Steve Ballmer, CEO of Microsoft, has described it as one of the most serious competitive threats to his business. Computer companies as diverse as Sun Microsystems and Dell, Oracle and SAP,

Hewlett-Packard (HP) and IBM are either selling hardware that runs it, or have rewritten their applications to support it.

In just a few years, Linux has gone from a project that was the domain of the enthusiast, the hobbyist and the academic, to a system that is attracting the attention of IT departments in the largest businesses and government departments.

Heads of IT like Linux because of its open source background: users can examine and modify the code for Linux, on the understanding that they share their changes with the Linux community at large. And finance directors like Linux because it offers a break from licence fees and runs on industry-standard hardware that costs relatively little to buy and, according to the general consensus, is not expensive to support or maintain.

This has led to some very large Linux deployments across the whole spectrum of business.

Dreamworks, the film studio, used Linux workstations and servers to render its latest animated movie, Sinbad. Orange, the mobile phone network, runs its databases for content and subscribers in the UK on a Linux system based on Oracle databases and Dell servers. And the city of Munich recently switched over to Linux, replacing a host of Microsoft Windows-based systems.

Linux is no longer the preserve of the amateur.

The next step

Gaining widespread credibility is one thing; establishing Linux as a serious rival to either midrange and high-end Unix variants or to Microsoft’s Windows operating system in the core of a company’s data centre, running business critical applications day-in day-out, is another.

The earliest applications of Linux were at the edge of the corporate network. A simple Linux server, based around a low-cost Intel chipset, is an ideal platform for running web servers, simple departmental database servers, or even security applications such as firewalls or virus scanning.

IT departments were also quick to exploit the similarities between Linux and environments such as IBM’s AIX, HP’s HP-UX and Sun’s Solaris to develop prototypes on Linux. But most moved to more expensive proprietary systems for their production environments.

The next step for Linux has been to consistently challenge Unix and Microsoft in the world of business applications. As projects such as Orange’s Oracle deployment show, real companies are running real businesses on Linux. But the Linux option is by no means an automatic choice for business, and enterprise-scale Linux deployments are not without difficulties.

And as with the first wave of Linux projects, the second (current) wave of Linux initiatives have largely been triggered by the potential for cost savings. But the idea that

Linux systems will always cost less than their proprietary Unix equivalents, or indeed less than systems running on Windows, is simplistic.

“One of the driving forces is certainly cost,” says Dr Frank Baetke, HP’s global technology programme manager for Linux. “But although the support code is free, support itself is not. There is the adage that ‘Linux is free, if your time is worth nothing’, and all the professionals know that there is truth in that.”

Computer science versus the penguin

Another accepted truth about Linux is that it has primarily done well in environments that scale horizontally. Specialist Unix environments and even mainframe computers continue to attract new business users where vertical scale is critical. The difference goes to the core science of how high performance computers work.

Applications such as Oracle’s 9i RAC – perhaps the program that has done most of all to persuade companies to try Linux for critical work – work well with Linux because the workload can be spread over a cluster of low-cost, relatively low-powered computers, each with its own memory. The cluster approach also works in medical, pharmaceutical and geological research where processing can be broken down into smaller tasks and shared between computers.

Applications that need a large amount of memory in one place work best on single large computers with many processors, all sharing memory space. For transaction-intensive business applications where speed is critical, such as supply chain management, financial processing or manufacturing, the one big box approach still has real advantages. “These environments also have very sophisticated technical features that you find in professional Unix, but which are not even on the roadmap for Linux,” admits HP’s Baetke.

His views are echoed by his counterparts at Sun, which announced last year that it would invest heavily in Linux technology to complement its Sparc-branded RISC (reduced instruction set computer) chips and its Solaris-branded version of Unix.

“The Sparc architecture is highly optimised: it is one of fast, big processors,” says John Gage, Sun’s chief scientist. “We are focusing on processors that have multiple cores on the same silicon. We want to be able to support multi-threading.” He suggests that Linux, which today runs on the relatively simple Intel Pentium processor, is a long way from supporting such capabilities.

Chipping away at RISC

While there may be gaps in Linux’s capabilities today, the operating system already offers performance that is sufficient for a growing number of mainstream business applications.

Linux was, of course, written specifically for Intel-based machines, and it has benefited from Intel’s ability to squeeze significant performance gains from its 32-bit microprocessors. The total cost of ownership of Linux systems has also benefited from the huge economies of scale that Intel enjoys. In hardware terms at least, it is hard for other computing standards to compete.

“Intel hardware has become more and more competitive and powerful, and Linux on Intel is now a very stable and reliable platform,” says David Valentine, IBM’s Linux sales director in Europe, Middle East and Africa. “Businesses have taken a lot of the commoditised computing and moved it to Linux on Intel.”

Where all that leaves Microsoft’s famous alliance with Intel is unclear. The most politically charged debates have tended to focus on the ability of Linux to compete with Microsoft in the server sector, and even to make inroads into the software

giant’s dominant position on the desktop. But claims that Linux will somehow destroy Microsoft’s business are overdone. Organisations migrating to Linux are more likely to have switched from other Unix platforms, since it is cheaper and easier than migrating from a Windows environment.

“Our customers are coming from traditional Unix environments,” says Kevin Libert, Dell’s European general manager for enterprise systems. “They are comfortable in that environment and the porting effort is minimal.”

Libert says that after web hosting, the next largest market for Linux systems is where companies have written bespoke applications, and so own all the code. “These companies often have highly technical staff, so they can move their applications right over [to Linux] and save quite a lot of money in the process,” he says. Companies that use Windows-based applications are far less likely to have developed them in house, so the move to Linux would be more painful.

Commodity OS?

The progress of Linux is not only changing the dynamics of the server industry; it is also changing the way the IT industry prices its software.

Some applications, such as MySQL, the open source database, are now downloadable from the Internet. The Linux distributors are also including more software with the basic Linux code: most distributions of Linux for Intel desktops now include either Sun’s StarOffice or OpenOffice, from OpenOffice.org, for example. And this trend is being mirrored in large business systems, as companies seek to differentiate their products. All of the major enterprise computing companies have a ‘Lintel’ range, and buyers are looking increasingly for additional services or software as part of the deal.

Red Hat, one of the leading distributors of Linux, has an Enterprise Linux software range that offers professional-level support and additional tools, such as clustering. Meanwhile, Unix companies, such as Sun, are bundling more and more software with their core operating systems. Sun’s Orion project will include a range of enterprise-level software tools, such as web serving, messaging servers, clustering and security. Sun is making the Orion package available for both Solaris and Red Hat Linux.

Given the similarities between Linux and the core of most traditional Unix operating systems, it is entirely possible that computer manufacturers will increasingly turn their attentions away from the basic operating system and focus instead on adding additional functionality and ‘middleware’.

In turn, independent software vendors might choose to write their applications for Linux rather than all the specialist variants of Unix, especially as a number of Unix vendors claim their operating systems will run Linux programs.

“It has always been expensive for software vendors to support different flavours of Unix,” says HP’s Baetke. “They will tend to focus on a standard. In technical terms, they will write for a Linux application’s binary interface, as this will give them the widest range of customers and platforms.”

This could, in effect, force the main Unix vendors to sell their systems as ‘Linux plus’ or ‘Linux compatible’, with the core operating system effectively standardised, and buyers paying extra for either middleware or additional features such as security.

Unlikely? Maybe, but given the progress Linux has made over the last few years, the idea should not be dismissed.