Definition: byte

(BinarY TablE) The common unit of computer storage from desktop computer to mainframe. It is made up of eight binary digits (bits). A ninth bit may be used in the memory (RAM) circuits as a parity bit for error checking. See parity checking.

A byte holds one alphabetic character such as the letter A, a dollar sign or decimal point. For numeric data, one byte holds one decimal digit (0-9), two "packed decimal" digits (00-99) or a binary number from 0 to 255. See space/time.

Bit, Byte and Nibble
The term "bit" for "binary digit" was coined in the 1940s. In the 1950s, IBM coined the terms "byte" and "nibble" (half a byte) to maintain the mastication theme "bit, bite, nibble."

From Bite to Byte
IBM coined the term in the mid-1950s to mean the smallest addressable group of bits in a computer, which was originally not eight. The first spelling of the word was "bite," but the y was added to avoid misspelling between "bit" and "bite."

Byte Specifications
Drives and memory (RAM) are rated in bytes. For example, a 512-gigabyte (512GB) drive stores 512 billion characters of program instructions and data permanently, while eight gigabytes (8GBs) of RAM holds eight billion temporarily. The first hard drives in early personal computers held 5MB, and RAM was 64K. See memory and file size.

Eight Bits Make Up One Byte

There are eight binary digits (bits) in a byte, but there can also be nine bits per byte in RAM cells that include error correction (see parity checking).

The Bytes Got Really Small!

In 1991, this hard drive held 670 megabytes. By 2018, the microSD flash memory card (arrow) had 750 times as much storage. The disk weighs 17 pounds in its case (not shown), and the flash memory card weighs half a gram. See microSD.