This month marks the 25th birthday of open source operating system Linux and it is hard to over-estimate the impact it has had on the world of technology.

In August 1991 university student Linus Torvalds announced he was working on a UNIX clone which: “won’t be big and professional like gnu”.

Within a year a rather wobbly first version was available. But what made it different was the way it was licensed. The code was freely available for anyone to improve on – provided they passed on any improvements they made.

It wasn’t the first free software license but it was the one which really took off and led to a revolution in the way people thought about software development. At the time the vast majority of software code was a closely-guarded secret – even the biggest business customers were not allowed to see the code beneath the applications and operating systems they bought.

This led to a risk for big companies making large software purchases – if their supplier went bust there was no way they could continue to develop and maintain the software they had bought and now relied on. Some companies offered agreements where the source code was kept in a virtual locked vault and could only be accessed by customers if the software company closed down.

This world of secrets meant thousands of hours were spent effectively re-inventing the wheel – addressing problems which had already been solved by other developers working for other companies, or sometimes even just working for a different division of the same company.

For software companies this meant they were all chasing the same limited number of programmers. The big software companies spent lots of money recruiting the best developers and keeping them happy.

It meant software development was a slow, centralised and clunky process.

But because of the open source license Linus Torvalds had inadvertently created a huge development team, all working for free, within just a few months.

The Linux kernel developed in tiny steps with the help of a growing army of volunteers. It improved gradually but relentlessly. People gave their time and welcomed the chance to learn as they did so.

There was an element of luck to this – what could have been rival UNIX operating systems were stuck in legal battles which gave Linux a valuable head start.

Torvalds’ engaging modesty and lack of ego was clearly important too.

But what began life as the favourite operating system of hackers, students and academics has shifted to the absolute centre of enterprise technology.

Today it is almost impossible to do anything at all online with out interacting at some point with a Linux machine.

W3Tech surveys of accessible web servers in August found 36.3 per cent were using Linux.

And all the truly massive online players – like Amazon, Facebook and Google use Linux to power their services.

As these companies use Linux so their developers continue to develop and improve it. All the big hardware companies, which use Linux on the servers they sell, also contribute to improving the underlying code.

All of the world’s top ten most powerful supercomputers use Linux. But Linux also powers ‘simple’ devices like embedded devices, TV set-top boxes, Chromebooks and Android phones.

Linux is being adopted for use in the Internet of Things – not necessarily in the simple sensors at the edge but in the intelligent devices needed nearer the centre to collect and analyse data from such devices.

The operating system has moved from servers down to the mobile devices in our pockets and along the way has entirely changed the way software is developed and much of the business world is organised.

It has meant massive changes for the way we work. Linux developers co-operated informally, around the world, and gave away their work for free.

In the early days Linux epitomised this ‘hacker culture’: it was anti-commercial and vehemently opposed to the stranglehold of the handful of big corporations which dominated the software market at the time.

But today there are thousands of companies making good money from Linux. They offer bespoke software for businesses, ongoing support, hosting and all the other associated services which enterprises need to turn software into business solutions.

Linux has also had a big impact, helped by the internet, on how millions of other people work – people who have nothing to do with software development. Working in virtual teams, which may be spread around the world, is now a normal part of corporate life.

The idea of this sort of collaborative working continues to gain ground when compared to traditional, centrally controlled, top-down management structures.

It has also played a role in the changing way business competes and works together. In the early 1990s Linux was seen as a serious threat by the major software companies. Now they all work with Linux to varying extents.

In the same way enterprise technology is no longer built around single vendors but on groups of providers which work together.

Admittedly not the whole world has gone Linux – although Linux, in the form of Android, has conquered a good slice of the mobile market – it has never really been adopted by desktop users despite dozens of attempts.

This is despite Torvalds first developing Linux for his own desktop machine.

In a recent interview with the Institute of Electrical and Electronics Engineers’ Spectrum magazine Torvalds said user inertia was one reason for the slow adoption of Linux on desktop machines.

Torvalds said: “The desktop is in many ways more complex, with much more legacy baggage. It’s a hard market to enter. Even more so than with a cellphone, people really have a certain set of applications and workflows that they are used to, and most people will never end up switching operating systems—the number of people who install a different OS than the one that came pre-installed with the machine is pretty low.”

He said that although the desktop market remains important the market for the general-purpose desktop machine is fading and there is an increasing role for specialised devices – including smartphones, handhelds, tablets and netbooks – where Linux enjoys a larger share of operating systems.

Some observers believe the move to reliance on cloud services, which are mostly run on Linux, will make it easier for an open source desktop client to gain market share.

The whole interview is here:

http://spectrum.ieee.org/computing/software/linux-at-25-qa-with-linus-torvalds

Asked about the future of Linux Torvalds said recently (https://youtu.be/tQKUWkR-wtM) that there had never been any sort of long-term plan. Instead they’d focussed on solving immediate problems – “if you take care of the details then the big picture follows”. Which is a pretty good description of how almost all software is developed today.