8-bit: Information and Much More from Answers.com

This article is about 8-bit in computer architecture. For music in the 8-bit style, see 8-bit (music).

Microprocessors
4-bit	8-bit	16-bit	24-bit	31-bit	32-bit	48-bit	64-bit	128-bit
Applications
8-bit		16-bit		31-bit	32-bit		64-bit
Data Sizes
4-bit	8-bit	16-bit			32-bit		64-bit	128-bit
nibble byte octet word dword qword

In computer architecture, 8-bit integers, memory addresses, or other data units are those that are at most 8 bits (1 octet) wide. Also, 8-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. Eight-bit CPUs normally use an 8-bit data bus and a 16-bit address bus which means that their address space is limited to 64 KiBs. This is not a "natural law", however, so there are exceptions.

The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 (compatible with the 8080) and the Motorola 6800 were also used in similar computers. The Z80 and the MOS Technology 6502 8-bit CPUs were widely used in home computers and game consoles of the 70s and 80s. Many 8-bit CPUs or microcontrollers are the basis of today's ubiquitous embedded systems.

There are 2⁸ (256) possible permutations for 8 bits.(in binary)

About 55% of all CPUs sold in the world are 8-bit microcontrollers or microprocessors. ^{[citation needed]}

Why 8 bits?

4-bit microprocessors were developed in the early 1970s starting with the Intel 4004. Intel swiftly followed with 8-bit processors, and most competitors to Intel started with 8-bits. This, combined with the performance and memory limitations of the available 4-bit processors, meant that they fell out of commercial application quickly.

List of 8-bit CPUs

A CPU can be classified on the basis of the data it can access in a single operation. An 8-bit processor can access 8 bits of data in a single operation, as opposed to a 16-bit processor, which can access 16 bits of data in a single operation.

8-bit Intel CPUs

• Intel 8008
• Intel 8051
• Intel 8080
• Intel 8085
• Intel 8088 ^*NOTE: Intel 8088 is 8-bit externally only
• Intel 80188 ^*NOTE: Intel 8088 is 8-bit externally only

List of competitor compatible CPUs to Intel 8-bit architecture

• Zilog Z80
• Zilog Z800

8-bit Motorola CPUs

see main article: 68h

• Motorola 6800

List of competitor CPUs similar to Motorola 8-bit architecture

• MOS Technology 6501
• MOS Technology 6502
• MOS Technology 6510