Glossary of Western Digital Hard Disk Drive (Letter I)

Input/Output. An operation, program, or device that that transfers data to or from a computer or other device.

3.5-inch mounting frame with a built-in heat sink that keeps the 2.5-inch WD VelociRaptor extra cool when installed in a 3.5-inch drive bay.

Integrated drive electronics. A technology in which interface controller electronics are incorporated into the design of the hard drive rather than into a separate controller. See also PATA.

index pulse signal
A digital pulse signal indicating the beginning of a disk revolution. An embedded servo pattern or other prerecorded information is present on the disk following the index.

See low-level formatting.

A device in control of a SCSI bus that sends commands to a target. Most SCSI devices have a fixed role as either initiator or target; however, some devices can assume both roles.

Incoming data that a computer processes, such as user-issued commands.

Delivers lower power consumption by automatically unloading the heads during idle to reduce aerodynamic drag.

A fine-tuned balance of spin speed, transfer rate, and caching algorithms designed to deliver both significant power savings and solid performance.

WD AV feature that optimizes seek speeds to lower power consumption, noise, and vibration.

A hardware or software protocol to manage the exchange of data between a device and a computer; the most common ones are PATA (also known as EIDE), SATA, and SCSI.

interface controller
A chip or circuit that translates computer data and commands into a form usable by a hard drive and that controls data transfers between buffer and host. See also disk controller and disk drive controller.

The arrangement of sectors on a track.

A signal sent by a subsystem to the CPU when a process either was completed or could not be completed.

Internet Protocol. A system that controls how data messages are separated into packets, routed from the sender, and reassembled at the destination.

IP address
A 32-bit, binary number that uniquely identifies a computer connected to the Internet.

Industry Standard Architecture. The standard 16-bit AT bus for the PC/AT system. ISA was the only industry standard bus for PCs until the recent release of Peripheral Component Interconnect (PCI).