How Computer works?

16 mins read

A computer is a marvel of engineering, composed of various components that work harmoniously to execute tasks. These components, including the input, the computing unit, and the output, collaborate seamlessly to deliver the incredible computing power we rely on in our daily lives. Let’s delve deeper into each element, exploring their historical context, modern-day relevance, and the fascinating workflow they facilitate.

At the core of computer operations lies the concept of input, processing, and output. This fundamental workflow defines how computers handle tasks and deliver results. When you interact with a computer, such as pressing a key on the keyboard, the action serves as input. The computer’s processing unit, typically the CPU, receives the input and performs the necessary calculations and operations. Finally, the processed information is presented as output, often visible on the screen or conveyed through other output devices such as speakers or printers.

Input Devices: Initiating the Interaction

Input devices act as the bridge between users and computers, enabling us to provide instructions and data to these electronic marvels. Keyboards, mice, touchscreens, voice recognition systems, and even virtual reality interfaces all serve as input devices. These devices have evolved significantly over time, reflecting our ever-growing desire for more intuitive and efficient interactions with computers.

Historically, input devices like punch cards and paper tape readers were common during the early days of computing. However, as technology advanced, devices like the QWERTY keyboard, invented in the late 19th century, gained popularity and became a standard input method for personal computers. Today, touchscreens and voice recognition technologies have further transformed the way we interact with computers, making the input process more natural and intuitive.

In the ever-evolving world of technology, input devices play a crucial role in bridging the gap between humans and computers. These devices allow us to interact with digital systems, providing commands, data, and instructions that enable the computer to perform a wide range of tasks. From the humble keyboard to cutting-edge touchscreens, let’s explore the fascinating world of input devices, their history, functionalities, and the diverse ways they enhance our computing experience.

Keyboard: The Language of Computers


The keyboard, a ubiquitous input device, has been an integral part of computers since their inception. Its origins can be traced back to the early typewriters, which laid the foundation for the modern computer keyboard. With a layout inspired by the QWERTY system, keyboards provide a familiar interface for users to input alphanumeric characters, commands, and shortcuts. Over the years, keyboards have evolved to include additional functionalities such as multimedia keys, programmable keys, and ergonomic designs, catering to the diverse needs of users across different domains.

Mouse: Point, Click, Interact


The mouse, introduced with the advent of graphical user interfaces, revolutionized the way we interact with computers. Its ability to move a cursor on the screen and provide precise input has become a standard feature in modern computing. From the traditional mechanical mouse to the optical and wireless variants, the mouse offers a convenient and intuitive means of navigating graphical interfaces, selecting items, and performing various operations. With the addition of scroll wheels, extra buttons, and advanced sensors, mice have become indispensable tools for both casual users and professionals in design, gaming, and other fields.

Touchscreens: Direct Interaction at Your Fingertips


The rise of touchscreens has brought a new dimension to input devices, allowing users to interact directly with digital content using their fingers or styluses. Initially popularized by smartphones and tablets, touchscreens have expanded into laptops, all-in-one computers, and even interactive displays. Capacitive touchscreens, which rely on the electrical properties of human touch, enable gestures such as tapping, swiping, pinching, and zooming, providing an intuitive and immersive user experience. Multi-touch capabilities and pressure sensitivity further enhance the versatility of touchscreens, enabling complex interactions and precise input in creative applications.

Voice Recognition: Speak and Command

Voice recognition

Advancements in voice recognition technology have paved the way for voice input as an alternative to traditional input devices. Voice assistants like Siri, Alexa, and Google Assistant have become household names, allowing users to interact with computers and devices through natural language commands. From dictating text to controlling smart home devices, voice recognition offers convenience and hands-free operation. As machine learning and artificial intelligence continue to advance, voice recognition is poised to play an even more significant role in our daily interactions with technology.

Other Input Devices: Beyond the Basics

Beyond the keyboard, mouse, and touchscreens, a vast array of specialized input devices cater to specific needs and applications. These include:

  1. Graphics Tablets: Widely used by artists, designers, and illustrators, graphics tablets provide a digital canvas for precise pen input and drawing capabilities.
  2. Game Controllers: Designed for gaming enthusiasts, game controllers offer a range of input options, including buttons, triggers, joysticks, and motion sensors, enabling immersive gameplay experiences.
  3. Trackpads: Found in laptops and certain input devices, trackpads provide an alternative to the traditional mouse, allowing users to navigate and interact through finger movements on a touch-sensitive surface.
  4. Scanners: Scanners convert physical documents, images, or objects into digital formats, enabling easy storage, editing, and sharing.
  5. Biometric Input Devices: Biometric devices, such as fingerprint scanners and facial recognition cameras, provide secure and personalized authentication for devices, systems, and applications.

The Future of Input Devices: Innovations and Beyond

As technology continues to advance, input devices are poised to undergo further transformations. Emerging technologies, such as gesture recognition, haptic feedback, brain-computer interfaces, and eye-tracking systems, hold immense potential to reshape the way we interact with computers. These innovations have the power to enhance accessibility, improve user experiences, and unlock new possibilities in fields ranging from gaming and virtual reality to healthcare and productivity.

In conclusion, input devices serve as the gateway between humans and computers, facilitating seamless communication and interaction. From the traditional keyboard and mouse to the latest touchscreens and voice recognition systems, these devices continue to evolve, offering intuitive, efficient, and immersive ways to input commands, data, and instructions into the digital realm. As technology advances and new possibilities emerge, the future of input devices holds exciting prospects, promising to enhance our computing experiences and push the boundaries of human-computer interaction.

Central Processing Unit (CPU): The Engine of Computation

At the heart of every computer lies a powerful and essential component known as the Central Processing Unit (CPU). Often referred to as the brain of the computer, the CPU is responsible for executing instructions, performing calculations, and managing the overall operation of the system. Let’s delve into the fascinating world of CPUs, exploring their functions, architecture, performance, and the pivotal role they play in enabling our digital experiences.


The Central Processing Unit (CPU) is often referred to as the “brain” of the computer. It consists of multiple units working in unison to process instructions and perform calculations swiftly and accurately. The CPU’s historical evolution is a testament to the extraordinary progress made in computer architecture and chip design.

The concept of the CPU can be traced back to the work of mathematician and logician Charles Babbage in the early 19th century. However, it wasn’t until the mid-20th century that the first practical CPUs, such as the Electronic Numerical Integrator and Computer (ENIAC), were developed. Today, CPUs incorporate microprocessors, which contain millions, and even billions, of transistors on a single chip.

Functions of the CPU: Processing Power Unleashed

The CPU serves as the powerhouse of the computer, carrying out a multitude of tasks to ensure smooth operation. Some of the primary functions of the CPU include:

  1. Instruction Execution: The CPU executes instructions stored in memory, fetching them, decoding their meaning, and performing the necessary operations.
  2. Arithmetic and Logic Operations: The Arithmetic Logic Unit (ALU) within the CPU handles mathematical calculations, logical operations, and data manipulation tasks.
  3. Control and Coordination: The Control Unit (CU) of the CPU manages the flow of instructions, coordinates data transfer between different components, and ensures proper synchronization of operations.
  4. Memory Management: The CPU interacts with the memory subsystem, accessing data and instructions stored in primary and secondary memory.

CPU Architecture: From Cores to Clock Speeds

CPU architecture refers to the design and organization of the CPU’s internal components. Key elements of CPU architecture include:

  1. Cores: Modern CPUs often consist of multiple cores, each capable of executing instructions independently. These cores allow for parallel processing, enhancing overall performance and multitasking capabilities.
  2. Clock Speed: The clock speed, measured in gigahertz (GHz), determines the number of instructions a CPU can execute per second. Higher clock speeds generally result in faster processing.
  3. Cache Memory: CPUs feature different levels of cache memory, including L1, L2, and L3 caches, which provide quick access to frequently used data, reducing the need to fetch information from slower main memory.
  4. Instruction Set Architecture (ISA): The ISA defines the set of instructions a CPU can understand and execute. Common ISAs include x86, ARM, and RISC-V, each with its own characteristics and supported software.

Performance Factors: Power and Efficiency

CPU performance depends on various factors, including:

  1. Clock Speed and Instructions per Cycle (IPC): Higher clock speeds and improved IPC allow CPUs to execute more instructions within a given time frame, resulting in increased performance.
  2. Core Count and Multithreading: CPUs with more cores can handle multiple tasks simultaneously, ideal for multitasking, content creation, and demanding applications that benefit from parallel processing.
  3. Thermal Design Power (TDP): TDP refers to the maximum amount of heat generated by a CPU under normal operating conditions. Lower TDP values indicate greater power efficiency and reduced heat output.
  4. Advanced Technologies: CPUs incorporate advanced features like branch prediction, pipelining, and advanced vector extensions (AVX) to enhance performance, efficiency, and overall computational capabilities.

Evolution and Future Trends: Pushing the Boundaries

The history of CPUs is marked by continuous advancements and innovations. From the early days of simple microprocessors to the era of complex multicore architectures, CPUs have witnessed remarkable progress. Historical milestones include the development of the first microprocessor, the Intel 4004, in 1971, and the introduction of superscalar and out-of-order execution techniques in later generations.

Looking ahead, the future of CPUs is filled with exciting possibilities. As technology advances, we can expect:

  1. More Cores: CPUs with higher core counts and improved multithreading capabilities will enable even greater parallel processing and enhanced multitasking performance.
  2. Increased Efficiency: Ongoing research focuses on improving power efficiency and reducing energy consumption, leading to more environmentally friendly and energy-efficient CPUs.
  3. Specialized Processors: With the rise of artificial intelligence (AI), machine learning (ML), and data-intensive applications, specialized processors like graphics processing units (GPUs) and neural processing units (NPUs) are gaining prominence alongside traditional CPUs.
  4. Quantum Computing: Quantum processors, utilizing the principles of quantum mechanics, hold the potential to revolutionize computing, solving complex problems at an unprecedented scale.

In conclusion, the CPU stands as the fundamental component that drives the computing power and capabilities of modern computers. Its ability to execute instructions, perform complex calculations, and manage system operations ensures the smooth functioning of our digital experiences. As CPUs continue to evolve, embracing higher core counts, improved efficiency, and cutting-edge technologies, they will shape the future of computing, unlocking new frontiers and empowering us to tackle increasingly complex challenges.

The Control Unit: Orchestrating the Computer’s Operations

Within the Central Processing Unit (CPU), the Control Unit (CU) plays a crucial role in managing and coordinating the various operations of the computer. Serving as the brain’s conductor, the Control Unit ensures that instructions are executed in the correct sequence and that data is properly processed and transferred. Let’s explore the functions and significance of the Control Unit in more detail.

Instruction Decoding and Control: Interpreting Commands

One of the primary tasks of the Control Unit is to decode instructions fetched from memory and determine the appropriate actions to be taken. It analyzes the instruction’s opcode (operation code) to identify the specific operation the computer needs to perform. By decoding instructions, the Control Unit ensures that the CPU knows how to execute each command effectively.

Instruction Sequencing: Orchestrating Operations

The Control Unit is responsible for maintaining the proper sequencing of instructions and operations within the CPU. It ensures that instructions are executed in the correct order, following the program’s logical flow. By orchestrating the execution of instructions, the Control Unit enables the CPU to perform tasks accurately and efficiently.

Execution Control: Coordinating Operations

In addition to sequencing instructions, the Control Unit coordinates the execution of various operations within the CPU. It interacts with different components, such as the Arithmetic Logic Unit (ALU) and memory subsystem, to ensure that data is properly processed, transferred, and stored.

Timing and Synchronization: Managing Clock Cycles

The Control Unit plays a crucial role in managing timing and synchronization within the CPU. It synchronizes the execution of instructions and operations, ensuring that each component performs its tasks in harmony with the system clock. By coordinating the timing of operations, the Control Unit maximizes the CPU’s efficiency and ensures the integrity of data processing.

The Arithmetic Logic Unit (ALU): Number Crunching and Logical Operations

Working in tandem with the Control Unit, the Arithmetic Logic Unit (ALU) forms the computational powerhouse of the CPU. The ALU is responsible for performing arithmetic calculations, logical operations, and data manipulation tasks. Let’s explore the key functions and significance of the ALU in more detail.

Arithmetic Operations: Crunching Numbers

The ALU handles various arithmetic operations, including addition, subtraction, multiplication, and division. It performs calculations on binary numbers, manipulating the binary representations of data to yield the desired results. By executing these arithmetic operations, the ALU enables the CPU to perform mathematical computations necessary for a wide range of applications.

Logical Operations: Evaluating Conditions

In addition to arithmetic calculations, the ALU performs logical operations, such as AND, OR, and NOT. These operations are essential for evaluating conditions and making decisions within computer programs. The ALU compares binary values, applying logical rules to determine the outcome of logical expressions or conditions.

Data Manipulation: Shifting and Bitwise Operations

The ALU also handles data manipulation tasks, such as shifting and bitwise operations. Shifting involves moving binary digits to the left or right, effectively multiplying or dividing by powers of two. Bitwise operations manipulate individual bits of binary numbers, performing operations like AND, OR, XOR, and complementing bits. These operations are useful for tasks such as data encryption, data compression, and bitwise calculations.

Register Operations: Temporary Storage

The ALU interacts closely with CPU registers, temporary storage locations within the CPU. It retrieves data from registers, performs calculations, and stores the results back into registers for further processing. The ALU’s interaction with registers enables efficient data manipulation and facilitates the flow of information within the CPU.

As we see, the Control Unit and Arithmetic Logic Unit form the backbone of the CPU, working in harmony to execute instructions, perform calculations, and manage the overall operation of the computer. While the Control Unit ensures the correct sequencing and coordination of operations, the ALU handles arithmetic calculations, logical operations, and data manipulation tasks. Together, these components drive the CPU’s computational power and enable the computer to perform a vast array of tasks, from simple arithmetic operations to complex data processing and decision-making.

Memory Units: Storing and Retrieving Data

Memory units within a computer play a vital role in storing and retrieving data quickly and efficiently. Two primary types of memory are typically present in computers: main memory (also known as RAM) and auxiliary memory.


Main Memory (RAM): Random Access Memory (RAM) provides temporary storage for data and instructions that the CPU actively uses during program execution. RAM allows for fast access to data, significantly enhancing the computer’s performance. The capacity and speed of RAM have witnessed remarkable advancements over time, enabling computers to handle increasingly complex tasks.

Auxiliary Memory: Auxiliary memory, commonly referred to as secondary storage or storage devices, retains data even when the computer is powered off. Hard disk drives (HDDs), solid-state drives (SSDs), and optical drives (e.g., CD/DVD) are examples of auxiliary memory devices. They offer larger storage capacities but at slower access speeds compared to main memory. The evolution of auxiliary memory has seen the rise of technologies such as solid-state drives, which provide faster access times and enhanced reliability.

A separate article on memory units with more details is available here.

Output Devices: Enhancing the Computer Experience

In the world of computers, input devices allow us to interact and provide instructions, but it is the output devices that bring the results of our interactions to life. These devices enable us to see, hear, and perceive the output produced by the computer, making our computing experiences more immersive and engaging. Let’s dive deeper into the realm of output devices and explore their functionalities, historical evolution, and their impact on modern-day computing.

Display Devices: Visualizing the Output

Display devices play a crucial role in visualizing the output generated by computers.


Over the years, they have undergone significant advancements in technology and design, offering stunning visual experiences. Here are some key display devices and their usability:

  1. Monitors: Monitors have come a long way since the early days of computing. From the bulky CRT (cathode ray tube) monitors to the sleek and slim LCD (liquid crystal display) and LED (light-emitting diode) monitors of today, they have transformed the way we interact with visual content. With higher resolutions, wider color gamuts, and faster refresh rates, modern monitors deliver crisp and vibrant images, making them essential for tasks ranging from basic computing to graphic design and multimedia creation.
  2. Projectors: Projectors have revolutionized the way we share content on a larger scale. Whether it’s for presentations in classrooms, boardrooms, or home theaters, projectors enable us to project computer output onto screens or surfaces, creating immersive visual experiences for a broader audience. Advancements in projection technology have resulted in higher resolutions, improved brightness, and enhanced connectivity options, making projectors versatile tools for sharing multimedia content in various settings.
  3. Televisions: Televisions have evolved from being simple broadcast receivers to becoming sophisticated display devices for computers and other multimedia sources. With the rise of smart TVs, users can seamlessly connect their computers to the television and enjoy a larger display for gaming, video streaming, and other multimedia applications. Modern televisions boast features like 4K resolution, HDR (high dynamic range) support, and smart functionalities, providing users with an immersive visual experience right from their living rooms.

Audio Devices: Amplifying Sound

Audio devices enrich our computing experiences by delivering high-quality sound output.


They allow us to enjoy music, movies, and other multimedia content with enhanced clarity and immersion. Let’s explore some noteworthy audio devices and their usability:

  1. Speakers: Speakers have undergone tremendous advancements, from basic mono speakers to sophisticated surround sound systems and portable Bluetooth speakers. They enable us to hear sound output from our computers, immersing us in music, movie soundtracks, and virtual environments. Modern speakers incorporate advanced technologies like Dolby Atmos, which creates a three-dimensional audio experience, and wireless connectivity options that offer convenience and flexibility.
  2. Headphones and Earphones: Personal audio devices, such as headphones and earphones, provide a more private and immersive audio experience. They allow us to enjoy sound output without disturbing others and are widely used for listening to music, watching movies, gaming, and communication. From wired to wireless, open-back to noise-canceling, headphones and earphones come in various designs to cater to different preferences and needs.
  3. Soundbars: Soundbars have gained popularity as an audio enhancement solution for televisions and computers. These sleek and compact speaker systems offer improved audio quality, especially for thin televisions that may have limited built-in speakers. Soundbars provide a wider soundstage and better clarity, enhancing the overall audio experience when watching movies, playing games, or listening to music.

Printers: Transforming Digital to Physical

Printers play a vital role in converting digital output into tangible, physical form.


They allow us to create hard copies of documents, images, and other materials. Let’s explore some common types of printers and their usability:

  1. Inkjet Printers: Inkjet printers are versatile and widely used for both home and office environments. They utilize inkjet technology to propel tiny droplets of ink onto paper, resulting in high-quality prints. Inkjet printers are capable of producing vivid colors and sharp text, making them suitable for a wide range of applications, including document printing, photo printing, and graphic design.
  2. Laser Printers: Laser printers have become a staple in office environments where fast and efficient printing of text documents is required. They use laser technology to produce high-resolution prints with precise details. Laser printers are known for their speedy performance, cost-effective printing, and durability, making them ideal for businesses and professionals who need high-volume, high-quality printing.
  3. 3D Printers: 3D printers have revolutionized the way we think about output devices. These remarkable devices can create three-dimensional objects by gradually adding layers of material, such as plastic or resin, based on digital models. 3D printing has found applications in fields like prototyping, product design, medical advancements, and even aerospace engineering. With the ability to transform virtual designs into physical objects, 3D printers have opened up endless possibilities for innovation and creativity. A separate post on 3D-Printing is available here.

Other Output Devices: Expanding Possibilities

While display devices, speakers, and printers are the primary output devices, there are other specialized devices that cater to specific needs and enable unique interactions. Let’s explore a few notable examples:

  1. Haptic Devices: Haptic devices provide tactile feedback, allowing users to feel virtual objects or sensations. They are commonly used in gaming, virtual reality (VR), and simulation applications. Devices like force-feedback joysticks and haptic gloves enable users to experience physical feedback, enhancing the immersion and realism of virtual environments.
  2. Braille Displays: Braille displays cater to individuals with visual impairments, providing a means to convert digital text into Braille characters. These displays use small physical pins that rise and fall to create Braille characters, enabling visually impaired users to read and navigate through digital content independently. Braille displays have played a significant role in making computers and digital information more accessible and inclusive.
  3. LED Indicators: LED indicators are small lights found on various devices, serving as visual indicators for status, connectivity, or activity. They are commonly seen on keyboards, mice, routers, and other devices, providing users with valuable feedback and information at a glance. LED indicators help users monitor device functionality, network connections, and other important aspects of their computing experience.

In conclusion, output devices are essential components of any computer system, enabling us to perceive and utilize the output generated by computers. Display devices visualize output in stunning detail, audio devices enrich our experiences with immersive sound, and printers transform digital content into physical form. Specialized output devices cater to unique needs, expanding the possibilities of human-computer interactions. With advancements in technology, these devices continue to evolve, offering increasingly immersive experiences and empowering us to engage with digital content in new and exciting ways. As technology progresses, output devices will undoubtedly play a crucial role in shaping the future of computing and human-computer interactions.

Modern Advancements: From Multicore Processors to Specialized Units

In recent years, computers have witnessed remarkable advancements, transforming their capabilities and performance. Here are some notable developments:

  1. Multicore Processors: To enhance processing power and efficiency, modern CPUs often integrate multiple processor cores into a single chip. This allows computers to execute multiple tasks simultaneously, resulting in improved multitasking capabilities and faster processing speeds.
  2. Graphics Processing Units (GPUs): Originally designed for rendering graphics, GPUs have evolved into powerful parallel processors. They excel at handling highly parallelizable tasks, making them ideal for applications like 3D rendering, artificial intelligence, and cryptocurrency mining.
  3. Specialized Processing Units: With the rise of artificial intelligence and machine learning, specialized units like Tensor Processing Units (TPUs) and Field-Programmable Gate Arrays (FPGAs) have emerged. These units offer optimized performance for specific computational tasks, enabling efficient processing of large datasets and complex algorithms.
  4. Quantum Computing: At the cutting edge of computer technology, quantum computing explores the principles of quantum mechanics to enable groundbreaking computational power. Quantum computers utilize quantum bits, or qubits, to perform computations that conventional computers cannot efficiently solve. Although still in its early stages, quantum computing holds immense potential for solving complex problems in fields like cryptography, optimization, and materials science.

In conclusion, computers consist of interconnected components that work together to enable sophisticated computations and provide us with valuable output. From input devices initiating the interaction to CPUs processing instructions, memory units storing data, and output devices presenting results, each element contributes to the incredible power and versatility of modern computers.

The future of computer operations continues to evolve, driven by ongoing research and technological breakthroughs. As we delve deeper into the intricacies of computer architecture and explore new frontiers, the possibilities for innovation and advancement seem boundless.

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