One PC per person is the approach most companies take when equipping staff with the IT tools they need.

However there are alternatives that can save not just money but the time and effort required to manage all those individual desktop PCs. Here we’ll outline some of the most popular approaches, highlighting the benefits and drawbacks for small businesses. We’ll start with thin clients, also referred to as server-based or multi-user computing.

Thin clients
The term thin client comes from the ability to replace conventional desktop PCs with much simpler, often cheaper, devices. These are typically a lot smaller, with relatively low-spec processors, little memory and, in most cases, no local storage. To the user they look and perform just like a desktop PC and can be used to run the same applications.

However, instead of the processing being done locally, it’s done remotely on a shared, multi-user application server. All the thin client does is process the local graphical user interface (GUI), putting pictures on the screen and relaying the keyboard and mouse actions back to the server.

As well as applications, it’s possible to host the whole user environment this way including, for Windows, the desktop and its shortcuts, icons, user settings and so on. Thin clients can, therefore, be made inherently more secure than a conventional PC with, for example, no local data or program storage and no local user settings to corrupt.

Management is also simplified, with applications installed and managed centrally, and user desktops similarly managed and maintained at the server end. There’s nothing very new about this approach – mainframe and mini computers have always worked this way.

However, Windows was originally developed as a single-user operating system and extra development was required to enable it to cope with multiple thin clients. It took another company, Citrix Systems, to take the first step by porting its OS/2 thin-client technology to Windows back in 1995.

Microsoft has since licensed back the Citrix technology, first for a separate Terminal Server version of Windows NT, before bundling the technology into later Windows Server products.

It has also developed its own Remote Desktop Protocol (RDP) to connect thin clients and terminal servers together, support for which is included in all versions of Windows, along with the Remote Desktop Client, which can access a terminal server from a standard PC.

Although the software to support thin clients is now included in all implementations of Windows Server, additional licensing is needed to use it for anything other than remote server administration.

Hardware requirements
As well as software, hardware is required – to take full advantage of the thin-client approach you need two things: the thin clients themselves and one or more servers with enough processing power, memory and disk space to handle them.

In terms of thin-client devices, the market leader is Wyse Technology. The company offers a wide range of products, including thin notebooks with Wifi support. These are mostly solid-state (no disks or cooling fans) and run either custom software or embedded versions of either Linux or Windows (Windows CE/XP can be employed).

HP also addresses this market with its own range of Linux- and Windows-based products, as do a number of smaller specialist companies, such as Netvoyager.

On the server side there are no special requirements; any industry-standard hardware capable of running Windows Server can be used. Sizing, however, can be a real issue and small-business buyers are best advised to seek the help of a specialist reseller to come up with a suitable specification and number of servers to suit their requirements.

Virtual desktops
In another, more recent development, virtualisation technology has increasingly been added to thin clients to provide a more modern twist. Here the same thin-client hardware is employed, connected to one or more servers over the network. However, instead of shared application servers, each user is connected to their own dedicated virtual machine.

This combination lacks many of the management advantages of the server-based model. Virtual desktops can be managed centrally and new users brought online very quickly, but applications need to be deployed, updated and managed in much the same way as on standalone desktop PCs.

On the positive side, virtual desktops more closely mimic the standard one PC per user model, with far fewer compatibility issues compared with multi-user computing. It can also be more cost-effective, especially given that a lot of the supporting virtualisation products are available free.

Almost any virtualisation host can be used, including the popular VMWare products and those from Microsoft and Xensource (recently acquired by Citrix). VMWare, in particular, promotes this use of its virtualisation technology under the so-called Virtual Desktop Infrastructure (VDI) initiative, which is gaining a lot of industry support.

Wyse, for example, has introduced VDI versions of some of its thin-client hardware specifically to act as a front end to virtual desktops hosted by VMWare servers.

Another twist is the use of real PC blades rather than virtual desktops, such as those from Clearcube, and the mixing together of the two back-end technologies. Further, with additional brokering and management software, both real and virtual desktop resources can be allocated ‘on demand’ to suit the number and type of user connecting to them.

A number of products are available to do just this, including the Hosted Desktop Connection Broker from Leostream and Clearcube’s Sentral. VMWare will also have a similar tool, following its recent acquisition of Propero.

A number of companies offer software to virtualise applications, overcoming many of the deployment, update and management issues associated with standalone apps. Developers include Altiris, now a part of Symantec, Citrix and SWsoft, which changed its name to Parallels. Following its acquisition of Softgrid Microsoft has a foot in this camp, but sees application virtualisation as more of an enterprise technology.

Other alternatives
It’s important to mention some of the other alternatives to the ubiquitous Windows desktop PC. Apple Macs, for example, are widely used by publishing, music and graphics professionals, but are also suitable as a general-purpose, small-business tool. Applications aren’t as readily available but compared with the Windows PC, the Mac is less of a target for viruses and other attacks.

Linux and open-source applications are, similarly, less vulnerable in terms of security and can often be deployed on cheaper desktop hardware than Windows equivalents. Applications are readily available and you will also save money in terms of licensing. Choosing a suitable Linux distro can be difficult and business users should stick with one of the big-name implementations from either Red Hat or Novell.

Unlike some distros, these aren’t available free, but you do get commercial support and access to updates as part of the licence fees charged – and they still cost less than Windows. You can find out more about Linux for the small business here.