (and PCR is then a don't 

care) indicates that the Default Cumulative values are set to their default values of 0. If the PC field is set to 01b and 
PCR is set to 1, the Current Cumulative values are also set to their default values of 0.

Parameter List Length MUST be zero when PC = 11b. Otherwise the command is terminated and a Check Condition 
status is returned. The sense key shall be set to Illegal Request and additional sense code of Invalid Field in CDB.

• Parameter List Length The Parameter List Length field specifies the length in bytes of the parameter list that shall be 

located in the DATA OUT buffer. A parameter list length zero indicates that no pages shall be transferred.

 A specified length greater than 0x00FF will result in a Check Condition status being returned. A length that results in 

log data being truncated will generate a Check Condition status.

Note: 

For page 0Fh, the maximum parameter list length supported is 4004h (4 bytes for the header and 100h bytes for each 

of the 40h parameters that are supported). The Parameter List Length must be an integral of the number of parameters plus the 
4 byte header. (Ex: Parameter length =104h for one parameter, 204h for 2 parameters,... 4004h for all 40h parameters).

The drive allows updates to the current cumulative values only. A value of zero is acceptable and is not considered an error.
The drive updates only pages 0Eh, the Start/Stop Cycle page and 0Fh, the Application Client page. For other pages the param-
eters are ignored. If the data out buffer contains multiple pages then the application client should send the pages in ascending 
order. If the data out buffer contains multiple log parameters within a page,all log parameters within the page should be sent