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F A U L T TO L E R A N C E — Fault tolerance is the capability of the disk subsystem to undergo a single drive failure for the physical disks in a virtual disk without compromising data integrity and processing capability. The PERC S100 controller and PERC S300 controller provide this support through redundant virtual disks in RAID levels 1, 5 and 10. Fault tolerance is often associated with system availability because it allows the system to be available during drive failures. In case a disk fails, the PERC S100 controller and

PERC S300 controller support hot spare disks and the auto-rebuild feature.

F I R M W A R E — Software stored in read-only memory (ROM) or Programmable ROM (PROM). Firmware is often responsible for the behavior of a system when it is first turned on. A typical example would be a monitor program in a system that loads the full operating system from disk or from a network and then passes control to the operating system.

F O R M A T — The process of writing a specific value to all data fields on a physical disk, to map out unreadable or bad sectors. Because most physical disks are formatted when manufactured, formatting is usually done only if a physical disk generates many media errors.

GB — Acronym for gigabyte(s). A gigabyte equals 1,024 megabytes or 1,073,741,824 bytes (2^30 bytes).

GPT (GUID P A R T I T I O N TA B L E ) — A standard for the layout of the partition table on a physical hard disk.

G L O B A L L Y U N I Q U E ID E N T I F I E R (GUID) — A unique reference-number identifier used in software applications.

HBA (H O S T B U S A D A P T O R ) — An adaptor card that includes the I/O logic, software and processing to manage the transfer of information between the host system and devices connected to it.

H O S T S YS T E M — Any system on which the RAID controller is installed. Mainframes, workstations, and personal systems can all be considered host systems.

H O T S P A R E — An idle, powered on, stand-by physical disk ready for immediate use in case of disk failure. It does not contain any user data. A hot spare can be dedicated to a single redundant virtual disk or it can be part of the global hot-spare pool for all virtual disks controlled by the controller. When a disk fails, the PERC S100 controller or PERC S300 controller automatically replaces and rebuilds the data from the failed physical disk to the hot spare. Data can be rebuilt only from virtual disks with redundancy (RAID levels 1, 5, or 10; not RAID 0), and the hot spare must have sufficient capacity. If the hot spare is designated as having enclosure affinity, it attempts to rebuild any failed disks on the backplane within which it resides before rebuilding any other on other backplanes.

Glossary

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