Today marks the 25th anniversary of the Linux operating system!

More specifically, it marks the day that Linus Torvalds announced his new operating system (that was later called Linux) in a newsgroup post:

From:torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)
Newsgroup: comp.os.minix
Subject: What would you like to see most in minix?
Summary: small poll for my new operating system
Message-ID: 1991Aug25, 20578.9541@klaava.Helsinki.FI
Date: 25 Aug 91 20:57:08 GMT
Organization: University of Helsinki.

Hello everybody out there using minix-

I'm doing a (free) operating system (just a hobby, won't be big
and professional like gnu) for 386(486) AT clones. This has
been brewing since april, and is starting to get ready. I'd like
any feedback on things people like/dislike in minix; as my OS
resembles it somewhat (same physical layout of the file-system
due to practical reasons)among other things.

I've currently ported bash (1.08) an gcc (1.40), and things seem to work.
This implies that i'll get something practical within a few months, and I'd
like to know what features most people want. Any suggestions are welcome,
but I won't promise I'll implement them :-)

Linus Torvalds torvalds@kruuna.helsinki.fi

So what is Linux?

Linux is a free and open source operating system that runs on millions of computers and devices today. But in order to understand what that means, let’s start by looking at how Linux came to be…

It started with UNIX, FSF, GNU and the GPL

The UNIX operating system (which ran on the most powerful computers in the world in the 70s and 80s) set the stage for Linux. Unfortunately, UNIX software was incredibly expensive because companies that developed it knew they could charge a lot for it and get away with it. In 1983, Richard Stallman started the Free Software Foundation (FSF) to encourage computer science students and freelance software programmers worldwide to develop free software for the UNIX platform. Richard believed that the sharing of ideas would result in faster software development, and during the late 80s, he created the GNU Project, whose sole aim was to create a free UNIX-like operating system (GNU stands for “GNU’s Not UNIX”).

While the GNU Project never came to fruition (too ambitious), it led to the creation of the GNU Public License (GPL). If a software developer publishes their software under the GPL, they have to make the source code (the actual programming code) for the program freely accessible to anyone. And if other people modify that source code in order to make the program better, they are legally bound to make that modified source code available to anyone……keeping the software freely available forever! We now call this type of software open source software, and there are a number of open source software licenses available that people can choose from.

Enter Linux

In 1991, Linus Torvalds created an improved version of MINIX (mini UNIX) for the Intel PC platform (x86) that was eventually called Linux.

And to keep it free, he released it under the GPL!

Since then, several thousand open source software developers in the worldwide UNIX community have transformed Linux into a very sophisticated operating system. Linus Torvalds and his team develop the operating system kernel and libraries in California; however developers worldwide develop the libraries and software packages used with the Linux kernel. You may obtain different distributions of Linux as a result - all distributions share the same kernel and libraries, yet have different software packaged with the kernel. There are hundreds of Linux distributions available; some common ones include Red Hat, Fedora, SuSE, Debian, Ubuntu and Gentoo. Even Google’s Android is just Linux in drag!

Linux everywhere!

Because it is open source, Linux has been adapted to run on pretty much any type of hardware, making it the most diverse operating system in existence today! While you may not run Linux on your desktop (most people use Windows or Mac OS X), you probably still interact with Linux every day. Android phones run Linux, and so do most Web servers on the Internet (e.g. Google, Amazon, your online banking site, etc.). Nearly all embedded hardware systems (e.g. bank machines, in-car audio systems, GPSes, eBook readers) and large supercomputers run Linux too!

It’s important to note that Linux is basically an open source UNIX operating system – nearly all of the concepts, commands, and files are identical between UNIX and Linux. If you know Linux, you know UNIX and vice versa.

I should also note that UNIX is still around today. If you use a Mac computer or iPhone, you are using a UNIX operating system (Mac OS X and iOS are both UNIX operating systems). Similarly, many embedded hardware systems and network devices (such as routers) run some type of UNIX, as do many large server systems (e.g. BSD UNIX, Solaris UNIX, and so on.).

I’m definitely no stranger to Linux.

In fact, 13 of the 17 published academic textbooks that I’ve authored are on Linux, including my best-selling Linux+ Guide to Linux Certification, which is used in colleges and universities worldwide and now in its 4th edition.

I wasn’t always a fan of Linux – in the 90s, I was a hardcore UNIX user and developer, and when Linux came out, everyone was like “check out this FREE UNIX called Linux”. The only problem was that Linux was painful to install at best, and wasn’t that impressive afterwards. It wasn’t polished by any definition, and had few tools - so we never took it seriously and promptly moved back to our coveted UNIX systems. And besides, if you wanted to install a free UNIX (polished, full of tools), you could install BSD UNIX at the time!

Of course, all of that changed around 2000. By then, Linux was a full-fledged operating system with massive support from the developer community. Companies surrounding Linux were popping up everywhere, and Linux servers were spreading like wildfire. By the mid 2000s, Linux was widely considered the most powerful server operating system, and development focus shifted to include making it a polished client and mobile operating system as well.

Today, Linux is an incredibly polished and powerful OS that runs anywhere and everywhere. And because it’s open source, it’s only going to get better and better in the future. I wouldn’t be surprised to see Linux continue as the dominant operating system in 50 years!