4Intel Rapid Storage Technology features
Intel Rapid Storage Technology supports the following Recovery features.
Advanced Host Controller Interface
The Advanced Host Controller Interface (AHCI) is a specification that allows the storage driver to enable advanced SATA features such as Native Command Queuing and hot plug capability. AHCI must be enabled in the system BIOS for these features to apply (see Enable RAID through the system BIOS (f10) on page 13). AHCI is enabled by default on supported HP Business computers.
Native Command Queuing
A read/write drive head writes data to an HDD platter in concentric circles (tracks) based on the order in which the write request was received. Because applications rarely request data in the same order that it was written to the platter, long delays (latency) would result if the drive head had to locate data in the exact order that the HDD receives read requests. Native Command Queuing (NCQ) allows SATA HDDs to accept multiple commands and change their execution order to improve performance. This is analogous to the way an elevator reorders floor requests to minimize travel time and mechanical wear. Similarly, NCQ reduces the latency and unnecessary drive head movement required to execute multiple outstanding read/write requests, resulting in increased performance and reliability. NCQ requires support from the system BIOS, SATA controller, and controller driver.
Hot plug capability
Hot plug capability allows the SATA recovery HDD to be removed or inserted while the computer is running. Hot plug capability is supported when the recovery HDD is connected to the eSATA port or located in the docking station's
10 Chapter 4 Intel Rapid Storage Technology features