How does a computer work?
From the processor to the memory, take a deep dive into the inner workings of a computer to understand how information is processed. It’s everywhere in our daily lives, yet most people don’t know how it works.
FUNDAMENTALSCOMPUTER SCIENCE
Lucas GRANDIER
5/8/20265 min read
What is a computer ?
A computer is a programmable electronic machine capable of automatically processing data. It operates by executing logical instructions at very high speeds using electronic components.
In practical terms, a computer processes information in digital form in order to:
perform calculations
store data
run software
display results
All operations performed by a computer follow the same principle:
data reception
information processing
production of a result
This process relies primarily on the interaction between hardware and software:
The general architecture of a computer
A modern computer consists of several specialized components that communicate with one another.
The processor (CPU)
The processor, or CPU, is the central processing unit. It interprets and executes program instructions.
The CPU primarily performs three types of operations:
arithmetic calculations
logical operations
data flow management
It contains several internal components:
A processor's clock speed is measured in gigahertz (GHz). The higher the clock speed, the more instructions the processor can process per second.
Random Access Memory (RAM)
RAM (Random Access Memory) is a type of volatile memory used to temporarily store data from programs that are currently running.
It provides the processor with quick access to the information it needs.
For example :
opening a web browser
running a video game
processing a video
All of these tasks use RAM.
When the computer is turned off, the data stored in RAM is lost.
Insufficient RAM causes :
slowdowns
memory overload
applications to close
Data storage
Storage preserves data permanently.
There are two main technologies :
SSDs are much faster because they have no moving parts.
The storage contains :
the operating system
software
user files
The motherboard and communication buses
The motherboard connects all the components to each other.
It contains various circuits that enable:
power supply
data transfer
component synchronization
How data is processed ?
The binary system
The binary system is the fundamental language used by computers to represent and process information. It is based on a base-2 number system, consisting solely of two symbols: 0 and 1, known as bits (binary digits).
In electronic systems, this representation is particularly well-suited because logic circuits operate with two stable physical states:
Power is present (high level) → represented by 1
No power (low level) → represented by 0
This duality makes it possible to design systems that are reliable, fast, and resistant to electrical interference.
A sequence of bits forms a binary code, for example:
These sequences can be used to represent any type of computer data.
All forms of digital information are converted into binary so that they can be processed by the processor:
Text : Each character is associated with a numerical code defined by standards such as ASCII or Unicode
Images : Represented by a matrix of pixels, with each pixel encoded in binary (color, intensity)
Sound : Converted into digital signals through sampling (quantization of sound waves)
Video : a sequence of images (frames) and audio tracks encoded in binary
Peripherals
Peripherals are devices connected to a computer that enable the exchange of information with the user.
There are two main categories: input devices and output devices.
Input devices
Input devices are used to send data to the computer.
For example, the keyboard is used to enter text and commands, while the mouse is used to move the cursor and interact with the graphical user interface.
Output Devices
Output devices allow the computer to display the information it has processed.
The monitor displays images and text, while the printer allows you to print documents on paper.
The operating system
The operating system is the essential software that enables the computer to function. It acts as the link between the hardware components (processor, memory, hard drive, peripherals) and the software used by the user.
When a program is launched, the operating system manages data exchanges and allocates the resources needed for the computer to function properly.
For example, when a user opens a web browser, the operating system loads the program into memory, communicates with the processor, and displays the interface on the screen.
The most commonly used operating systems are:
Windows
macOS
Linux
Without an operating system, the computer's components would not be able to work together in an organized manner.
It performs several important functions:
managing memory and the processor
launching and closing applications
organizing files and folders
controlling peripherals such as the keyboard, mouse, or monitor
ensuring system security and stability
How a computer performs a task ?
When a user performs an action on a computer, several components work together to process the information and display a result. All of these operations take place in a matter of milliseconds.
Let’s take the example of opening a web page :
All of these steps rely on a constant exchange of binary data between the computer’s various components. Thanks to the processing speed of modern processors, these operations seem almost instantaneous.
Conclusion
A computer operates through the collaboration of several components that transform, process, and display information in a very short amount of time. Everything relies on the binary system, which is used to represent data, and on the processor, which executes it.
Memory, storage, and the operating system then manage and organize this data so that the user can easily interact with the machine.
Thus, even though a computer may seem complex, its operation is based on a simple and well-structured logic.
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