Operating system – how it works and why it is worth knowing about it at all.
An operating system is not an abstract curiosity for computer scientists—its basic operating principles can be useful in very practical situations.
Knowing the basics of how an operating system works can be surprisingly practical. Understanding how an operating system works is the foundation of cybersecurity. When a computer suddenly stops detecting a printer or network, or refuses to start, awareness of the roles of the BIOS/UEFI, bootloader, and drivers provides a starting point for solving the problem. In a company, this knowledge also makes it possible to organize the network more effectively: separate guests from employees, control access to files, or require a VPN for remote work.
Additionally, if you are starting to take an interest in vibe coding and running simple programs on your computer, understanding how the system works is absolutely essential.
An operating system is special software that acts as an “intermediary” between a computer’s hardware and the user (as well as applications). When you start your computer, the operating system takes control of its resources: the processor, RAM, disk, graphics card, and input and output devices. Its role is to provide a stable, secure, and convenient environment for running programs.
Table of Contents
CMD Console
Let’s start with the practical aspects. Knowing the console, that is, how to operate Windows using text commands, allows you to do things faster and also provides access to solutions unavailable through the graphical interface. Thanks to it, you will immediately be able to combine theoretical knowledge about the operating system with practical applications.
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How to Launch CMD in Windows
- The simplest way – press the keys
Win + R
, enter
cmd
and press Enter to confirm.
- From the Start menu – click the Start button and type “cmd” or “Command Prompt,” then select the result.
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First Practical Commands
dir
– pokazuje listę plików i folderów w bieżącym katalogu.
- ```
cd folder
– changes the directory (e.g.
cd Dokumenty
).
cd ..
– cofa o jeden poziom w górę.
- ```
cls
– clears the screen in the console.
ipconfig
– pokazuje szczegóły sieci (adres IP, brama, DNS).
- ```
ping onet.pl
– checks whether you have an internet connection.
tasklist
– wyświetla wszystkie uruchomione procesy.
- ```
taskkill /IM notepad.exe /F
– closes Notepad (or another process).
- tree – creates a folder tree view
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The Tree function, while highly visually appealing, displays the entire folder structure as a not very useful vertical tree.
PowerShell
At this stage, you don’t need to know this tool, but it’s good to know that it exists.
PowerShell is a more modern version of the command prompt in Windows. Microsoft created it to give administrators and regular users a tool that is far more powerful than the traditional CMD.
Key Features of PowerShell
- Based on .NET – commands (called cmdlets) work like mini-programs written using Microsoft technology, so they can use system objects and functions.
- Cmdlets instead of simple commands – for example, in CMD you type
dir
and in PowerShell you will use
Get-ChildItem
This makes commands more descriptive and consistent.
- Object handling – CMD returns plain text, whereas PowerShell returns objects that can be further filtered, processed, and combined. This makes it possible to perform complex tasks in a single line.
- Automation – you can write entire PowerShell scripts in files
.ps1
that automatically configure the system, manage the network, or check security.
- Integration with networks and servers – PowerShell can connect to cloud services, manage Active Directory, or configure servers without clicking through an interface.
- Updating computers via a script – administrators can update dozens of computers on the corporate network with a single command.
You can find more about the differences between CMD and PowerShell here.
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Operating system at a glance
System Core
The most important part of an operating system is the kernel. It is the central “brain” that runs in the background and is responsible for:
- processor management (allocating processing time to different programs),
- memory management (ensuring that programs do not overwrite one another),
- device handling (through drivers that translate system commands into a language understood by the hardware),
- process management (starting, suspending, and terminating programs),
- ensuring security (protecting resources and data from unauthorized access).
It can be said that the kernel operates in what is known as privileged mode (kernel mode), with full access to hardware and resources. Ordinary programs run by the user operate in user mode and must request access to resources from the kernel, which protects the computer from errors and abuse.
A good analogy for an operating system is the building of an institution or corporation. The kernel is the chief administrator who sits at headquarters and has access to everything. It knows who may enter the office, how much electricity each floor consumes, which elevators are available, and whether security needs to be called. It makes the final decisions that affect the entire building. Similarly, in a computer, the kernel:
System Layers
Besides the kernel, the operating system contains:
- shell – a text-based or graphical interface through which you issue commands (e.g. a command line or a desktop with icons),
- system libraries and services – ready-made functions that programs can call to, for example, open a file or connect to the internet,
- system applications – configuration tools, file managers, and network management programs.
Types of Nuclei
There are various approaches to building a kernel:
- monolithic – the entire kernel operates as one large program (e.g., Linux),
- microkernel – a minimal kernel that only coordinates basic tasks, while the rest operates as separate modules (e.g., Minix),
- hybrid – a combination of both approaches (e.g., Windows, macOS).
System startup:
1. BIOS/UEFI – first check
After the computer is turned on, BIOS (on older computers) or UEFI (on newer ones) starts first. This software is stored in the motherboard’s memory. Its tasks:
- check whether the basic components are functioning (the so-called POST – Power On Self Test),
- initialize the devices (RAM, processor, graphics card, drives),
- prepare the environment in which the operating system can be loaded,
- indicate which medium the system should boot from (drive, USB flash drive, network).
UEFI is more modern, has a graphical menu, supports a mouse, and allows the use of larger drives than BIOS.
2. Bootloader – “system loader”
When the BIOS/UEFI finds a device containing an operating system, it launches the bootloader – a small program whose sole purpose is to load the operating system kernel into memory. Examples of bootloaders:
- GRUB in Linux systems,
- Windows Boot Manager in Windows systems.
The bootloader can also let you choose which operating system to start (when you have several installed).
3. The Kernel – Takes Control
When the bootloader loads the kernel into RAM, the kernel takes full control of the computer. Initially:
- initializes drivers for basic devices,
- sets the processor operating mode (e.g., protected mode in the x86 architecture),
- starts the first system processes (e.g.
systemd
in Linux or the System process in Windows).
From this point onward, the hardware is no longer managed by the BIOS/UEFI, but by the operating system kernel.
4. Drivers – “Hardware Translators”
The kernel needs drivers, i.e. special modules that translate its commands into the language of a specific device. Example: when you click “print,” the application reports it to the system, the system directs the request to the printer driver, and only then does the driver send the data in a format the device can understand.
5. System Layer – Processes and Services
After startup, the kernel launches various system services:
- in Windows, the so-called services,
- in Linux – daemons.
These are responsible for handling the network, clock, sound, and user logins. In practice, this means that the system is already running and waiting for someone to log in.
6. User Interface – Shell
At the end, the user interface is launched:
- in systems with a GUI: desktop, windows, icons (e.g., Explorer in Windows, GNOME/KDE in Linux),
- in server systems: often only a text console (shell, e.g.
bash
).
The shell is where the user issues commands that are then sent to the kernel.
Summary of the “startup path”
- BIOS/UEFI – checks and initializes the hardware.
- Bootloader – loads the operating system from the disk.
- Kernel – takes control of the computer’s resources.
- Drivers – enable communication with devices.
- System services – provide additional functions (e.g., networking).
- Shell/interface – allows the user to use the system.
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Operating system on a USB flash drive
Using an operating system on a USB flash drive is a way to start a computer without using its hard drive. In practice, this means that the entire system is located on a portable USB device, and the computer starts from it. To prepare such a flash drive, special programs are used, such as Rufus or balenaEtcher, which write the system image in ISO format so that the device becomes bootable. Then, simply change the boot order in the BIOS/UEFI, setting the flash drive as the first source, and after restarting, the computer loads the system from that device.
There are two operating modes. The first is the so-called Live mode, in which the system runs entirely from RAM and the USB flash drive, without saving anything to the disk—making it ideal for testing or rescuing a malfunctioning computer. The second mode is the installation mode, where the USB flash drive simply serves as an installer, allowing the system to be copied to a hard drive or SSD.
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Why Is the System Booted from a USB Flash Drive?
- System installation – the most common use, e.g. installing Windows 11 or Linux.
- Diagnostics and repair – when the system on the drive breaks down, you can boot the computer from a USB flash drive and recover your files.
- Portable system – e.g. Linux Live lets you have your own environment on any computer (useful for administrators or people who work in different places).
- Security – a live system launched only from RAM leaves fewer traces on the computer. This is why, for example, the Tails system is used for secure communication.
Other Operating Systems
Besides Windows, macOS, and Linux, there is a whole range of other operating systems—some of them run on computers, but many are found on other devices, often without us realizing it.
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Android
The world’s most popular mobile operating system, based on the Linux kernel and developed by Google. It runs on smartphones, tablets, televisions, and embedded devices such as car navigation systems.
iOS and iPadOS
Apple mobile systems. iOS powers iPhones, while iPadOS powers tablets. They are closed and tightly controlled, but highly refined in terms of security and hardware optimization.
ChromeOS
A Google system based on the Chrome browser and the Linux kernel. Used in Chromebooks—devices primarily designed for cloud-based work and internet use.
FreeBSD, OpenBSD, NetBSD
The BSD family of systems, derived from UNIX. FreeBSD is renowned for its performance and stability (often used on servers), OpenBSD for its security, and NetBSD for its ability to run on a wide variety of hardware platforms.
Solaris
A system developed by Sun Microsystems and later by Oracle. It is derived from UNIX and used mainly on servers and in professional applications.
QNX
A very lightweight and stable real-time operating system (RTOS). Used in cars, medical equipment, and industrial devices.
Haiku
A system inspired by BeOS from the 1990s. It is developed by the community and features a lightweight, fast graphical interface. An interesting fact for enthusiasts.
Tails
A special Linux distribution focused on security and anonymity. It runs primarily from a USB flash drive and leaves no traces on the computer.
Embedded Systems (RTOSs)
Microcontrollers and household appliances don’t run Windows or Linux, but specialized operating systems such as FreeRTOS, Zephyr, or VxWorks. They power washing machines, routers, robots, and satellites.
Raspberry Pi – a mini computer on which you can install various operating systems
Raspberry Pi is a small single-board computer that fits in the palm of your hand, yet it can surprise you with its capabilities. It was originally created as an affordable educational tool for learning programming and electronics, but today it is used by students and hobbyists alike, as well as in professional projects. Thanks to its low price, energy efficiency, and huge community, the “Raspberry” has become one of the most popular computers in the world. You can turn it into a simple file server, a weather station, a retro gaming console, a media center, or even part of a smart home.
For a Raspberry Pi to work, it needs an operating system—just like any other computer. The most commonly chosen option is Raspberry Pi OS, formerly known as Raspbian, which was developed specifically for this platform. As a result, it is lightweight, stable, and comes with a set of educational tools right out of the box. But you can also run other systems on your Pi: from full Linux distributions such as Ubuntu, through multimedia systems (LibreELEC, OSMC) and retro game emulation (RetroPie), to more specialized options such as Kali Linux for security testing or Windows 10 IoT Core for Internet of Things projects. It is precisely this flexibility—the ability to choose a system for a specific task—that makes Raspberry Pi such a versatile computer.
raspberry pi
Other lightweight systems
- DietPi – an ultra-lightweight Linux distribution, ideal for servers and DIY projects.
- piCore – based on Tiny Core Linux, takes up very little space and boots instantly.
- OpenWrt – a networking system that lets you turn a Raspberry Pi into a router or firewall.
Summary
An operating system is something that usually runs in the background and does not occupy our attention, yet it is precisely what determines whether a computer, phone, or device on a corporate network operates efficiently and securely. In the article, we viewed it from different perspectives: as a “building manager” that allocates resources, as a technical core that takes control of the hardware, and as a set of practical tools—from system services to the CMD or PowerShell console.
This knowledge has a very practical dimension. It helps you consciously care for security, understand the need for updates, and use tools that diagnose problems. It comes in handy when a program freezes, a printer stops working, or a network needs to be configured in a small business. A system on a USB flash drive can save data from a malfunctioning computer, while different systems—from Android, through BSD and ChromeOS, to solutions for Raspberry Pi—show how diverse the possibilities are, provided we know how to use them.
It can therefore be said that the fundamentals of operating systems are a modern form of “map-reading”. Not everyone needs to be an administrator or a programmer, but anyone who understands even a little about how a system works gains greater independence and security. This means less stress and more freedom in using the technology that accompanies us in every aspect of life today.