How Linux has influenced modern IT

On 25 August 1991, Linus Torvalds released the Linux kernel. We look at how the open source operating system has evolved in the last quarter of a century

This article can also be found in the Premium Editorial Download: Computer Weekly: 25 years of Linux

A quarter of a century is a long time in IT, but Linux, which has turned 25, is now at the heart of many hugely successful enterprises.

Martin Percival, senior solutions architect at Red Hat, said: “Linux was regarded as an alternative to proprietary Unix. But RHEL switched it to becoming an alternative to Windows Server.”

In the early 1990s, after Microsoft’s famous divorce from IBM, the software company decided to go it alone and develop its own operating system. Windows 3.x became the de facto standard for the PC desktop, while the IBM rival OS, OS/2, failed to gain much traction.

But as PC chips became faster and Intel’s first proper 32-bit processor, the 80386, saw success, Microsoft embarked on a project to get into server computing, the domain of the Unix machines.

Meanwhile, in Helsinki, a 21-year-old Finnish student, Linus Torvalds, began working on an operating system that could take advantage of some of the advanced features that 80386-powered PCs had to offer, such as the 32-bit instruction set and paged memory.

The PC became so successful because it represented the so-called industry standard architecture, on which operating systems and application software could run. But as it became more complex, more and more device driver software was needed to connect sound cards, display adapters and network ports. And all of this software needed support.

According to Percival, Windows NT server had as much of a challenge as Linux in supporting the range of hardware the operating system could support. “Microsoft did a very good job on certification,” he said.

Similarly, companies such as Red Hat and SuSE created Linux distributions, which were certified to run on specific hardware.

Percival added: “One of the reasons that businesses jumped in was because Red Hat produced a range of certified devices.”

Read more about enterprise Linux

Although it started out as an alternative to Unix, Linux has evolved into a robust enterprise operating system.

Without the world of open source and Linux, we would not have the kind of scale to run a cloud. While many supporters argue that cost should not be the main reason for choosing open source, Percival said: “Imagine trying to use a Tandem NonStop system to run Netflix. You would never afford to buy it.”

In the past, a premium server like NonStop would be used when extremely high availability was a priority. Such systems were very expensive. Today’s IT architectures achieve high availability at a much lower price point by using large numbers of commodity Linux servers instead of one highly resilient box.

So, for the enterprise, Linux has provided a low-cost base platform on which to run large internet applications, mainly as an alternative to proprietary Unix systems.

Hot patching

In a blog post earlier this year, Forrester analyst Richard Fichera described how hot patching was now available on SuSE Linux, giving the OS a level of maintainability usually available only on mainframe systems.

In the post, he predicted this would become a standard feature of the Linux kernel. “It is almost certain that a future release of the 4.x kernel will contain production-ready hot patch as a standard feature, placing the burden on the Unix providers to prove they can keep up with Linux,” he said.

According to Fichera’s blog, neither Oracle (with Solaris), IBM (Aix) or HPE (HP-UX) have developed equivalent capabilities in their respective versions of Unix.

What is also interesting is that Linux was also pitted against Windows, and some organisations, such as the city of Munich, made public commitments to move to open source, even running desktop Linux rather than Windows PCs.

This is something that Linux distributor Ubuntu continues to push, said Jane Silber, CEO of Canonical, which supports Ubuntu. “While the cloud runs almost entirely on Linux, we think the desktop remains an important focus for Linux innovation, too,” she said.

Enterprise focus

To compete with Windows and commercial Unixes, Linux has had to become more palatable to business. Thanks to the efforts of organisations such as SuSE, Red Hat and many others, Linux is very much a part of the enterprise. Their efforts, and the licensing frameworks from the GNU Foundation and Apache Software Foundation, have paved the way to making open source and Linux powerful forces in modern computing.

Jonathan Bryce, president of OpenStack, said: “OpenStack has followed a similar path to Linux and we learnt from Linux.”

Specifically, said Bryce, in the mid-1990s, Linux was a very tech operating system, but from 1999 there were commercial efforts to make it accessible and trusted by enterprises.

It not only replaced Unix servers, but has also been used when Windows servers failed. Dave Rosenburg, senior vice-president at the Linux Foundation, said: “Whenever there was a dead or dying Windows box, we used to put Linux on it. Our web servers were pretty low-powered machines, but they had 100% uptime on Linux. The Windows NT server would fall over within four hours.”

Who would have thought, 25 years ago, that Linux would cement itself as the de facto standard for running highly scalable cloud infrastructure in state-of-the-art datacentre computing? Linux has clearly come a long way, and in doing so, it has established open source as a sound alternative to commercial software, suitable for the smallest to the largest organisations on the planet.

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