Advanced Host Controller Interface (AHCI) and Redundant Array of Independent Disks (RAID) on HP EliteDesk and EliteOne 705 Business PCs Using AMD Array Management Software (RAIDXpert2)

2
Introduction
A Redundant Array of Independent Disks (RAID) is a data storage scheme that uses two or more drives accessed in
combination to improve fault tolerance. Initially used with servers, desktop PCs are increasingly using RAID controllers
and extra ATA or SCSI disks. Newer system boards often have RAID controllers.
The HP EliteDesk and EliteOne 705 Business PCs take advantage of Serial Advanced Technology Attachment (SATA) and
the integration of RAID into AMD D4 chipsets. The HP EliteDesk and EliteOne 705 Business PC products incorporate RAID
drive support through factory configurations. This white paper provides a basic overview of RAID technology, supported
factory configurations of HP EliteDesk and EliteOne 705 Business PCs, and other supported RAID configurations.
Basics of AHCI and RAID Technology
Definitions
Table 1: Basic AHCI and RAID Definitions
Acronym or term Description
AHCI Advanced Host Controller Interface, a specification for hardware and software, is a register interface for
SATA intended to add higher speed, NCQ and other features.
ATA Advanced Technology Attachment, an interface standard to connect mass storage devices to the
system.
BIOS Basic Input/Output System, also known as system ROM.
Chipset Collection of integrated circuits that controls the functionality of the system. Chipsets are designed to
work with specific processors.
HDD Hard disk drive
GPT GUID Partition Table is a standard for the layout of the partition table on a physical hard disk, using
globally unique identifiers (GUID).
IDE An interface for mass storage devices in which the controller is integrated into the drive.
INF
Information file (.inf) used by Microsoft® operating systems that support the Plug & Play feature. When
installing a driver, this file provides the operating system needed, information about driver filenames,
driver components, and supported hardware.
Migration Term used to describe the movement of data from one configuration or usage model to another.
JBOD Just a Bunch of Disks. Logical drives concatenation (not tested or supported)
LD Logical Drive, a grouping of physical drives presented as a single drive.
MBR Master Boot Record, the boot sector that holds the hard drive configuration information such as the
boot code and logical partitions.
MDD Meta Data, i.e. previous RAID configuration information
Mirroring Fault tolerance method using 100% duplication of data on two drives (RAID 1). After a failed drive is
replaced, the RAID controller automatically rebuilds the lost data from the other two drives. RAID
systems may have a spare drive (hot spare) ready and waiting to be the replacement for a drive that
fails
NCQ Native Command Queuing, an extension of the SATA protocol that allows hard drives to reorder read and
write operations for optimal performance.
OS Operating System, software that controls the functions of the system hardware and applications.
Option ROM
Third party module that is loaded by the System BIOS which provides extended support for a particular
piece of hardware. The RAID Option ROM provides boot support for RAID volumes as well as a user
interface for managing and configuring the system's RAID volumes.
Parity
Mechanism for data integrity used for data recovery. Distributed parity is used in RAID 5 (requires 3 or
more drives) to spread parity information so if any one drive fails, the other drives can rebuild the data.
PCIe PCI Express, a bi-directional serial version of PCI.