Fujitsu MBB2073RC, MBB2147RC manual Setting parameters

5.4Checking Operation after Installation and Preparing the HDDs for Use

5.4.3Setting parameters

The user can specify the optimal operation mode for the user system environments by setting the following parameters with the MODE SELECT or MODE SELECT EXTENDED command:

•Error recovery parameter

•Caching parameter

•Control mode parameter

With the MODE SELECT or MODE SELECT EXTENDED command, specify 1 for the "SP" bit on CDB to save the specified parameter value on the disk. This enables the HDDs to operate by using the parameter value set by the user when power is turned on again.

When the parameters are not set or saved with the MODE SELECT or MODE SELECT EXTENDED command, the HDDs set the default values for parameters and operates when power is turned on or after reset. Although the HDD operations are assured with the default values, the operations are not always optimal for the system. To obtain the best performance, set the parameters in consideration of the system requirements specific to the user.

This section outlines the parameter setting procedures. Refer to Subsection 4.1.4 “MODE

SELECT (15)”, 4.1.5 “MODE SELECT EXTENDED (55)” of the SAS INTERFACE MANUAL for further details of the MODE SELECT and MODE SELECT EXTENDED commands and specifying the parameters.

1.At factory shipment of the HDDs, the saving operation for the MODE SELECT parameter is not executed. So, if the user does not set parameters, the HDDs operate according to the default value of each parameter.

2.The MODE SELECT parameter is not saved for each Loop ID of but as the common parameter for all initiator. In the multi-initiator system, parameter setting cannot be changed for each initiator.

3.Once parameters are saved, the saved value is effective as long as next saving operation is executed from the initiator. For example, even if the initialization of the disk is performed by the FORMAT UNIT command, the saved value of parameters described in this section is not affected.

4.When the HDDs, to which the saving operation has been executed on a system, are connected to another system, the user must pay attention to that the HDDs operate according to the saved parameter value if the saving operation is not executed at installation.

5.The saved value of the MODE SELECT parameter is assumed as the initial value of each parameter after the power-on, the RESET condition. The initiator can change the parameter value temporary (actively) at any timing by issuing the MODE SELECT or MODE SELECT EXTENDED command with specifying "0" to the SP bit in the CDB.

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