Central processing unit

CPUprocessorprocessorsCPUscomputer processorprocessor corecentral processing unitscentral processorcentral processor unitcomputer processors
A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that executes instructions that make up a computer program.wikipedia
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Computer data storage

main memorystoragememory
Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.
The central processing unit (CPU) of a computer is what manipulates data by performing computations.

Computer

computerscomputer systemdigital computer
A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that executes instructions that make up a computer program.
Conventionally, a modern computer consists of at least one processing element, typically a central processing unit (CPU) in the form of a metal-oxide-semiconductor (MOS) microprocessor, along with some type of computer memory, typically MOS semiconductor memory chips.

Processor register

registersregistergeneral purpose register
Principal components of a CPU include the arithmetic logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory) and execution of instructions by directing the coordinated operations of the ALU, registers and other components. Those operands may be specified as a constant value (called an immediate value), or as the location of a value that may be a processor register or a memory address, as determined by some addressing mode.
In computer architecture, a processor register is a quickly accessible location available to a computer's central processing unit (CPU).

Control unit

hardwiredhardwired controlHardwired control unit
Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.
The control unit (CU) is a component of a computer's central processing unit (CPU) that directs the operation of the processor.

Multi-core processor

dual-coremulti-corequad-core
Some computers employ a multi-core processor, which is a single chip containing two or more CPUs called "cores"; in that context, one can speak of such single chips as "sockets".
A multi-core processor is a computer processor integrated circuit with two or more separate processing units, called cores, each of which reads and executes program instructions, as if the computer had several processors.

System on a chip

SoCsystem-on-a-chipsystem-on-chip
An IC that contains a CPU may also contain memory, peripheral interfaces, and other components of a computer; such integrated devices are variously called microcontrollers or systems on a chip (SoC).
These components typically (but not always) include a central processing unit (CPU), memory, input/output ports and secondary storage – all on a single substrate or microchip, the size of a coin.

Microcontroller

microcontrollersMCUmicro-controller
An IC that contains a CPU may also contain memory, peripheral interfaces, and other components of a computer; such integrated devices are variously called microcontrollers or systems on a chip (SoC).
A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals.

CPU socket

socketsocketsprocessor socket
Some computers employ a multi-core processor, which is a single chip containing two or more CPUs called "cores"; in that context, one can speak of such single chips as "sockets".
This allows for placing and replacing the central processing unit (CPU) without soldering.

Vector processor

vector processingvectorarray processor
Array processors or vector processors have multiple processors that operate in parallel, with no unit considered central. Additionally while discrete transistor and IC CPUs were in heavy usage, new high-performance designs like SIMD (Single Instruction Multiple Data) vector processors began to appear.
In computing, a vector processor or array processor is a central processing unit (CPU) that implements an instruction set containing instructions that operate on one-dimensional arrays of data called vectors, compared to the scalar processors, whose instructions operate on single data items.

Processor (computing)

processorprocessorscomputer processor
Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.
The term is frequently used to refer to the central processor (central processing unit) in a system, but typical computer systems (especially SoCs) combine a number of specialised "processors".

Software

Computer softwareSoftware & Programmingsoftware technology
Since the term "CPU" is generally defined as a device for software (computer program) execution, the earliest devices that could rightly be called CPUs came with the advent of the stored-program computer.
At the lowest programming level, executable code consists of machine language instructions supported by an individual processor—typically a central processing unit (CPU) or a graphics processing unit (GPU).

Mainframe computer

mainframemainframesmainframe computers
This standardization began in the era of discrete transistor mainframes and minicomputers and has rapidly accelerated with the popularization of the integrated circuit (IC).
The term originally referred to the large cabinets called "main frames" that housed the central processing unit and main memory of early computers.

Minicomputer

minicomputersmini-computermini
This standardization began in the era of discrete transistor mainframes and minicomputers and has rapidly accelerated with the popularization of the integrated circuit (IC).
When single-chip CPU microprocessors appeared, beginning with the Intel 4004 in 1971, the term "minicomputer" came to mean a machine that lies in the middle range of the computing spectrum, in between the smallest mainframe computers and the microcomputers.

Microprocessor

microprocessorsprocessorprocessors
Most modern CPUs are microprocessors, where the CPU is contained on a single metal-oxide-semiconductor (MOS) integrated circuit (IC) chip.
The application of MOS LSI chips to computing was the basis for the first microprocessors, as engineers began recognizing that a complete computer processor could be contained on several MOS LSI chips.

Microcode

microprogrammicroprogrammingmicroprogrammed
To facilitate this improvement, IBM used the concept of a microprogram (often called "microcode"), which still sees widespread usage in modern CPUs.
Microcode is used in general-purpose central processing units, although in current desktop CPUs it is only a fallback path for cases that the faster hardwired control unit cannot handle.

Von Neumann architecture

von Neumannvon Neumann bottleneckvon Neumann machine
While von Neumann is most often credited with the design of the stored-program computer because of his design of EDVAC, and the design became known as the von Neumann architecture, others before him, such as Konrad Zuse, had suggested and implemented similar ideas.
The shared bus between the program memory and data memory leads to the von Neumann bottleneck, the limited throughput (data transfer rate) between the central processing unit (CPU) and memory compared to the amount of memory.

SIMD

single instruction, multiple dataSingle Instruction Multiple DataSIMD lanes
Additionally while discrete transistor and IC CPUs were in heavy usage, new high-performance designs like SIMD (Single Instruction Multiple Data) vector processors began to appear.
Most modern CPU designs include SIMD instructions to improve the performance of multimedia use.

Supercomputer

high-performance computinghigh performance computingsupercomputing
These early experimental designs later gave rise to the era of specialized supercomputers like those made by Cray Inc and Fujitsu Ltd.
Through the 1960s, they began to add increasing amounts of parallelism with one to four processors being typical.

Input/output

I/Ooutputinterface
Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions.
In computer architecture, the combination of the CPU and main memory, to which the CPU can read or write directly using individual instructions, is considered the brain of a computer.

Harvard architecture

HarvardHarvard computer architectureHarvard memory architecture
The so-called Harvard architecture of the Harvard Mark I, which was completed before EDVAC, also used a stored-program design using punched paper tape rather than electronic memory.
These early machines had data storage entirely contained within the central processing unit, and provided no access to the instruction storage as data.

Intel 4004

4004MCS-4first commercially available microprocessor (Intel 4004)
Since the introduction of the first commercially available microprocessor, the Intel 4004 in 1971, and the first widely used microprocessor, the Intel 8080 in 1974, this class of CPUs has almost completely overtaken all other central processing unit implementation methods.
The Intel 4004(pronounced:forty-oh-four or four-thousand-four) is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971.

Instruction set architecture

instruction setinstructionsinstruction
A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that executes instructions that make up a computer program.
A realization of an ISA, such as a central processing unit (CPU), is called an implementation.

Computer program

programprogramscomputer programs
A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that executes instructions that make up a computer program.
Object code needs further processing to become machine code, and machine code consists of the central processing unit's native instructions, ready for execution.

PDP-11

LSI-11PDP-11/70DEC PDP-11
DEC's PDP-8/I and KI10 PDP-10 also switched from the individual transistors used by the PDP-8 and PDP-10 to SSI ICs, and their extremely popular PDP-11 line was originally built with SSI ICs but was eventually implemented with LSI components once these became practical.
Instead, memory was interfaced by dedicated circuitry and space in the CPU cabinet, while the Unibus continued to be used for I/O only.

Addressing mode

indirect addressingconditional executionindirect address
Those operands may be specified as a constant value (called an immediate value), or as the location of a value that may be a processor register or a memory address, as determined by some addressing mode.
Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs.