Hitachi HTS541640J9SA00 manual Software Setting Preservation Feature Set, Native Command Queuing

Travelstar 5K160 (SATA) Hard Disk Drive 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.

Setting

Contents

Initialize device parameters	Track length
	Number of head
	Number of cylinder
	Capacity
Power Management Feature Set Standby Timer	Time to fall into standby mode
Security mode state	Security freeze lock
	Security unlock
Set max address	Capacity
Set feature	Write Cache Enable/Disable
	Set Transfer Mode
	Advanced Power Management Enable/Disable
	Read Look-Ahead
	Reverting to Defaults
Set multiple mode	Block size

Figure 19 Preserved Software Setting

12.16Native Command Queuing

Native Command Queuing feature (Read / Write FPDMA Queued commands) is supported. Please refer to the Serial ATA II Specification about Native Command Queuing.

The host shall not issue a legacy ATA command while a native queued command is outstanding. Upon receiving a legacy ATA command while a native queued command is outstanding, the device aborts the command and halts command processing of outstanding native queued commands.

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