Why So Many Operating Systems?

About this interactive

Why are there so many operating systems, and why do some look alike? The kernel, the part of the operating system that talks to the hardware, is the hardest part to write. So a company that wants its own look and feel usually borrows a kernel and puts its effort into the user side: the front end and the apps. Android was made that way from the Linux kernel. Keep the kernel, change the user mode and apps for a new device, and you have another variant. There is a cost. Each family has its own kernel and user mode, so an app has to be built separately for Windows, for Apple systems and for Linux. The history explains Linux's place. Unix had to be licensed from Bell Laboratories, Berkeley's BSD started from licensed Unix code, and many Unix-like systems copied how Unix works without its code. In the early 1990s Linus Torvalds wrote Linux as a free, open, Unix-like system, and it is now the base of a long list of distributions (distros). A distro that branches off another reuses much of its code, so distros on one branch work in similar ways, and a single distro such as Fedora comes in versions for a workstation, a server or an IoT device. Microsoft does the same inside one family: Windows Server runs the same NT kernel as Windows 11, with a plainer look built for performance, a different set of services, and server roles such as DHCP and DNS ready to install.

What you'll learn

Predict how operating system variants come about and what they cost: a maker borrows a kernel and builds its own front end and apps, and an app needs a separate version for each operating system
Predict what changes between versions of one family: Windows Server against Windows 11, and Linux distributions on one branch or in different editions

Aligned to

CompTIA Tech+

3.1 Explain the purpose of operating systems.

2.6 Compare and contrast common computing devices and their purposes.

CompTIA A+ Core 2

1.8 Explain common OS types and their purposes.

1.1 Identify basic features of Microsoft Windows editions.

Key terms

Kernel: The core component of an operating system that manages hardware resources, process scheduling, and memory, operating at the highest privilege level and separating user-facing processes from direct hardware access.
User Mode: A restricted execution state in which applications and user processes run, isolated from direct hardware access.
Distribution: A variant of Linux built by combining the Linux kernel with a user-mode environment and applications to create a distinct operating system release.
Unix-like: An operating system that mimics the behavior and design of Unix without being a direct derivative, such as Linux.
Server Role: A specific function or service installed on a Windows Server, such as DHCP or DNS, that enables the server to provide that capability to network clients.
Server: A computer or program that provides services or resources to other devices, known as clients, over a network.

Topics

Kernel User Mode Distribution Operating System Interactive Predict

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