Hitachi HDS723020BLA642 Software Setting Preservation Feature Set, Preserved software settings

Models: HDS723020BLA642

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7K200 SATA OEM Specification

12.15Software Setting Preservation Feature Set

When a device is enumerated, software will configure the device using Set Features and other commands. These software settings are often preserved across software reset but not necessarily across hardware reset. In Parallel ATA, only commanded hardware resets can occur, thus legacy software only reprograms settings that are cleared for the particular type of reset it has issued. In Serial ATA, COMRESET is equivalent to hard reset and a non-commanded COMRESET may occur if there is an asynchronous loss of signal. Since COMRESET is equivalent to hardware reset, in the case of an asynchronous loss of signal some software settings may be lost without legacy software knowledge. In order to avoid losing important software settings without legacy driver knowledge, the software settings preservation ensures that the value of important software settings is maintained across a COMRESET. Software settings preservation may be enabled or disabled using Set Features with a subcommand code of 06h. Software settings preservation is enabled by default.

12.15.1Preserved software settings

If Software setting preservation is enabled, the following settings are preserved across COMRESET. Otherwise settings are cleared across COMRESET.

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Hitachi HDS723020BLA642 manual Software Setting Preservation Feature Set, Preserved software settings