Microprocessor
Overview
 
A microprocessor incorporates the functions of a computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

's central processing unit
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 (CPU) on a single integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

, (IC) or at most a few integrated circuits. It is a multipurpose, programmable
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

 device that accepts digital data
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...

 as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic
Sequential logic
In digital circuit theory, sequential logic is a type of logic circuit whose output depends not only on the present input but also on the history of the input. This is in contrast to combinational logic, whose output is a function of, and only of, the present input...

, as it has internal memory. Microprocessors operate on numbers and symbols represented in the binary numeral system
Binary numeral system
The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...

.
Encyclopedia
A microprocessor incorporates the functions of a computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

's central processing unit
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 (CPU) on a single integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

, (IC) or at most a few integrated circuits. It is a multipurpose, programmable
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

 device that accepts digital data
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...

 as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic
Sequential logic
In digital circuit theory, sequential logic is a type of logic circuit whose output depends not only on the present input but also on the history of the input. This is in contrast to combinational logic, whose output is a function of, and only of, the present input...

, as it has internal memory. Microprocessors operate on numbers and symbols represented in the binary numeral system
Binary numeral system
The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...

. The advent of low-cost computers on integrated circuits has transformed modern society. General-purpose microprocessors in personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

s are used for computation, text editing, multimedia display, and communication over the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

. Many more microprocessors are part of embedded system
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...

s, providing digital control of a myriad of objects from appliances to automobiles to cellular phones and industrial process control.

Origins

During the 1960s, computer processors were constructed out of small and medium-scale ICs each containing from tens to a few hundred transistors. For each computer built, all of these had to be placed and soldered onto printed circuit boards, and often multiple boards would have to be interconnected in a chassis. The large number of discrete logic gate
Logic gate
A logic gate is an idealized or physical device implementing a Boolean function, that is, it performs a logical operation on one or more logic inputs and produces a single logic output. Depending on the context, the term may refer to an ideal logic gate, one that has for instance zero rise time and...

s used more electrical power—and therefore, produced more heat—than a more integrated design with fewer ICs. The distance that signals had to travel between ICs on the boards limited the speed at which a computer could operate.

In the NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 Apollo space missions to the moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 in the 1960's and 1970's, all onboard computations for primary guidance, navigation and control were provided by a small custom processor called "The Apollo Guidance Computer
Apollo Guidance Computer
The Apollo Guidance Computer provided onboard computation and control for guidance, navigation, and control of the Command Module and Lunar Module spacecraft of the Apollo program...

". It utilized a primitive gate array
Gate array
A gate array or uncommitted logic array is an approach to the design and manufacture of application-specific integrated circuits...

 whose only logic elements were three-input NOR gate
NOR gate
The NOR gate is a digital logic gate that implements logical NOR - it behaves according to the truth table to the right. A HIGH output results if both the inputs to the gate are LOW . If one or both input is HIGH , a LOW output results. NOR is the result of the negation of the OR operator...

s.

The integration of a whole CPU onto a single chip or on a few chips greatly reduced the cost of processing power. The integrated circuit processor was produced in large numbers by highly automated processes, so unit cost was low. Single-chip processors increase reliability as there were many fewer electrical connections to fail. As microprocessor designs get faster, the cost of manufacturing a chip (with smaller components built on a semiconductor chip the same size) generally stays the same.

Microprocessors integrated into one or a few large-scale ICs the architectures that had previously been implemented using many medium- and small-scale integrated circuits. Continued increases in microprocessor capacity have rendered other forms of computers almost completely obsolete (see history of computing hardware
History of computing hardware
The history of computing hardware is the record of the ongoing effort to make computer hardware faster, cheaper, and capable of storing more data....

), with one or more microprocessors used in everything from the smallest embedded system
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...

s and handheld device
Handheld device
A mobile device is a small, hand-held computing device, typically having a display screen with touch input and/or a miniature keyboard and less than . Early pocket sized ones were joined in the late 2000s by larger but otherwise similar tablet computers...

s to the largest mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

s and supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...

s.

The first microprocessors emerged in the early 1970s and were used for electronic calculator
Calculator
An electronic calculator is a small, portable, usually inexpensive electronic device used to perform the basic operations of arithmetic. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.The first solid-state electronic...

s, using binary-coded decimal
Binary-coded decimal
In computing and electronic systems, binary-coded decimal is a digital encoding method for numbers using decimal notation, with each decimal digit represented by its own binary sequence. In BCD, a numeral is usually represented by four bits which, in general, represent the decimal range 0 through 9...

 (BCD) arithmetic on 4-bit words. Other embedded
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...

 uses of 4-bit and 8-bit microprocessors, such as terminal
Computer terminal
A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...

s, printer
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...

s, various kinds of automation
Automation
Automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and services. In the scope of industrialization, automation is a step beyond mechanization...

 etc., followed soon after. Affordable 8-bit microprocessors with 16-bit addressing also led to the first general-purpose microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...

s from the mid-1970s on.

Since the early 1970s, the increase in capacity of microprocessors has followed Moore's law
Moore's Law
Moore's law describes a long-term trend in the history of computing hardware: the number of transistors that can be placed inexpensively on an integrated circuit doubles approximately every two years....

, which suggests that the number of transistors that can be fitted onto a chip doubles every two years. Although originally calculated as a doubling every year, Moore later refined the period to two years. It is often incorrectly quoted as a doubling of transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

s every 18 months.

Embedded applications

Microprocessors make it possible to put a computer into thousands of items that were traditionally not computer-related. These include large and small household appliance
Home appliance
Home appliances are electrical/mechanical machines which accomplish some household functions, such as cooking or cleaning. Home appliances can be classified into:*Major appliances, or White goods*Small appliances, or Brown goods...

s, cars (and their accessory equipment units), car keys, tools and test instruments, toys, light switches/dimmers and electrical circuit breakers
Arc-fault circuit interrupter
An Arc Fault Circuit Interrupter is a circuit breaker designed to prevent fires by detecting a non-working electrical arc and disconnecting the power before the arc starts a fire...

, smoke alarms, battery packs, and hi-fi audio/visual components (from DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

 players to phonograph turntables.) Such products as cellular telephones, DVD video system and ATSC
ATSC
ATSC standards are a set of standards developed by the Advanced Television Systems Committee for digital television transmission over terrestrial, cable, and satellite networks....

 HDTV broadcast system fundamentally require consumer devices with powerful, low-cost, microprocessors. Increasingly stringent pollution control standards effectively require automobile manufacturers to use microprocessor engine management systems, to allow optimal control of emissions over widely varying operating conditions of an automobile. Non-programmable controls would require complex, bulky, or costly implementation to achieve the results possible with a microprocessor.

A microprocessor control program can be easily tailored to different needs of a product line, allowing upgrades in performance with minimal redesign of the product. Different features can be implemented in different models of a product line at negligible production cost.

Microprocessor control of a system can provide control strategies that would be impractical to implement using electromechanical controls or purpose-built electronic controls. For example, an engine control system in an automobile can adjust ignition timing based on engine speed, load on the engine, ambient temperature, and any observed tendency for knocking - allowing an automobile to operate on a range of fuel grades.

Structure

The internal arrangement of a microprocessor varies depending on the age of the design and the intended purposes of the processor. The complexity of an integrated circuit is bounded by physical limitations of the number of transistors that can be put onto one chip, the number of package terminations that can connect the processor to other parts of the system, the number of interconnections it is possible to make on the chip, and the heat that the chip can dissipate. Advancing technology makes more complex and powerful chips feasible to manufacture.

A minimal hypothetical microprocessor might only include an arithmetic logic unit
Arithmetic logic unit
In computing, an arithmetic logic unit is a digital circuit that performs arithmetic and logical operations.The ALU is a fundamental building block of the central processing unit of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers...

 (ALU) and a control logic section. The ALU performs operations such as addition, subtraction, and operations such as AND or OR. Each operation of the ALU sets one or more flags in a status register, which indicate the results of the last operation (zero value, negative number, overflow. or others). The logic section retrieves instruction operation codes from memory, and initiates whatever sequence of operations of the ALU required to carry out the instruction. A single operation code might affect many individual data paths, registers, and other elements of the processor.

As integrated circuit technology advanced, it was feasible to manufacture more and more complex processors on a single chip. The size of data objects became larger; allowing more transistors on a chip allowed word sizes to increase from 4- and 8-bit words up to today's 64-bit words. Additional features were added to the processor architecture; more on-chip registers speeded up programs, and complex instructions could be used to make more compact programs. Floating-point arithmetic, for example, was often not available on 8-bit microprocessors, but had to be carried out in software. Integration of the floating point unit
Floating point unit
A floating-point unit is a part of a computer system specially designed to carry out operations on floating point numbers. Typical operations are addition, subtraction, multiplication, division, and square root...

 first as a separate integrated circuit and then as part of the same microprocessor chip, speeded up floating point calculations.

Occasionally the physical limitations of integrated circuits made such practices as a bit slice
Bit slicing
Bit slicing is a technique for constructing a processor from modules of smaller bit width. Each of these components processes one bit field or "slice" of an operand...

 approach necessary. Instead of processing all of a long word on one integrated circuit, multiple circuits in parallel processed subsets of each data word. While this required extra logic to handle, for example, carry and overflow within each slice, the result was a system that could handle, say, 32-bit words using integrated circuits with a capacity for only 4 bits each.

With the ability to put large numbers of transistors on one chip, it becomes feasible to integrate memory on the same die as the processor. This CPU cache
CPU cache
A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations...

 has the advantage of faster access than off-chip memory, and increases the processing speed of the system for many applications. Generally, processor speed has increased more rapidly than external memory speed, so cache memory is necessary if the processor is not to be delayed by slower external memory.

Firsts

Three projects delivered a microprocessor at about the same time: Intel's 4004
Intel 4004
The Intel 4004 was a 4-bit central processing unit released by Intel Corporation in 1971. It was the first complete CPU on one chip, and also the first commercially available microprocessor...

, Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...

 (TI) TMS 1000, and Garrett AiResearch
Garrett AiResearch
Garrett AiResearch was a manufacturer of turboprop engines and turbochargers, and a pioneer in numerous aerospace technologies. It was previously known as Aircraft Tool and Supply Company, Garrett Supply Company, AiResearch Manufacturing Company, or simply AiResearch...

's Central Air Data Computer
Central Air Data Computer
The Central Air Data Computer is the integrated flight control system used in the early versions of the US Navy's F-14 Tomcat fighter. It is notable for its early use of a custom-designed MOS-based LSI chipset, the MP944....

 (CADC).

Intel 4004


The Intel 4004
Intel 4004
The Intel 4004 was a 4-bit central processing unit released by Intel Corporation in 1971. It was the first complete CPU on one chip, and also the first commercially available microprocessor...

 is generally regarded as the first microprocessor, and cost $60. The first known advertisement for the 4004 is dated November 15, 1971 and appeared in Electronic News
Electronic News
Electronic News was a publication that covered the semiconductor production equipment industry. It was originally a weekly trade newspaper, which covered all aspects of the electronics industry including semiconductors, computers, software, communications, space and even television...

. The project that produced the 4004 originated in 1969, when Busicom
Busicom
Busicom was a Japanese company that owned the rights to the first microprocessor, the Intel 4004, which they created in partnership with Intel in 1970....

, a Japanese calculator manufacturer, asked Intel to build a chipset for high-performance desktop calculators. Busicom's original design called for a programmable chip set consisting of seven different chips. Three of the chips were to make a special-purpose CPU with its program stored in ROM and its data stored in shift register read-write memory. Ted Hoff, the Intel engineer assigned to evaluate the project, believed the Busicom design could be simplified by using dynamic RAM storage for data, rather than shift register memory, and a more traditional general-purpose CPU architecture. Hoff came up with a four–chip architectural proposal: a ROM chip for storing the programs, a dynamic RAM chip for storing data, a simple I/O device and a 4-bit central processing unit (CPU). Although not a chip designer, he felt the CPU could be integrated into a single chip, but as he lacked the technical know-how the idea remained just a wish for the time being.

While the architecture and specifications of the MCS-4 came from the interaction of Hoff with Stanley Mazor
Stanley Mazor
Stanley Mazor is an American engineer who was born on 22 October 1941 in Chicago, Illinois. He was one of the designers of the world's first microprocessor, the Intel 4004, together with Ted Hoff, Masatoshi Shima, and Federico Faggin.-Early years:...

, a software engineer reporting to him, and with Busicom engineer Masatoshi Shima
Masatoshi Shima
is a Japanese electronics engineer, who was one of the designers of the world's first microprocessor, the Intel 4004, along with Federico Faggin, Ted Hoff, and Stanley Mazor....

, during 1969, Mazor and Hoff moved on to other projects while in April 1970, Intel hired Federico Faggin
Federico Faggin
Federico Faggin , who received in 2010 the National Medal of Technology and Innovation by Barack Obama, the highest honor bestowed by the United States government on scientists, engineers, and inventors, at the White House in Washington, is an Italian-born and naturalized U.S...

 as project leader, a move that ultimately made the single-chip CPU final design a reality (Shima instead designed the Busicom calculator firmware and assisted Faggin during the first six months of the implementation). Faggin, who originally developed the silicon gate technology (SGT) in 1968 at Fairchild Semiconductor and designed the world’s first commercial integrated circuit using SGT, the Fairchild 3708, had the correct background to lead the project into what would become the first commercial general purpose microprocessor, since it was his very own invention, SGT in addition to his new methodology for random logic design, that made it possible to implement a single-chip CPU with the proper speed, power dissipation and cost.
The manager of Intel's MOS Design Department was Leslie L. Vadász. at the time of the MCS-4 development, but Vadasz's attention was completely focused on the mainstream business of semiconductor memories and he left the leadership and the management of the MCS-4 project to Faggin, which was ultimately responsible for leading the 4004 project to its outcome. Production units of the 4004 were first delivered to Busicom in March 1971 and shipped to other customers in late 1971.

TMS 1000

The Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...

 says TI
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...

 engineers Gary Boone and Michael Cochran succeeded in creating the first microcontroller (also called a microcomputer) in 1971. The result of their work was the TMS 1000, which went commercial in 1974.

TI developed the 4-bit TMS 1000 and stressed pre-programmed embedded applications, introducing a version called the TMS1802NC on September 17, 1971 which implemented a calculator on a chip.

TI filed for the patent on the microprocessor. Gary Boone was awarded for the single-chip microprocessor architecture on September 4, 1973. It may never be known which company actually had the first working microprocessor running on the lab bench. In both 1971 and 1976, Intel and TI entered into broad patent cross-licensing agreements, with Intel paying royalties to TI for the microprocessor patent. A history of these events is contained in court documentation from a legal dispute between Cyrix and Intel, with TI as intervenor and owner of the microprocessor patent.

A computer-on-a-chip combines the microprocessor core (CPU), memory, and I/O (input/output
Input/output
In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...

) lines onto one chip
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

. The computer-on-a-chip patent, called the "microcomputer patent" at the time, , was awarded to Gary Boone and Michael J. Cochran of TI. Aside from this patent, the standard meaning of microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...

 is a computer using one or more microprocessors as its CPU(s), while the concept defined in the patent is more akin to a microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...

.

Pico/General Instrument

In 1971 Pico Electronics and General Instrument
General Instrument
General Instrument was an electronics manufacturer based in Horsham, PA specializing in semiconductors and cable television equipment. The company was active until 1997, when it split into which was later acquired by Vishay Intertechnology in 2001, CommScope and NextLevel Systems General...

 (GI) introduced their first collaboration in ICs, a complete single chip calculator IC for the Monroe/Litton Royal Digital III calculator. This chip could also arguably lay claim to be one of the first microprocessors or microcontrollers having ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...

, RAM
Random-access memory
Random access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...

 and a RISC instruction set on-chip. The layout for the four layers of the PMOS
PMOS logic
P-type metal-oxide-semiconductor logic uses p-type metal-oxide-semiconductor field effect transistors to implement logic gates and other digital circuits...

 process was hand drawn at x500 scale on mylar film, a significant task at the time given the complexity of the chip.

Pico was a spinout by five GI design engineers whose vision was to create single chip calculator ICs. They had significant previous design experience on multiple calculator chipsets with both GI and Marconi-Elliott. The key team members had originally been tasked by Elliott Automation to create an 8 bit computer in MOS and had helped establish a MOS Research Laboratory in Glenrothes
Glenrothes
Glenrothes is a large town situated in the heart of Fife, in east-central Scotland. It is located approximately from both Edinburgh, which lies to the south and Dundee to the north. The town had an estimated population of 38,750 in 2008, making Glenrothes the third largest settlement in Fife...

, Scotland in 1967.

Calculators were becoming the largest single market for semiconductors and Pico and GI went on to have significant success in this burgeoning market. GI continued to innovate in microprocessors and microcontrollers with products including the CP1600, IOB1680 and PIC1650. In 1987 the GI Microelectronics business was spun out into the Microchip
Microchip
Microchip can also refer to:* Integrated circuit, a set of electronic components on a single unit.* Microchip Technology, a company that makes popular 8, 16 and 32-bit microcontroller lines.* Microchip implant , a microchip implanted into animals....

 PIC microcontroller
PIC microcontroller
PIC is a family of Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC1650 originally developed by General Instrument's Microelectronics Division...

 business.

CADC

In 1968, Garrett AiResearch
Garrett AiResearch
Garrett AiResearch was a manufacturer of turboprop engines and turbochargers, and a pioneer in numerous aerospace technologies. It was previously known as Aircraft Tool and Supply Company, Garrett Supply Company, AiResearch Manufacturing Company, or simply AiResearch...

 (which employed designers Ray Holt
Ray holt
Raymond M. Holt was a pioneering computer designer and businessman in Silicon Valley.From 1968-1970, Holt developed the first microprocessor chip set for Garrett AiResearch's Central Air Data Computer for the F-14 Tomcat....

 and Steve Geller) was invited to produce a digital computer to compete with electromechanical systems then under development for the main flight control computer in the US Navy's new F-14 Tomcat
F-14 Tomcat
The Grumman F-14 Tomcat is a supersonic, twin-engine, two-seat, variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy's Naval Fighter Experimental program following the collapse of the F-111B project...

 fighter. The design was complete by 1970, and used a MOS
MOSFET
The metal–oxide–semiconductor field-effect transistor is a transistor used for amplifying or switching electronic signals. The basic principle of this kind of transistor was first patented by Julius Edgar Lilienfeld in 1925...

-based chipset as the core CPU. The design was significantly (approximately 20 times) smaller and much more reliable than the mechanical systems it competed against, and was used in all of the early Tomcat models. This system contained "a 20-bit, pipelined, parallel multi-microprocessor". The Navy refused to allow publication of the design until 1997. For this reason the CADC
Central Air Data Computer
The Central Air Data Computer is the integrated flight control system used in the early versions of the US Navy's F-14 Tomcat fighter. It is notable for its early use of a custom-designed MOS-based LSI chipset, the MP944....

, and the MP944 chipset it used, are fairly unknown.
Ray Holt graduated California Polytechnic University
California Polytechnic State University
California Polytechnic State University, or Cal Poly, is a public university located in San Luis Obispo, California, United States. The university is one of two polytechnic campuses in the 23-member California State University system....

 in 1968, and began his computer design career with the CADC. From its inception, it was shrouded in secrecy until 1998 when at Holt's request, the US Navy allowed the documents into the public domain. Since then several have debated if this was the first microprocessor. Holt has stated that no one has compared this microprocessor with those that came later. According to Parab et al. (2007), "The scientific papers and literature published around 1971 reveal that the MP944
Central Air Data Computer
The Central Air Data Computer is the integrated flight control system used in the early versions of the US Navy's F-14 Tomcat fighter. It is notable for its early use of a custom-designed MOS-based LSI chipset, the MP944....

 digital processor used for the F-14 Tomcat
F-14 Tomcat
The Grumman F-14 Tomcat is a supersonic, twin-engine, two-seat, variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy's Naval Fighter Experimental program following the collapse of the F-111B project...

 aircraft of the US Navy qualifies as the first microprocessor. Although interesting, it was not a single-chip processor, and was not general purpose – it was more like a set of parallel building blocks you could use to make a special-purpose DSP
Digital signal processor
A digital signal processor is a specialized microprocessor with an architecture optimized for the fast operational needs of digital signal processing.-Typical characteristics:...

 form. It indicates that today’s industry theme of converging DSP-microcontroller architectures was started in 1971." This convergence of DSP and microcontroller architectures is known as a Digital Signal Controller
Digital signal controller
A digital signal controller can be thought of as a hybrid of microcontrollers and digital signal processors . Like microcontrollers, DSCs have fast interrupt responses, offer control-oriented peripherals like PWMs and watchdog timers, and are usually programmed using the C programming language,...

.

Gilbert Hyatt

Gilbert Hyatt was awarded a patent claiming an invention pre-dating both TI and Intel, describing a "microcontroller". The patent was later invalidated, but not before substantial royalties were paid out.

Four-Phase Systems AL1

The Four-Phase Systems AL1 was an 8-bit bit slice chip containing eight registers and an ALU. It was designed by Lee Boysel in 1969. At the time, it formed part of a nine-chip, 24-bit CPU with three AL1s, but it was later called a microprocessor when, in response to 1990s litigation by Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...

, a demonstration system was constructed where a single AL1 formed part of a courtroom demonstration computer system, together with RAM, ROM, and an input-output device.

8-bit designs

The Intel 4004 was followed in 1972 by the Intel 8008
Intel 8008
The Intel 8008 was an early byte-oriented microprocessor designed and manufactured by Intel and introduced in April 1972. It was an 8-bit CPU with an external 14-bit address bus that could address 16KB of memory...

, the world's first 8-bit
8-bit
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 and the Motorola 6800 were also used in similar computers...

 microprocessor. The 8008 was not, however, an extension of the 4004 design, but instead the culmination of a separate design project at Intel, arising from a contract with Computer Terminals Corporation
Datapoint
Datapoint Corporation, originally known as Computer Terminal Corporation , was a computer company based in San Antonio, Texas, United States. Founded in 1967 by Phil Ray and Gus Roche, its first products were, as the company's initial name suggests, computer terminals...

, of San Antonio TX, for a chip for a terminal they were designing, the Datapoint 2200
Datapoint 2200
The Datapoint 2200 was a mass-produced programmable terminal, designed by Phil Ray and Gus Roche, announced by Computer Terminal Corporation in June, 1970...

 — fundamental aspects of the design came not from Intel but from CTC. In 1968, CTC's Austin O. “Gus” Roche developed the original design for the instruction set and operation of the processor. In 1969, CTC contracted two companies, Intel and Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...

, to make a single-chip implementation, known as the CTC 1201. In late 1970 or early 1971, TI dropped out being unable to make a reliable part. In 1970, with Intel yet to deliver the part, CTC opted to use their own implementation in the Datapoint 3300, using traditional TTL logic instead (thus the first machine to run “8008 code” was not in fact a microprocessor at all). Intel's version of the 1201 microprocessor arrived in late 1971, but was too late, slow, and required a number of additional support chips. CTC had no interest in using it. CTC had originally contracted Intel for the chip, and would have owed them $50,000 for their design work. To avoid paying for a chip they did not want (and could not use), CTC released Intel from their contract and allowed them free use of the design. Intel marketed it as the 8008 in April, 1972, as the world's first 8-bit microprocessor. It was the basis for the famous "Mark-8
Mark-8
The Mark-8 is a microcomputer design from 1974, based on the Intel 8008 CPU . The Mark-8 was designed by graduate student Jonathan Titus and announced as a 'loose kit' in the July 1974 issue of Radio-Electronics magazine.- Project kit :The Mark-8 was introduced as a 'build it yourself' project in...

" computer kit advertised in the magazine Radio-Electronics
Radio-Electronics
Radio-Electronics was an American electronics magazine that was published under various titles from 1929 to 2003. Hugo Gernsback started it as Radio-Craft in July 1929. The title was changed to Radio-Electronics in October 1948 and again to Electronics Now in July 1992. In January 2000 it was...

in 1974.

The 8008 was the precursor to the very successful Intel 8080
Intel 8080
The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...

 (1974), which offered much improved performance over the 8008 and required fewer support chips, Zilog Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...

 (1976), and derivative Intel 8-bit processors. The competing Motorola 6800
Motorola 6800
The 6800 was an 8-bit microprocessor designed and first manufactured by Motorola in 1974. The MC6800 microprocessor was part of the M6800 Microcomputer System that also included serial and parallel interface ICs, RAM, ROM and other support chips...

 was released August 1974 and the similar MOS Technology 6502
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...

 in 1975 (designed largely by the same people). The 6502 rivaled the Z80 in popularity during the 1980s.

A low overall cost, small packaging, simple computer bus
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...

 requirements, and sometimes the integration of extra circuitry (e.g. the Z80's built-in memory refresh
Memory refresh
Memory refresh is the process of periodically reading information from an area of computer memory, and immediately rewriting the read information to the same area with no modifications. Each memory refresh cycle refreshes a succeeding area of memory. Memory refresh is most often associated with...

 circuitry) allowed the home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...

 "revolution" to accelerate sharply in the early 1980s. This delivered such inexpensive machines as the Sinclair ZX-81, which sold for US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

99.

The Western Design Center, Inc.
Western Design Center
The Western Design Center , located in Mesa, Arizona, USA, is a company developing and manufacturing MOS 65xx-based microprocessors, microcontrollers , and related support chips...

 (WDC) introduced the CMOS 65C02 in 1982 and licensed the design to several firms. It was used as the CPU in the Apple IIe
Apple IIe
The Apple IIe is the third model in the Apple II series of personal computers produced by Apple Computer. The e in the name stands for enhanced, referring to the fact that several popular features were now built-in that were only available as upgrades and add-ons in earlier models...

 and IIc
Apple IIc
The Apple IIc, the fourth model in the Apple II series of personal computers, was Apple Computer’s first endeavor to produce a portable computer. The end result was a notebook-sized version of the Apple II that could be transported from place to place...

 personal computers as well as in medical implantable grade pacemakers and defibrillators, automotive, industrial and consumer devices. WDC pioneered the licensing of microprocessor designs, later followed by ARM
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...

 and other microprocessor Intellectual Property
Intellectual property
Intellectual property is a term referring to a number of distinct types of creations of the mind for which a set of exclusive rights are recognized—and the corresponding fields of law...

 (IP) providers in the 1990s. A variation of the 6502, the MOS Technology 6510
MOS Technology 6510
thumb|300px|Image of the internals of a [[Commodore 64]] showing the 6510 CPU . The chip on the right is the [[MOS Technology SID|6581 SID]]...

 was used in the Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...

 and Commodore 128
Commodore 128
The Commodore 128 home/personal computer was the last 8-bit machine commercially released by Commodore Business Machines...

 home computers.

Motorola introduced the MC6809
Motorola 6809
The Motorola 6809 is an 8-bit microprocessor CPU from Motorola, designed by Terry Ritter and Joel Boney and introduced 1978...

 in 1978, an ambitious and thought-through 8-bit design source compatible with the 6800 and implemented using purely hard-wired logic. (Subsequent 16-bit microprocessors typically used microcode
Microcode
Microcode is a layer of hardware-level instructions and/or data structures involved in the implementation of higher level machine code instructions in many computers and other processors; it resides in special high-speed memory and translates machine instructions into sequences of detailed...

 to some extent, as CISC design requirements were getting too complex for purely hard-wired logic only.)

Another early 8-bit microprocessor was the Signetics 2650
Signetics 2650
The Signetics 2650, was a very early 8-bit microprocessor. According to Adam Osborne's classic book An Introduction to Microprocessors Vol 2: Some Real Products, it was "the most minicomputer-like" of the microprocessors available at the time....

, which enjoyed a brief surge of interest due to its innovative and powerful instruction set
Instruction set
An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...

 architecture.

A seminal microprocessor in the world of spaceflight was RCA's RCA 1802
RCA 1802
The RCA CDP1802, also known as the COSMAC , is an 8-bit CMOS microprocessor introduced by RCA in early 1976. It is being by Intersil Corporation as a high-reliability microprocessor...

 (aka CDP1802, RCA COSMAC) (introduced in 1976), which was used onboard the Galileo
Galileo spacecraft
Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. Named after the astronomer and Renaissance pioneer Galileo Galilei, it was launched on October 18, 1989 by the Space Shuttle Atlantis on the STS-34 mission...

 probe to Jupiter (launched 1989, arrived 1995). RCA COSMAC was the first to implement CMOS
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...

 technology. The CDP1802 was used because it could be run at very low power
Low-power electronics
Low-power electronics means that the consumption of electric power is deliberately low, e.g. notebook processors.- Computing elements :The density and speed of integrated-circuit computing elements have increased exponentially for several decades, following a trend described by Moore's Law...

, and because a variant was available fabricated using a special production process (Silicon on Sapphire
Silicon on sapphire
Silicon on sapphire is a hetero-epitaxial process for integrated circuit manufacturing that consists of a thin layer of silicon grown on a sapphire wafer. SOS is part of the Silicon on Insulator family of CMOS technologies...

), providing much better protection against cosmic radiation and electrostatic discharge
Electrostatic discharge
Electrostatic discharge is a serious issue in solid state electronics, such as integrated circuits. Integrated circuits are made from semiconductor materials such as silicon and insulating materials such as silicon dioxide...

s than that of any other processor of the era. Thus, the SOS version of the 1802 was said to be the first radiation-hardened microprocessor.

The RCA 1802
RCA 1802
The RCA CDP1802, also known as the COSMAC , is an 8-bit CMOS microprocessor introduced by RCA in early 1976. It is being by Intersil Corporation as a high-reliability microprocessor...

 had what is called a static design, meaning that the clock frequency could be made arbitrarily low, even to 0 Hz, a total stop condition. This let the Galileo spacecraft
Galileo spacecraft
Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. Named after the astronomer and Renaissance pioneer Galileo Galilei, it was launched on October 18, 1989 by the Space Shuttle Atlantis on the STS-34 mission...

 use minimum electric power for long uneventful stretches of a voyage. Timers and/or sensors would awaken/improve the performance of the processor in time for important tasks, such as navigation updates, attitude control, data acquisition, and radio communication.

12-bit designs

The Intersil 6100
Intersil 6100
The Intersil 6100 family consisted of a 12-bit microprocessor and a range of peripheral support and memory ICs developed in the mid-1970s.The microprocessor recognised the PDP-8 instruction set....

 family consisted of a 12-bit
12-bit
Possibly the best-known 12-bit CPU is the PDP-8 and its relatives, produced in various incarnations from August 1963 to mid-1990. Many ADCs have a 12-bit resolution. Some PIC microcontrollers use a 12-bit word size....

 microprocessor (the 6100) and a range of peripheral support and memory ICs. The microprocessor recognised the DEC PDP-8
PDP-8
The 12-bit PDP-8 was the first successful commercial minicomputer, produced by Digital Equipment Corporation in the 1960s. DEC introduced it on 22 March 1965, and sold more than 50,000 systems, the most of any computer up to that date. It was the first widely sold computer in the DEC PDP series of...

 minicomputer
Minicomputer
A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...

 instruction set. As such it was sometimes referred to as the CMOS-PDP8. Since it was also produced by Harris Corporation, it was also known as the Harris HM-6100. By virtue of its CMOS technology and associated benefits, the 6100 was being incorporated into some military designs until the early 1980s.

16-bit designs

The first multi-chip 16-bit
16-bit
-16-bit architecture:The HP BPC, introduced in 1975, was the world's first 16-bit microprocessor. Prominent 16-bit processors include the PDP-11, Intel 8086, Intel 80286 and the WDC 65C816. The Intel 8088 was program-compatible with the Intel 8086, and was 16-bit in that its registers were 16...

 microprocessor was the National Semiconductor
National Semiconductor
National Semiconductor was an American semiconductor manufacturer, that specialized in analog devices and subsystems,formerly headquartered in Santa Clara, California, USA. The products of National Semiconductor included power management circuits, display drivers, audio and operational amplifiers,...

 IMP-16
IMP-16
The IMP-16, by National Semiconductor, was the first multi-chip 16-bit microprocessor. It consisted of five PMOS integrated circuits: four four-bit RALU chips providing the data path, and one CROM providing control sequencing and microcode storage.The IMP-16 provided four 16-bit accumulators,...

, introduced in early 1973. An 8-bit version of the chipset was introduced in 1974 as the IMP-8.

Other early multi-chip 16-bit microprocessors include one used by Digital Equipment Corporation (DEC)
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

 in the LSI-11 OEM board set and the packaged PDP 11/03
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...

 minicomputer
Minicomputer
A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...

, and the Fairchild Semiconductor
Fairchild Semiconductor
Fairchild Semiconductor International, Inc. is an American semiconductor company based in San Jose, California. Founded in 1957, it was a pioneer in transistor and integrated circuit manufacturing...

 MicroFlame 9440, both of which were introduced in the 1975 to 1976 timeframe.

In 1975, National introduced the first 16-bit single-chip microprocessor, the National Semiconductor PACE
National Semiconductor PACE
National Semiconductor's IPC-16A/520 PACE, short for "Processing and Control Element", was the first commercial single-chip 16-bit microprocessor...

, which was later followed by an NMOS
NMOS logic
N-type metal-oxide-semiconductor logic uses n-type metal-oxide-semiconductor field effect transistors to implement logic gates and other digital circuits...

 version, the INS8900.

Another early single-chip 16-bit microprocessor was TI's TMS 9900
Texas Instruments TMS9900
Introduced in June 1976 and based on the Texas Instruments 990 minicomputer CPU, the TMS9900 was one of the first true 16-bit microprocessors...

, which was also compatible with their TI-990
TI-990
The TI-990 was a series of 16-bit minicomputers sold by Texas Instruments in the 1970s and 1980s. The TI-990 was a replacement for TI's earlier minicomputer systems, the TI-960 and the TI-980...

 line of minicomputers. The 9900 was used in the TI 990/4 minicomputer, the TI-99/4A home computer, and the TM990 line of OEM microcomputer boards. The chip was packaged in a large ceramic 64-pin DIP package
Dual in-line package
In microelectronics, a dual in-line package is an electronic device package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board or inserted in a socket.A DIP is usually referred to as a DIPn, where n is...

, while most 8-bit microprocessors such as the Intel 8080 used the more common, smaller, and less expensive plastic 40-pin DIP. A follow-on chip, the TMS 9980, was designed to compete with the Intel 8080, had the full TI 990 16-bit instruction set, used a plastic 40-pin package, moved data 8 bits at a time, but could only address 16 KB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...

. A third chip, the TMS 9995, was a new design. The family later expanded to include the 99105 and 99110.

The Western Design Center
Western Design Center
The Western Design Center , located in Mesa, Arizona, USA, is a company developing and manufacturing MOS 65xx-based microprocessors, microcontrollers , and related support chips...

 (WDC) introduced the CMOS 65816
WDC 65816/65802
The W65C816S is a 16-bit microprocessor developed by the Western Design Center . The W65C816S is an enhanced version of the WDC 65C02 8-bit MPU, itself a CMOS enhancement of the venerable MOS Technology 6502 NMOS MPU...

 16-bit upgrade of the WDC CMOS 65C02
WDC 65C02
The Western Design Center WDC 65C02 microprocessor is an upgraded CMOS version of the popular NMOS-based MOS Technology 6502 8-bit CPU — the CMOS redesign being made by Bill Mensch of the Western Design Center...

 in 1984. The 65816 16-bit microprocessor was the core of the Apple IIgs
Apple IIGS
The Apple , the fifth and most powerful model in the Apple II series of personal computers produced by Apple Computer. The "GS" in the name stands for Graphics and Sound, referring to its enhanced graphics and sound capabilities, both of which greatly surpassed previous models of the line...

 and later the Super Nintendo Entertainment System
Super Nintendo Entertainment System
The Super Nintendo Entertainment System is a 16-bit video game console that was released by Nintendo in North America, Europe, Australasia , and South America between 1990 and 1993. In Japan and Southeast Asia, the system is called the , or SFC for short...

, making it one of the most popular 16-bit designs of all time.

Intel "upsized" their 8080 design into the 16-bit Intel 8086
Intel 8086
The 8086 is a 16-bit microprocessor chip designed by Intel between early 1976 and mid-1978, when it was released. The 8086 gave rise to the x86 architecture of Intel's future processors...

, the first member of the x86 family, which powers most modern PC
IBM PC compatible
IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...

 type computers. Intel introduced the 8086 as a cost effective way of porting software from the 8080 lines, and succeeded in winning much business on that premise. The 8088
Intel 8088
The Intel 8088 microprocessor was a variant of the Intel 8086 and was introduced on July 1, 1979. It had an 8-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers and the one megabyte address range were unchanged, however...

, a version of the 8086 that used an 8-bit external data bus, was the microprocessor in the first IBM PC
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...

. Intel then released the 80186 and 80188, the 80286
Intel 80286
The Intel 80286 , introduced on 1 February 1982, was a 16-bit x86 microprocessor with 134,000 transistors. Like its contemporary simpler cousin, the 80186, it could correctly execute most software written for the earlier Intel 8086 and 8088...

 and, in 1985, the 32-bit 80386
Intel 80386
The Intel 80386, also known as the i386, or just 386, was a 32-bit microprocessor introduced by Intel in 1985. The first versions had 275,000 transistors and were used as the central processing unit of many workstations and high-end personal computers of the time...

, cementing their PC market dominance with the processor family's backwards compatibility. The 80186 and 80188 were essentially versions of the 8086 and 8088, enhanced with some onboard peripherals and a few new instructions; they were not used in IBM-compatible PCs because the built-in perpherals and their locations in the memory map were incompatible with the IBM design. The 8086 and successors had an innovative but limited method of memory segmentation, while the 80286 introduced a full-featured segmented memory management unit
Memory management unit
A memory management unit , sometimes called paged memory management unit , is a computer hardware component responsible for handling accesses to memory requested by the CPU...

 (MMU). The 80386 introduced a flat 32-bit memory model with paged memory management.

The Intel x86 processors up to and including the 80386 do not include floating-point units (FPUs). Intel introduced the 8087
Intel 8087
The Intel 8087, announced in 1980, was the first floating-point coprocessor for the 8086 line of microprocessors. It had 45,000 transistors and was manufactured as a 3 μm depletion load HMOS circuit. The 8087 was built to be paired with the Intel 8088 or 8086 microprocessors...

, 80287, and 80387 math coprocessors to add hardware floating-point and transcendental function capabilities to the 8086 through 80386 CPUs. The 8087 works with the 8086/8088 and 80186/80188, the 80187 works with the 80186/80188, the 80287 works with the 80286 and 80386, and the 80387 works with the 80386 (yielding better performance than the 80287). The combination of an x86 CPU and an x87 coprocessor forms a single multi-chip microprocessor; the two chips are programmed as a unit using a single integrated instruction set. Though the 8087 coprocessor is interfaced to the CPU through I/O ports in the CPU's address space, this is transparent to the program, which does not need to know about or access these I/O ports directly; the program accesses the coprocessor and its registers through normal instruction opcodes. Starting with the successor to the 80386, the 80486
Intel 80486
The Intel 80486 microprocessor was a higher performance follow up on the Intel 80386. Introduced in 1989, it was the first tightly pipelined x86 design as well as the first x86 chip to use more than a million transistors, due to a large on-chip cache and an integrated floating point unit...

, the FPU was integrated with the control unit, MMU, and integer ALU in a pipelined design on a single chip (in the 80486DX version), or the FPU was eliminated entirely (in the 80486SX version). An ostensible coprocessor for the 80486SX, the 80487, was actually a complete 80486DX which disabled and replaced the coprocessorless 80486SX that it was installed to upgrade.

32-bit designs

16-bit designs had only been on the market briefly when 32-bit implementations started to appear.

The most significant of the 32-bit designs is the MC68000
Motorola 68000
The Motorola 68000 is a 16/32-bit CISC microprocessor core designed and marketed by Freescale Semiconductor...

, introduced in 1979. The 68K, as it was widely known, had 32-bit registers in its programming model but used 16-bit internal data paths, 3 16-bit Arithmetic Logic Units, and a 16-bit external data bus (to reduce pin count), and supported only 24-bit addresses. In PC-based IBM-compatible mainframes
PC-based IBM-compatible mainframes
Since the rise of the personal computer in the 1980s, IBM and other vendors have created PC-based IBM-compatible mainframes which are compatible with the larger IBM mainframe computers. For a period of time PC-based mainframe-compatible systems had a lower price and did not require as much...

 the MC68000 internal microcode was modified to emulate the 32-bit System/370 IBM mainframe. Motorola generally described it as a 16-bit processor, though it clearly has 32-bit capable architecture
Computer architecture
In computer science and engineering, computer architecture is the practical art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals and the formal modelling of those systems....

. The combination of high performance, large (16 megabyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...

s or 224 bytes) memory space and fairly low cost made it the most popular CPU design of its class. The Apple Lisa
Apple Lisa
The Apple Lisa—also known as the Lisa—is a :personal computer designed by Apple Computer, Inc. during the early 1980s....

 and Macintosh designs made use of the 68000, as did a host of other designs in the mid-1980s, including the Atari ST
Atari ST
The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...

 and Commodore Amiga.

The world's first single-chip fully 32-bit microprocessor, with 32-bit data paths, 32-bit buses, and 32-bit addresses, was the AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

 Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...

 BELLMAC-32A, with first samples in 1980, and general production in 1982 After the divestiture of AT&T
Bell System divestiture
The Bell System divestiture, or the breakup of AT&T, was initiated by the filing in 1974 by the U.S. Department of Justice of an antitrust lawsuit against AT&T. The case, United States v...

 in 1984, it was renamed the WE 32000 (WE for Western Electric
Western Electric
Western Electric Company was an American electrical engineering company, the manufacturing arm of AT&T from 1881 to 1995. It was the scene of a number of technological innovations and also some seminal developments in industrial management...

), and had two follow-on generations, the WE 32100 and WE 32200. These microprocessors were used in the AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

 3B5 and 3B15 minicomputers; in the 3B2, the world's first desktop supermicrocomputer; in the "Companion", the world's first 32-bit laptop computer; and in "Alexander", the world's first book-sized supermicrocomputer, featuring ROM-pack memory cartridges similar to today's gaming consoles. All these systems ran the UNIX System V
UNIX System V
Unix System V, commonly abbreviated SysV , is one of the first commercial versions of the Unix operating system. It was originally developed by American Telephone & Telegraph and first released in 1983. Four major versions of System V were released, termed Releases 1, 2, 3 and 4...

 operating system.

Intel's first 32-bit microprocessor was the iAPX 432
Intel iAPX 432
The Intel iAPX 432 was a commercially unsuccessful 32-bit microprocessor architecture, introduced in 1981.The project was Intel's first 32-bit microprocessor design, and intended to be the company's main product line for the 1980s. Many advanced multitasking and memory management features were...

, which was introduced in 1981 but was not a commercial success. It had an advanced capability-based
Capability-based security
Capability-based security is a concept in the design of secure computing systems, one of the existing security models. A capability is a communicable, unforgeable token of authority. It refers to a value that references an object along with an associated set of access rights...

 object-oriented
Object (computer science)
In computer science, an object is any entity that can be manipulated by the commands of a programming language, such as a value, variable, function, or data structure...

 architecture, but poor performance compared to contemporary architectures such as Intel's own 80286 (introduced 1982), which was almost four times as fast on typical benchmark tests. However, the results for the iAPX432 was partly due to a rushed and therefore suboptimal Ada
Ada (programming language)
Ada is a structured, statically typed, imperative, wide-spectrum, and object-oriented high-level computer programming language, extended from Pascal and other languages...

 compiler
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...

.

The ARM
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...

 first appeared in 1985. This is a RISC processor design, which has since come to dominate the 32-bit embedded systems processor space due in large part to its power efficiency, its licensing model, and its wide selection of system development tools. Semiconductor manufacturers generally license cores such as the ARM11
ARM11
ARM11 is an ARM architecture 32-bit RISC microprocessor family which introduced the ARMv6 architectural additions. These include SIMD media instructions, multiprocessor support and a new cache architecture...

 and integrate them into their own system on a chip products; only a few such vendors are licensed to modify the ARM cores. Most cell phones include an ARM processor, as do a wide variety of other products. There are microcontroller-oriented ARM cores without virtual memory support, as well as SMP
SMP
-In technology:* Shape memory polymers, in the field of chemical engineering.* Simulation Model Portability: A standard developed by ESA and ECSS for space mission simulators....

 applications processors with virtual memory.

Motorola's success with the 68000 led to the MC68010
Motorola 68010
The Motorola MC68010 processor is a 16/32-bit microprocessor from Motorola, released in 1982. In line with the Motorola 68000 naming convention, it is usually just referred to as the 010 ....

, which added virtual memory support. The MC68020
Motorola 68020
The Motorola 68020 is a 32-bit microprocessor from Motorola, released in 1984. It is the successor to the Motorola 68010 and is succeeded by the Motorola 68030...

, introduced in 1985 added full 32-bit data and address buses. The 68020 became hugely popular in the Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 supermicrocomputer market, and many small companies (e.g., Altos, Charles River Data Systems) produced desktop-size systems. The MC68030
Motorola 68030
The Motorola 68030 is a 32-bit microprocessor in Motorola's 68000 family. It was released in 1987. The 68030 was the successor to the Motorola 68020, and was followed by the Motorola 68040. In keeping with general Motorola naming, this CPU is often referred to as the 030 .The 68030 features on-chip...

 was introduced next, improving upon the previous design by integrating the MMU into the chip. The continued success led to the MC68040
Motorola 68040
The Motorola 68040 is a microprocessor from Motorola, released in 1990. It is the successor to the 68030 and is followed by the 68060. There was no 68050. In keeping with general Motorola naming, the 68040 is often referred to as simply the '040 ....

, which included an FPU
Floating point unit
A floating-point unit is a part of a computer system specially designed to carry out operations on floating point numbers. Typical operations are addition, subtraction, multiplication, division, and square root...

 for better math performance. A 68050 failed to achieve its performance goals and was not released, and the follow-up MC68060
Motorola 68060
The Motorola 68060 is a 32-bit microprocessor from Motorola released in 1994. It is the successor to the Motorola 68040 and is the highest performing member of the 680x0 family. Two derivatives were produced, the 68LC060 and the 68EC060....

 was released into a market saturated by much faster RISC designs. The 68K family faded from the desktop in the early 1990s.

Other large companies designed the 68020 and follow-ons into embedded equipment. At one point, there were more 68020s in embedded equipment than there were Intel Pentiums in PCs. The ColdFire processor cores are derivatives of the venerable 68020.

During this time (early to mid-1980s), National Semiconductor
National Semiconductor
National Semiconductor was an American semiconductor manufacturer, that specialized in analog devices and subsystems,formerly headquartered in Santa Clara, California, USA. The products of National Semiconductor included power management circuits, display drivers, audio and operational amplifiers,...

 introduced a very similar 16-bit pinout, 32-bit internal microprocessor called the NS 16032 (later renamed 32016), the full 32-bit version named the NS 32032
NS320xx
The 320xx or NS32000 was a series of microprocessors from National Semiconductor . They were likely the first 32-bit general-purpose microprocessors on the market, but due to a number of factors never managed to become a major player...

. Later the NS 32132
NS320xx
The 320xx or NS32000 was a series of microprocessors from National Semiconductor . They were likely the first 32-bit general-purpose microprocessors on the market, but due to a number of factors never managed to become a major player...

 was introduced which allowed two CPUs to reside on the same memory bus, with built in arbitration. The NS32016/32 outperformed the MC68000/10 but the NS32332 which arrived at approximately the same time the MC68020 did not have enough performance. The third generation chip, the NS32532 was different. It had about double the performance of the MC68030 which was released around the same time. The appearance of RISC processors like the AM29000 and MC88000 (now both dead) influenced the architecture of the final core, the NS32764. Technically advanced, using a superscalar RISC core, internally overclocked, with a 64 bit bus, it was still capable of executing Series 32000 instructions through real time translation.

When National Semiconductor decided to leave the Unix market, the chip was redesigned into the Swordfish Embedded processor with a set of on chip peripherals. The chip turned out to be too expensive for the laser printer
Laser printer
A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers , laser printers employ a xerographic printing process, but differ from analog photocopiers in that the image is produced...

  market and was killed. The design team went to Intel and there designed the Pentium processor which is very similar to the NS32764 core internally The big success of the Series 32000 was in the laser printer market, where the NS32CG16 with microcoded BitBlt instructions had very good price/performance and was adopted by large companies like Canon. By the mid-1980s, Sequent
Sequent Computer Systems
Sequent Computer Systems, or Sequent, was a computer company that designed and manufactured multiprocessing computer systems. They were among the pioneers in high-performance symmetric multiprocessing open systems, innovating in both hardware and software Sequent Computer Systems, or Sequent, was...

 introduced the first symmetric multiprocessor (SMP) server-class computer using the NS 32032. This was one of the design's few wins, and it disappeared in the late 1980s. The MIPS
MIPS architecture
MIPS is a reduced instruction set computer instruction set architecture developed by MIPS Technologies . The early MIPS architectures were 32-bit, and later versions were 64-bit...

 R2000
R2000 (microprocessor)
The R2000 is a microprocessor chip set developed by MIPS Computer Systems that implemented the MIPS I instruction set architecture . Introduced in January 1986, it was the first commercial implementation of the MIPS architecture and the first merchant RISC processor available to all companies...

 (1984) and R3000
R3000
The R3000 is a microprocessor chip set developed by MIPS Computer Systems that implemented the MIPS I instruction set architecture . Introduced in June 1988, it was the second MIPS implementation, succeeding the R2000 as the flagship MIPS microprocessor...

 (1989) were highly successful 32-bit RISC microprocessors. They were used in high-end workstations and servers by SGI
Silicon Graphics
Silicon Graphics, Inc. was a manufacturer of high-performance computing solutions, including computer hardware and software, founded in 1981 by Jim Clark...

, among others. Other designs included the interesting Zilog Z80000
Zilog Z80000
The Z80000 is Zilog's 32-bit processor from 1986, an expansion of its 16-bit predecessor, the Zilog Z8000. It includes multiprocessing capability, a six-stage instruction pipeline, and a 256-byte cache. Its memory addressing system can access 4 gigabytes of RAM. Described at the time as a...

, which arrived too late to market to stand a chance and disappeared quickly.

In the late 1980s, "microprocessor wars" started killing off some of the microprocessors. Apparently, with only one major design win, Sequent, the NS 32032 just faded out of existence, and Sequent switched to Intel microprocessors.

From 1985 to 2003, the 32-bit x86 architectures became increasingly dominant in desktop, laptop, and server markets, and these microprocessors became faster and more capable. Intel had licensed early versions of the architecture to other companies, but declined to license the Pentium, so AMD and Cyrix
Cyrix
Cyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas as a specialist supplier of high-performance math coprocessors for 286 and 386 microprocessors. The company was founded by former Texas Instruments staff members and had a long but troubled relationship...

 built later versions of the architecture based on their own designs. During this span, these processors increased in complexity (transistor count) and capability (instructions/second) by at least three orders of magnitude. Intel's Pentium line is probably the most famous and recognizable 32-bit processor model, at least with the public at large.

64-bit designs in personal computers

While 64-bit microprocessor designs have been in use in several markets since the early 1990s, the early 2000s saw the introduction of 64-bit microprocessors targeted at the PC market.

With AMD's introduction of a 64-bit architecture backwards-compatible with x86, x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

 (also called AMD64), in September 2003, followed by Intel's near fully compatible 64-bit extensions (first called IA-32e or EM64T, later renamed Intel 64), the 64-bit desktop era began. Both versions can run 32-bit legacy applications without any performance penalty as well as new 64-bit software. With operating systems Windows XP x64
Windows XP Professional x64 Edition
Microsoft Windows XP Professional x64 Edition released on April 25, 2005 is an edition of Windows XP for x86-64 personal computers. It is designed to use the expanded 64-bit memory address space provided by the x86-64 architecture....

, Windows Vista
Windows Vista
Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...

 x64, Windows 7 x64, Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

, BSD and Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

 that run 64-bit native, the software is also geared to fully utilize the capabilities of such processors. The move to 64 bits is more than just an increase in register size from the IA-32 as it also doubles the number of general-purpose registers.

The move to 64 bits by PowerPC
PowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...

 processors had been intended since the processors' design in the early 90s and was not a major cause of incompatibility. Existing integer registers are extended as are all related data pathways, but, as was the case with IA-32, both floating point and vector units had been operating at or above 64 bits for several years. Unlike what happened when IA-32 was extended to x86-64, no new general purpose registers were added in 64-bit PowerPC, so any performance gained when using the 64-bit mode for applications making no use of the larger address space is minimal.

Multicore designs

A different approach to improving a computer's performance is to add extra processors, as in symmetric multiprocessing
Symmetric multiprocessing
In computing, symmetric multiprocessing involves a multiprocessor computer hardware architecture where two or more identical processors are connected to a single shared main memory and are controlled by a single OS instance. Most common multiprocessor systems today use an SMP architecture...

 designs, which have been popular in servers and workstations since the early 1990s. Keeping up with Moore's Law
Moore's Law
Moore's law describes a long-term trend in the history of computing hardware: the number of transistors that can be placed inexpensively on an integrated circuit doubles approximately every two years....

 is becoming increasingly challenging as chip-making technologies approach their physical limits.

In response, microprocessor manufacturers look for other ways to improve performance in order to hold on to the momentum of constant upgrades in the market.

A multi-core processor is simply a single chip containing more than one microprocessor core. This effectively multiplies the processor's potential performance by the number of cores (as long as the operating system and software is designed to take advantage of more than one processor core). Some components, such as bus interface and second level cache, may be shared between cores. Because the cores are physically very close to each other, they can communicate with each other much faster than separate processors in a multiprocessor system, which improves overall system performance.

In 2005, the first personal computer dual-core processors were announced. As of 2009, dual-core and quad-core processors are widely used in servers, workstations and PCs while six and eight-core processors will be available for high-end applications in both the home and professional environments.

Sun Microsystems has released the Niagara
UltraSPARC T1
|right|262px|UltraSPARC T1 processorSun Microsystems' UltraSPARC T1 microprocessor, known until its 14 November 2005 announcement by its development codename "Niagara", is a multithreading, multicore CPU...

 and Niagara 2
UltraSPARC T2
Sun Microsystems' UltraSPARC T2 microprocessor is a multithreading, multi-core CPU. It is a member of the SPARC family, and the successor to the UltraSPARC T1. The chip is sometimes referred to by its codename, Niagara 2...

 chips, both of which feature an eight-core design. The Niagara 2 supports more threads and operates at 1.6 GHz.

High-end Intel Xeon processors that are on the LGA771 socket are DP (dual processor) capable, as well as the Intel Core 2 Extreme QX9775 also used in the Mac Pro by Apple and the Intel Skulltrail motherboard. With the transition to the LGA1366 and LGA1156 socket and the Intel i7 and i5 chips, quad core is now considered mainstream, but with the release of the i7-980x, six core processors are now well within reach.

RISC

In the mid-1980s to early-1990s, a crop of new high-performance Reduced Instruction Set Computer (RISC) microprocessors appeared, influenced by discrete RISC-like CPU designs such as the IBM 801
IBM 801
The 801 was an experimental minicomputer designed by IBM. The resulting architecture was used in various roles in IBM until the 1980s. The 801 was started as a pure research project led by John Cocke in October 1975 at the Thomas J. Watson Research Center. The name 801 comes from the building the...

 and others. RISC microprocessors were initially used in special-purpose machines and Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 workstation
Workstation
A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems...

s, but then gained wide acceptance in other roles.

In 1986, HP released its first system with a PA-RISC
PA-RISC
PA-RISC is an instruction set architecture developed by Hewlett-Packard. As the name implies, it is a reduced instruction set computer architecture, where the PA stands for Precision Architecture...

 CPU. The first commercial RISC microprocessor design was released either by MIPS Computer Systems, the 32-bit R2000
R2000 (microprocessor)
The R2000 is a microprocessor chip set developed by MIPS Computer Systems that implemented the MIPS I instruction set architecture . Introduced in January 1986, it was the first commercial implementation of the MIPS architecture and the first merchant RISC processor available to all companies...

 (the R1000 was not released) or by Acorn computers
Acorn Computers
Acorn Computers Ltd. was a British computer company established in Cambridge, England, in 1978. The company produced a number of computers which were especially popular in the UK. These included the Acorn Electron, the BBC Micro, and the Acorn Archimedes...

, the 32-bit ARM2
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...

 in 1987. The R3000 made the design truly practical, and the R4000
R4000
The R4000 is a microprocessor developed by MIPS Computer Systems that implemented the MIPS III instruction set architecture . Officially announced on 1 October 1991, it was one of the first 64-bit microprocessors and the first MIPS III implementation...

 introduced the world's first commercially available 64-bit RISC microprocessor. Competing projects would result in the IBM POWER
IBM POWER
POWER is a reduced instruction set computer instruction set architecture developed by IBM. The name is an acronym for Performance Optimization With Enhanced RISC....

 and Sun
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

 SPARC
SPARC
SPARC is a RISC instruction set architecture developed by Sun Microsystems and introduced in mid-1987....

 architectures. Soon every major vendor was releasing a RISC design, including the AT&T CRISP, AMD 29000, Intel i860
Intel i860
The Intel i860 was a RISC microprocessor from Intel, first released in 1989. The i860 was one of Intel's first attempts at an entirely new, high-end instruction set since the failed Intel i432 from the 1980s...

 and Intel i960
Intel i960
Intel's i960 was a RISC-based microprocessor design that became popular during the early 1990s as an embedded microcontroller, becoming a best-selling CPU in that field, along with the competing AMD 29000...

, Motorola 88000
Motorola 88000
The 88000 is a RISC instruction set architecture developed by Motorola. The 88000 was Motorola's attempt at a home-grown RISC architecture, started in the 1980s. The 88000 arrived on the market some two years after the competing SPARC and MIPS...

, DEC Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...

.

As of 2007, two 64-bit RISC architectures are still produced in volume for non-embedded applications: SPARC
SPARC
SPARC is a RISC instruction set architecture developed by Sun Microsystems and introduced in mid-1987....

 and Power ISA
Power Architecture
Power Architecture is a broad term to describe similar RISC instruction sets for microprocessors developed and manufactured by such companies as IBM, Freescale, AMCC, Tundra and P.A. Semi...

.

Special-purpose designs

A microprocessor is a general purpose system. Several specialized processing devices have followed from the technology. Microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...

s integrate a microprocessor with periphal devices for control of embedded system. A digital signal processor
Digital signal processor
A digital signal processor is a specialized microprocessor with an architecture optimized for the fast operational needs of digital signal processing.-Typical characteristics:...

 (DSP) is specialized for signal processing. Graphics processing unit
Graphics processing unit
A graphics processing unit or GPU is a specialized circuit designed to rapidly manipulate and alter memory in such a way so as to accelerate the building of images in a frame buffer intended for output to a display...

s may have no, limited, or general programming facilities. For example, GPUs through the 1990s were mostly non-programmable and have only recently gained limited facilities like programmable vertex shaders.

Market statistics

In 2003, about $44 billion (USD) worth of microprocessors were manufactured and sold. Although about half of that money was spent on CPUs used in desktop or laptop personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

s, those count for only about 2% of all CPUs sold.

About 55% of all CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

s sold in the world are 8-bit
8-bit
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 and the Motorola 6800 were also used in similar computers...

 microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...

s, over two billion of which were sold in 1997.

As of 2002, less than 10% of all the CPUs sold in the world are 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....

 or more. Of all the 32-bit CPUs sold, about 2% are used in desktop or laptop personal computers. Most microprocessors are used in embedded control applications such as household appliances, automobiles, and computer peripherals. Taken as a whole, the average price for a microprocessor, microcontroller, or DSP
Digital signal processor
A digital signal processor is a specialized microprocessor with an architecture optimized for the fast operational needs of digital signal processing.-Typical characteristics:...

 is just over $6.

About ten billion CPUs were manufactured in 2008. About 98% of new CPUs produced each year are embedded.

See also

  • Arithmetic logic unit
    Arithmetic logic unit
    In computing, an arithmetic logic unit is a digital circuit that performs arithmetic and logical operations.The ALU is a fundamental building block of the central processing unit of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers...

  • Central processing unit
    Central processing unit
    The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

  • CPU design
    CPU design
    CPU design is the design engineering task of creating a central processing unit , a component of computer hardware. It is a subfield of electronics engineering and computer engineering.- Overview :CPU design focuses on these areas:...

  • Comparison of CPU architectures
    Comparison of CPU architectures
    - Bits :Computer architectures are often described as n-bit architectures. Today n is often 8, 16, 32, or 64, but other sizes have been used. This is actually a strong simplification. A computer architecture often has a few more or less "natural" datasizes in the instruction set, but the hardware...

  • Computer architecture
    Computer architecture
    In computer science and engineering, computer architecture is the practical art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals and the formal modelling of those systems....

  • Computer engineering
    Computer engineering
    Computer engineering, also called computer systems engineering, is a discipline that integrates several fields of electrical engineering and computer science required to develop computer systems. Computer engineers usually have training in electronic engineering, software design, and...

  • Floating point unit
    Floating point unit
    A floating-point unit is a part of a computer system specially designed to carry out operations on floating point numbers. Typical operations are addition, subtraction, multiplication, division, and square root...

  • Instruction set
    Instruction set
    An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...

  • List of instruction sets
  • List of microprocessors
  • Microarchitecture
    Microarchitecture
    In computer engineering, microarchitecture , also called computer organization, is the way a given instruction set architecture is implemented on a processor. A given ISA may be implemented with different microarchitectures. Implementations might vary due to different goals of a given design or...

  • Microcode
    Microcode
    Microcode is a layer of hardware-level instructions and/or data structures involved in the implementation of higher level machine code instructions in many computers and other processors; it resides in special high-speed memory and translates machine instructions into sequences of detailed...

  • Microprocessor chronology
    Microprocessor Chronology
    -1970s:In the 1970s the microprocessors are mostly 8-bit and manufactured with the NMOS technology.-1980s:In the 1980s the microprocessors are 16-bit and 32-bit, mostly manufactured with the CMOS technology.-1990s:...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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