Last year was the 25th anniversary of the PC.

For all but the first two or three of those years, the Intel-based, Microsoft Windows-driven and IBM-architected desktop platform has been the de facto standard means of delivering IT services to corporate end-users. How much longer, however, the PC can retain this position remains to be seen.

It is still too early to talk about the death of the corporate PC, but that is not the same as saying that its future is secure. On the contrary, in the past several years two trends have emerged that have placed serious questions marks against the PC’s future: the increasing complexity and relative cost of corporate PC management; and the growing number of increasingly viable alternatives.

Certainly, for many corporate users that once enthusiastically embraced its relative simplicity and inexpensiveness, the PC has already lost most of its original charm.

The average business PC purchase price (currently around $750) may continue to fall, and the “value” it delivers still increases with each iteration of Moore’s Law, but the cost and complexity of operating PC estates keeps on rising. Gartner now estimates the lifetime cost of an average business PC at $4,000, and this doesn’t factor in opportunity costs connected with PC security breaches and downtime.

Having once been the most dynamic and cost-efficient element of corporate IT infrastructure, the PC is now often the biggest cause of cost and inflexibility. Somewhat ironically, it is a situation that stands in stark contrast to developments in the server environment. Here, the twin trends towards server consolidation and virtualisation have reinvented data centre economics, and turned formerly intractable legacy systems into an apparently infinitely flexible and seamless set of processing resources.

The good news is that the same technologies that have revolutionised server economics are now also starting to impact the desktop. Indeed, thanks to the deployment of a variety of virtualisation-based strategies both the PC and the desktop are in danger of being redefined altogether.

So far the most common of these desktop virtualisation techniques is hosted PC virtualisation. This approach uses a virtual machine manager, such as VMWare’s GSX Server, to host multiple guest operating systems on a conventional operating system, such as Windows Server or Linux. In this way multiple PC images can be hosted on a single physical machine, offering the best of both worlds to users and managers alike.

Now, end users can still have the same individually tailored application stack that they have come to expect from a desktop machine, but IT no longer has the headache of maintaining hundreds of remote, distributed machines that are inherently insecure.

All other virtual PC techniques are variations on this basic approach, and each has its own particular strengths and weaknesses. Hosted PC, for instance, is a relatively resource greedy technique, and is generally held to impose a 25% performance penalty against hosted applications – although this can be substantially reduced depending on the power of the hosting server, network connectivity and other variables.

In contrast, hyper visor based PC virtualisation – which multiply PC software stacks directly against a bare metal server – delivers better performance, but at the cost of heightened system integrity risk.

Ultimately, virtualisation pro-ponents, such as VMWare’s chief scientist and Stanford University Professor, Mendel Rosenblum, argue that today’s performance and security concerns are merely teething problems. Indeed, Rosenblum expects performance differences to almost entirely disappear as more virtualisation is done directly against the underlying processor.

After all, he argues, most of today’s performance and security problems stem from the unwieldy and legacy-bound nature of modern desktop operating systems. So, once the services currently performed by the operating system are passed to virtual machines running directly on a chip, there is no more need for an operating system, and no more sources of security flaws and redundant instruction cycles.

Whether predictions of PC virtualisation’s future capabilities are accurate or not already hardly matters. PC virtualisation software sales are growing strongly on the back of success stories like Dundee City Council, which claims to have reduced its annual support bill by 150,000 by deploying PC application virtualisation software, and can only be accelerated further as more virtualisation technology arrives in the market by default.

Already, for instance, Microsoft is preparing to ship the Long-Horn version of Windows Server, which will feature a built-in virtual machine manager, and thanks to Intel and AMD, Gartner expects 75% of PCs to have hardware support for virtualisation built-in by 2010.

Of course, there are bound to be drawbacks. As some server virtualisation pioneers have already discovered, virtual server sprawl can be every bit as pernicious as physical server proliferation, prompting Gartner analyst Brian Gammage to observe that: “the complexity of managing the solution that removes the complexity of something else is something we often overlook”.