Glossary

array

(n.) Multiple disk drives that function as a single storage element and is managed by the NAS appliance. The array consists of one controller unit and, optionally, up to two expansion units.

AWG

(American wire gauge) (n.) A unit for measuring the thickness of wire.

back-end storage

The trays of disk drives. A tray with a RAID controller is called a controller unit; a tray without a controller is called an expansion unit. See also controller unit and expansion unit.

configuration

(1) (n.) The manner in which the software and hardware of an information processing system are organized and interconnected. (2) (n.) The physical and logical arrangement of programs and devices that make up a data processing system. (3) (n.) The devices and programs that make up a system, subsystem, or network.

controller unit

A RAID controller and up to 16 disk drives. See also expansion unit.

CIFS

Common Internet File System

driver

(n.) A software program that enables a computer to communicate with a peripheral device.

DNS

Domain Name Service

expansion unit

A tray with up to 16 disk drives but no RAID controller. This type of unit expands the capacity of an array and must be attached to a controller unit to function. See also controller unit.

Fast Ethernet

(n.) A high-speed version of Ethernet transmitting data at 100 Mbps. Fast Ethernet networks use the same media access control method that 10BASE-T Ethernet networks use but achieve 10 times the data transmission speed.

See Fibre Channel

Fibre Channel (FC)

A set of standards for a serial I/O bus capable of transferring data between two ports at up to 100 MBytes/second. Fibre Channel supports point to point, arbitrated loop, and switched topologies.

(gigabyte) (n.) A unit of information equal to 1024 megabytes.

Gigabit Ethernet

(n.) An Ethernet technology that enables data transfer rates of up to 1 Gbps using optical fiber cable or unshielded twisted-pair cable.

hot-swap

(v.) To replace a failed component without interruption of system service.

HBA

See host bus adapter.

host bus adapter(HBA)

An I/O adapter than connects a host I/O bus to a computer's memory system. (SNIA)

(kilobyte) (n.) A unit of information equal to 1024 bytes.

LAN

(local area network) (n.) A data communications network that is limited geographically limited (about 1 km radius).

LCD

(liquid crystal display) (n.) A low-power display technology that uses rod-shaped crystal molecules that change their orientation when an electrical current flows through them.

LED

(light-emitting diode) (n.) A semiconductor device that converts electrical energy into light.

LUN

logical unit number

(megabyte) (n.) A unit of information equivalent to 1,048,576 bytes or 1024 kilobytes. Most uses of "megabyte," however, refer to exactly 1 million bytes.

MHz

(megahertz) (n.) A measure of frequency equivalent to 1 million cycles per second.

MTBF

(Mean Time Between Failures) (n.) The estimated time a device operates before a failure occurs.

NAS

(network-attached storage) (n.) A storage appliance that connects directly to the network. NAS does not usually perform network directory services or function as an application server; instead, it augments storage capacities. Quick and easy to set up, NAS appliances also typically provide cross-platform file sharing.

NFS

Network File System

NIC

(network interface card) (n.) An adapter that lets you connect a network cable to a microcomputer. The card includes encoding and decoding circuitry and a receptacle for a network cable connection.

NIS

Network Information Service

patch

A software or firmware update for a storage device or device component.

RAID

(Redundant Array of Independent Disks) (n.) A group of hard disks under the control of management software that work together to improve performance and decrease the odds of losing data to mechanical or electronic failure by using techniques such as data striping.

RAID-5

(n.) The most common RAID implementation. RAID-5 uses striping methods to store data.

SAN

(storage area network) (n.) A network that includes various storage devices shared by multiple servers.

SCSI

(Small Computer Systems Interface) (n.) A standard interface for personal computers that enables you to connect up to 15 peripheral devices, such as CD-ROM drives.

SCSI bus

(n.) A pathway between SCSI hardware devices.

SCSI host adapter

(n.) A printed circuit board (also called an interface card) that enables the computer to use a peripheral device for which it does not already have the necessary connections or circuit boards.

SCSI ID

(n.) Priority number (address) of a SCSCI device in a SCSI device chain. Only one device at a time can transmit through a SCSI connection (port), and priority is given to the device with the highest priority address. SCSI IDs range from 0 to 15, and each SCSI device must be given a unique and unused SCSI ID.

SFP

(Small form-factor pluggable) (n). A specification for optical transceivers. Devices are designed for use with small form factor (SFF) connectors, and offer high speed and physical compactness.

SMB

(server message block) (n.) A Microsoft-compatible network protocol for exchanging files. SMB is typically used by Microsoft Windows for Workgroups, OS/2 Warp Connect, and DEC Pathworks.

striping

(n.) A method for data storage in which a defined amount of data is written to the first drive in an array. The next amount of data is written to the second drive in the set, and so on. The primary advantage of striping the data is the ability for all drives to process read and write operations simultaneously.