A central processing unit (CPU) contained within a single chip (integrated circuit). The term originated in the 1970s when processors were first miniaturized. Today, all CPUs are microprocessors, and server, desktop, laptop, smartphone and tablet microprocessors have more than one processing unit (see dual core
The term is often abbreviated MPU for "microprocessor unit" or just MP, the latter also spelled with the Greek µ symbol for micro or the letter "u" as an alternate (µP or uP).
From 8-Bit to 64-Bit
The earliest microprocessors were created by Texas Instruments, Intel and Scotland-based Pico Electronics, but who was really first has been debated. First-generation 8-bit microprocessor families were Intel's 8080, Zilog's Z80, Motorola's 6800 and Rockwell's 6502.
Today, the 32-bit and 64-bit microprocessors found in workstations and servers are x86, POWER and SPARC, while ARM leads the mobile market. The chips used in toys, appliances, vehicles and myriad other products are 8-, 16- and 32-bit microcontrollers, which include the microprocessor (see microcontroller
). All together billions of microprocessors are made and shipped each year. See chip
, embedded system
, process technology
, 16-bit computing
, 32-bit computing
and 64-bit computing
The 386 Microprocessor
From 2K to Four Billion
No technology is more incredible than the microprocessor. This older 386 chip contains a mere 275,000 transistors, and some slight detail can be seen. Contemporary chips at this magnification level show up only as a sea of gray. See chip
. (Image courtesy of Intel Corporation.)
This is a sampling of the number of transistors on a chip. It is not a comparison as many brands have similar transistor counts.