RAID - User Guide

4 Intel Rapid Storage Technology
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 Computer Setup (BIOS) for these features to apply (see Enable RAID using
the Computer Setup (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 a hard drive 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 hard drive receives read requests. Native Command Queuing (NCQ)
allows SATA hard drives 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 Computer Setup (BIOS), SATA controller, and controller
driver.
Hot plug capability
Hot plug capability allows the SATA recovery hard drive to be removed or inserted while the computer
is running. Hot plug capability is supported when the recovery hard drive is connected to the eSATA
port or located in the docking station's SATA-swappable bay. For example, the recovery hard drive in
the docking station's SATA-swappable bay can be removed while the computer is running if you need
to temporarily insert an optical drive in the bay. Hot plug capability also allows you to dock and
undock the computer at any time.
Intel Smart Response Technology (select models only)
NOTE: Intel® Smart Response Technology requires that the SATA controller be set to RAID mode
in Computer Setup (BIOS). Typically, SRT is already enabled and in RAID mode from the factory, and
no further user configuration is required.
Intel Smart Response Technology (SRT) is an Intel Rapid Storage Technology (RST) caching feature
that significantly improves computer system performance. It allows a user to configure computer
systems with an SSD mSATA module used as cache memory between the hard disk drive and
system memory. This configuration provides the advantage of having a hard disk drive (or a RAID
volume) for maximum storage capacity while simultaneously delivering an enhanced system
performance experience.
NOTE: Intel Smart Response Technology caching is implemented as a single drive-letter solution.
No additional drive letter is required for the SSD device used as a cache. Typically, SRT is enabled
from the factory, and no further user configuration is required. SRT is not supported when used with
SSD or SED drives.
Advanced Host Controller Interface 9