A *bit* is the smallest unit of information that can be stored or manipulated on a computer; it consists of either zero or one. Depending on meaning, implication, or even style it could instead be described as false/true, off/on, no/yes, and so on. We can also call a *bit* a *binary* digit, especially when working with the 0 or 1 values.

A *bit* is not just the smallest unit of information, but for sake of discussion it can be said that a *bit* is also the largest unit of information a computer can manipulate. The *bits* are bunched together so the computer uses several *bits* at the same time, such as for calculating numbers. When a "bunch" means eight *bits* then it is called a *byte*.

A *byte* also happens to be how many *bits* are needed to represent letters of the alphabet and other characters. For example, the letter "**A**" would be **01000001**; my initials "**KJW**" would be **010011000100110101010110**. To make this a little bit easier to see where the bytes are it is customary place a comma every four digits, to make what are sometimes called *nibbles*: **0100,1100,0100,1101,0101,0110**. That's not really much easier for people to read or write--and many computer engineers, programmers, and analysts need to read and write even longer *binary* codes than this.

It so happens that there are only 16 different ways to write 0's and 1's four times. So something called *hexademical* code can be used to make the numbers shorter by translating each *nibble* (or half-a-byte) like this:

Binary: | 0000 | 0001 | 0010 | 0011 | 0100 | 0101 | 0110 | 0111 | 1000 | 1001 | 1010 | 1011 | 1100 | 1101 | 1110 | 1111 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|

Hexademical: | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F |

So my initials would look like this:

Letter: (or bytes) | K | J | W | |||
---|---|---|---|---|---|---|

Binary: (or nibbles) | 0100 | 1100 | 0100 | 1101 | 0101 | 0110 |

Hexadecimal: (also nibbles) | 4 | B | 4 | C | 5 | 7 |

So of course "**4B4C57**" is much easier to understand than "**010011000100110101010110**". To make it even a little bit easier to use commas are usually put in every 4^{th} *hexademical* character just like was done for the *binary* digits. That would make my initials look like "**4B,4C57**". A group of 4 *hexademical* characters -- which would be 16 *bits* long -- is called a *halfword*.

Copyright © 1999 Kevin J. Walsh | |

walsh@njit.edu /KJW | |