Difference between revisions of "CPU"

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== CPU ==
 
== CPU ==
  
The '''[[CPU|CPU]]''' (an acronym for '''Central Processing Unit''') is the primary [[Electronic circuit|electronic circuitry]] within a computer that executes instructions of computer programs. It is often referred to as the "brain" of the computer because it performs most of the processing and calculations.
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The '''CPU''' (Central Processing Unit) is the main electronic part of a computer that executes program instructions. Often called the computer's "brain," it handles most processing and calculations.
  
The [[CPU|CPU]]'s main job is to repeatedly fetch, decode, and execute instructions. These instructions tell the computer what to do, performing tasks like arithmetic operations (addition, subtraction), logic operations (comparing values), controlling the flow of information, and managing other components.
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The CPU's primary job is to constantly fetch, decode, and execute instructions. These instructions tell the computer what to do, from performing math (like addition or subtraction) and logic operations (comparing values) to managing information flow and controlling other components.
  
 
=== Key Components ===
 
=== Key Components ===
  
A [[CPU|CPU]] is made up of several key components working together:
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A CPU contains several interconnected parts:
 
 
* '''Arithmetic Logic Unit (ALU):''' This part performs all the arithmetic and logic operations.
 
* '''Control Unit:''' This unit manages the execution of instructions. It fetches instructions from memory, decodes them to figure out what they mean, and directs the other parts of the [[CPU|CPU]] and computer system to perform the necessary operations.
 
* '''Registers:''' These are small, fast storage locations within the [[CPU|CPU]] used to hold data and instructions that the [[CPU|CPU]] is currently working on.
 
  
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'''Arithmetic Logic Unit (ALU):''' Performs all arithmetic and logic operations.
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'''Control Unit:''' Manages instruction execution. It gets instructions from memory, decodes them, and directs the CPU and other computer parts to perform tasks.
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'''Registers:''' Small, very fast storage areas within the CPU that hold data and instructions the CPU is actively using.
 
=== How it Works (Basic Cycle) ===
 
=== How it Works (Basic Cycle) ===
  
The [[CPU|CPU]] operates on a cycle for each instruction:
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The CPU processes each instruction in a continuous cycle:
  
1.  **Fetch:** The Control Unit gets the next instruction from the computer's main memory, typically [[RAM]].
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Fetch: The Control Unit retrieves the next instruction from the computer's main memory (typically RAM).
2.  **Decode:** The Control Unit translates the instruction into commands that the [[CPU|CPU]]'s other parts can understand.
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Decode: The Control Unit translates the instruction into commands the CPU's other parts can understand.
3.  **Execute:** The [[CPU|CPU]] performs the operation specified by the instruction, such as using the ALU to perform a calculation or moving data between registers or memory.
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Execute: The CPU performs the operation specified by the instruction, such as a calculation using the ALU or moving data.
 
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This cycle repeats millions or billions of times per second, depending on the CPU's speed.
This cycle repeats millions or billions of times per second, depending on the [[CPU|CPU]]'s speed.
 
  
 
=== Characteristics Affecting Performance ===
 
=== Characteristics Affecting Performance ===
  
Several factors determine how powerful or fast a [[CPU|CPU]] is:
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Several factors determine a CPU's power and speed:
 
 
* '''Clock Speed:''' Measured in gigahertz (GHz), this indicates how many cycles the [[CPU|CPU]] can perform per second. A higher clock speed generally means faster instruction execution.
 
* '''Number of Cores:''' Modern [[CPU|CPU]]s often have multiple "cores," which are essentially multiple processing units on a single chip. More cores allow the [[CPU|CPU]] to execute multiple instructions or programs simultaneously.
 
* '''Cache Size:''' [[Cache memory]] is a small, very fast memory located within or near the [[CPU|CPU]] that stores frequently used data and instructions. A larger and faster cache can reduce the time the [[CPU|CPU]] spends waiting for data from the slower main memory ([[RAM]]).
 
* '''Instruction Set Architecture (ISA):''' This is the set of commands that a specific [[CPU|CPU]] can understand and execute. Different architectures (like x86-64 or ARM) have different ISAs, affecting efficiency and compatibility with [[Software|software]].
 
  
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'''Clock Speed:''' Measured in gigahertz (GHz), this indicates how many cycles the CPU can perform per second. Higher clock speed generally means faster instruction execution.
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'''Number of Cores:''' Modern CPUs have multiple "cores," which are essentially separate processing units on one chip. More cores allow the CPU to handle multiple instructions or programs simultaneously.
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'''Cache Size:''' Cache memory is a small, very fast memory within or near the CPU. It stores frequently used data and instructions, reducing how long the CPU waits for data from slower main memory (RAM).
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'''Instruction Set Architecture (ISA):''' This is the specific set of commands a CPU understands. Different architectures (like x86-64 or ARM) have different ISAs, affecting efficiency and software compatibility.
 
=== Evolution ===
 
=== Evolution ===
  
[[CPU|CPU]]s have evolved dramatically since the first processors. Early [[CPU|CPU]]s were large, complex chips with a single core. Over time, technology has allowed manufacturers to integrate more transistors, leading to smaller, faster, and more powerful designs. A major shift was the move from single-core to multi-core processors, enabling parallel processing and improving performance for demanding tasks and multitasking.
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CPUs have changed dramatically. Early CPUs were large, complex, single-core chips. Over time, technology allowed integrating more transistors, leading to smaller, faster, and more powerful designs. A significant leap was the move to multi-core processors, enabling parallel processing and boosting performance for demanding tasks and multitasking.
  
The [[CPU|CPU]] is installed on the [[Motherboard]], and its performance is heavily reliant on other system components, particularly the speed and amount of [[RAM]] which provides the data and instructions the [[CPU|CPU]] needs to process.
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The CPU is installed on the motherboard, and its performance depends heavily on other system components, especially the speed and amount of RAM, which feeds the CPU the data and instructions it needs.
  
 
=== See Also ===
 
=== See Also ===
  
* [[Motherboard]]
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*[[Motherboard]]
* [[RAM]]
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*[[RAM]]
* [[Instruction set architecture]]
 
 
 
=== References ===
 
 
 
* {{cite book |last=Stallings |first=William |title=Computer Organization and Architecture: Designing for Performance |publisher=Pearson |year=2019 |edition=11th |isbn=978-0134997183}} - A standard textbook covering CPU architecture.
 
* {{cite book |last=Patterson |first=David A. |last2=Hennessy |first2=John L. |title=Computer Organization and Design RISC-V Edition: The Hardware/Software Interface |publisher=Morgan Kaufmann |year=2017 |isbn=978-0128122754}} - Another widely used textbook on computer architecture.
 
* [https://www.intel.com/content/www/us/en/processors/central-processing-unit.html Intel - What is a CPU?] - Explanation from a major CPU manufacturer.
 
* [https://www.amd.com/en/topics/cpu.html AMD - What is a CPU?] - Explanation from another major CPU manufacturer.
 
* [https://www.britannica.com/technology/central-processing-unit Britannica - Central Processing Unit] - Encyclopedia article on CPUs.
 
  
 
[[Category:CPUs]]
 
[[Category:CPUs]]
[[Category:Computer hardware]]
 
[[Category:Computer architecture]]
 
[[Category:Electronic components]]
 

Latest revision as of 13:51, 27 May 2025

CPU

The CPU (Central Processing Unit) is the main electronic part of a computer that executes program instructions. Often called the computer's "brain," it handles most processing and calculations.

The CPU's primary job is to constantly fetch, decode, and execute instructions. These instructions tell the computer what to do, from performing math (like addition or subtraction) and logic operations (comparing values) to managing information flow and controlling other components.

Key Components

A CPU contains several interconnected parts:

Arithmetic Logic Unit (ALU): Performs all arithmetic and logic operations. Control Unit: Manages instruction execution. It gets instructions from memory, decodes them, and directs the CPU and other computer parts to perform tasks. Registers: Small, very fast storage areas within the CPU that hold data and instructions the CPU is actively using.

How it Works (Basic Cycle)

The CPU processes each instruction in a continuous cycle:

Fetch: The Control Unit retrieves the next instruction from the computer's main memory (typically RAM). Decode: The Control Unit translates the instruction into commands the CPU's other parts can understand. Execute: The CPU performs the operation specified by the instruction, such as a calculation using the ALU or moving data. This cycle repeats millions or billions of times per second, depending on the CPU's speed.

Characteristics Affecting Performance

Several factors determine a CPU's power and speed:

Clock Speed: Measured in gigahertz (GHz), this indicates how many cycles the CPU can perform per second. Higher clock speed generally means faster instruction execution. Number of Cores: Modern CPUs have multiple "cores," which are essentially separate processing units on one chip. More cores allow the CPU to handle multiple instructions or programs simultaneously. Cache Size: Cache memory is a small, very fast memory within or near the CPU. It stores frequently used data and instructions, reducing how long the CPU waits for data from slower main memory (RAM). Instruction Set Architecture (ISA): This is the specific set of commands a CPU understands. Different architectures (like x86-64 or ARM) have different ISAs, affecting efficiency and software compatibility.

Evolution

CPUs have changed dramatically. Early CPUs were large, complex, single-core chips. Over time, technology allowed integrating more transistors, leading to smaller, faster, and more powerful designs. A significant leap was the move to multi-core processors, enabling parallel processing and boosting performance for demanding tasks and multitasking.

The CPU is installed on the motherboard, and its performance depends heavily on other system components, especially the speed and amount of RAM, which feeds the CPU the data and instructions it needs.

See Also