SCSI Primary Commands - 2.pdf

T10/1236-D Revision 20 18 July 20017.8.2 Current valuesA PC field value of 00b requests that the device server return the current values of the mode parameters. Thecurrent values returned are:a) the current values of the mode parameters established by the last successful MODE SELECT command;b) the saved values of the mode parameters if a MODE SELECT command has not successfully completedsince the last power-on or hard reset condition; orc) the default values of the mode parameters, if saved values, are not available or not supported.7.8.3 Changeable valuesA PC field value of 01b requests that the device server return a mask denoting those mode parameters that arechangeable. In the mask, the fields of the mode parameters that are changeable shall be set to all one bits and thefields of the mode parameters that are non-changeable (i.e., defined by the target) shall be set to all zero bits.Implementation of changeable page parameters is optional. If the target does not implement changeable parameterspages and the device server receives a MODE SENSE command with 01b in the PC field, the command shallbe terminated with CHECK CONDITION status. The sense key shall be set to ILLEGAL REQUEST, and theadditional sense code set to INVALID FIELD IN CDB.An attempt to change a non-changeable mode parameter using the MODE SELECT command shall result in anerror condition (see 7.6).The application client should issue a MODE SENSE command with the PC field set to 01b and the PAGE CODE fieldset to 3Fh to determine which mode pages are supported, which mode parameters within the mode pages arechangeable, and the supported length of each mode page prior to issuing any MODE SELECT commands.7.8.4 Default valuesA PC field value of 10b requests that the device server return the default values of the mode parameters. Unsupportedparameters shall be set to zero. Default values should be accessible even if the device is not ready.7.8.5 Saved valuesA PC field value of 11b requests that the device server return the saved values of the mode parameters. Implementationof saved page parameters is optional. Mode parameters not supported by the target shall be set to zero. Ifsaved values are not implemented, the command shall be terminated with CHECK CONDITION status, the sensekey set to ILLEGAL REQUEST and the additional sense code set to SAVING PARAMETERS NOT SUPPORTED.The method of saving parameters is vendor specific. The parameters are preserved in such a manner that they areretained when the device is powered down. All savable pages should be considered saved when a MODESELECT command issued with the SP bit set to one has returned a GOOD status or after the successfulcompletion of a FORMAT UNIT command.7.8.6 Initial responsesAfter a power-up condition or hard reset condition, the device server shall respond in the following manner:a) If default values are requested, report the default values;b) If saved values are requested, report valid restored mode parameters, or restore the mode parameters andreport them. If the saved values of the mode parameters are not able to be accessed from the nonvolatilevendor specific location, terminate the command with CHECK CONDITION status and set the sense keyset to NOT READY. If saved parameters are not implemented respond as defined in 7.8.5; or102 dpANS SCSI Primary Commands - 2 (SPC-2)