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7K200 SATA OEM Specification
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12.15 Software 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
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
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,
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.
Set Features with a subcommand code of 06h. Software settings preservation is enabled by default.
12.15.1
Preserved software settings
If Software setting preservation is enabled, the following settings are preserved across COMRESET.
Otherwise settings are cleared across COMRESET.
Otherwise settings are cleared across COMRESET.