Glossary of Hard Disk Drive Terminology (Letter B)

The amount of data that can be sent over a given circuit. See also buffer bandwidth.

BIOS (Basic input/output system)
A program or set of programs that control the basic functions of the computer.

An abbreviation for a binary digit which can be either 0 or 1. A bit is the basic data unit of all digital computers. It is usually part of a data byte, or data word; however, a single bit can be used to control or read logic ON/OFF functions. A bit is a single digit in a binary number. Bits are the basic unit of information capacity on a computer storage device. Eight bits equal one byte.

Bit density
Expressed as bits per inch (BPI), the number of bits that can be written onto one inch of track on a disk surface.

A group of bytes handled, stored, and accessed as a logical data unit, such as an individual file record. A block in UNIX workstation environments is the smallest contiguous area that can be allocated for the storage of data. (Note: A different definition of the term is used when referring to the physical configuration of a hard drive.)

To start or restart your computer; loading the operating system.

Bits per inch. Indicates the density of information on a hard drive. See bit density.

A temporary data storage area used to make up for a difference in data transfer rates and/or data processing rates between sender and receiver. For example, a printer buffer copies data from the computer and holds it until the printer is ready to print it.

Buffer Bandwidth
The speed of transferring data to or from the buffer.

In the computer industry, the assembly of a system in response to a customer’s order, rather than for inventory or mass shipment. A system utilized by Dell Computer and Gateway, now being emulated to some degree by other PC makers like IBM, HP and Compaq.

Business Model
A company’s financial plan, including product pricing and margin calculations.

Burst Mode Transfer Rate
The transfer rate into the buffer RAM of the hard disk. This rate does not factor in delays due to latencies or host delays. See also transfer rate.

The path that carries data between the computer (microprocessor) and peripheral devices. An IDE interface cable and a SCSI cable are both examples of a bus.

A sequence of eight binary digits or bits regarded to be a unit or binary word. The storage capacity of a disk drive is commonly measured in megabytes, which is the total number of storable bits divided by eight million.