Operating Systems: An Introduction
An operating system (OS) is the software layer that provides multitasking and lets you control the basic functions of a computer. Without an OS, a computer would be extremely difficult for people to use.
The OS allows you to do things such as:
- Sign in with a username and password
- Sign out and switch between users
- Format storage devices and set default levels of file compression
- Install and update device drivers for new hardware
- Launch applications like word processors, browsers, or games
- Set file permissions and manage hidden files
- Close or restart misbehaving applications
The Kernel
At the heart of every OS is the kernel—the core that manages files, memory, processes, and device drivers. The kernel communicates directly with the hardware. It sits just above the firmware (such as BIOS or UEFI), which is not officially part of the OS.
Popular Operating Systems
The most widely used desktop OS is Microsoft Windows, especially Windows 10 and Windows 11. On servers, Linux is very common because it is powerful and highly customizable. Other important operating systems include MacOS, ChromeOS, Android, and iOS.
Many people use more than one OS. This can be done through dual-booting or by running a virtual machine. For example, a developer might prefer Linux for programming but Windows for gaming.
Interfaces: CLI vs. GUI
An OS must provide a way for the user to interact with it, called the user interface (UI). There are two main types:
- Command line interface (CLI): text-based commands typed into a console or terminal
- Graphical user interface (GUI): windows, icons, and menus controlled with a mouse or touch
Most users work mainly with GUIs, but CLIs remain essential for system administrators and software engineers. In Windows, the CLI can be accessed through Command Prompt, PowerShell, or the modern Windows Terminal. Command Prompt is a descendant of MS-DOS, while PowerShell offers advanced scripting. In MacOS and Linux, the CLI is usually the Terminal running Bash or another shell.
Unix and Linux systems support multiple GUIs. Two popular ones are GNOME and KDE. Traditionally these have run on the X Window System (X11), but newer systems are increasingly adopting Wayland.
Extra Features
Modern operating systems often come with built-in applications such as text editors, calendars, and web browsers. On desktops and laptops, this gives users a ready-to-use system right after installation. On mobile platforms like Android and iOS, the preinstalled apps are basic, but the app ecosystem provides thousands of extra tools and games that can be downloaded easily.
Example: Ubuntu Linux
Ubuntu is a well-known Linux distribution. It is free to download, includes office software and multimedia tools, and makes it easy to add new software through package managers. With a few clicks, you can install thousands of applications for free. Ubuntu is popular on desktops and laptops and is also widely used on servers, alongside other Linux distributions such as Debian and Red Hat Enterprise Linux.
Why It Matters
As an IT professional, you will probably need to master more than one OS. Learning them inside-out gives you the ability to perform a wide range of tasks in an efficient manner.
In conclusion, the operating system is a foundational software layer that shapes human-computer interaction (HCI), and this makes it especially important to study and understand.
- Which operating systems have you tried? Which do you like best? Why?
- What users typically prefer CLI operating systems? What users typically prefer GUI operating systems? Why?
- Research a few of the following operating systems and write a short essay: Windows, MacOS, Android, IOS, and Linux.