Thin-client computing fattened up

The thin client is a simple tool for any large business, and made mass network computing possible even before practical networks existed.

Today, in the age of a fat PC on every desktop, the thin client continues to play a major role in both mainframe and client server computing.

The mainframe has slipped in and out of fashion, but the thin client has continued as a significant part of IT infrastructure.

But the technology has steadily evolved from the early days of green screens, RS232 data connections and ANSI, VT-100 and VT-52 terminal protocols.

Modern thin clients are more likely to use standard IP networking than serial connections, and the dull green and amber displays have long since been replaced with full-colour screens and graphical, mouse-driven interfaces akin to Windows.

Researcher IDC predicts that annual shipments of corporate thin-client devices will grow from 929,000 in 2000 to more than 4.8 million by 2004, highlighting renewed demand.

But what's behind this market growth? IDC says that IT managers, under constant pressure to reduce costs while improving access to enterprise data, will "continually evaluate desktop purchases" to determine which system delivers the best price/performance ratio.

As thin-client adoption rates increase, the benefits and cost advantages will become increasingly apparent to the IT community, prompting further market growth.

Thin clients make dealing with legacy back-end systems much easier, reducing the need to recode data and transfer it to modem servers.

Finally, the growth of high-bandwidth solutions such as DSL and cable modems will also spur the adoption of thin client computing.

In the past, IT managers feared that moving applications away from the desktop would be a drag on network performance.

But the availability of high-bandwidth external connections, and the falling cost of Gigabit Ethernet, have made thin clients an attractive option.

Why buy a thin client?
As conventional fat PC prices fall, you may be wondering why you should purchase a thin client at all, even if it is below £500 a seat.

But it's important to understand that the benefits and cost savings associated with thin-client and server-based computing are maximised when you use the devices on the desktop, where the thin-client hardware unit can continue to outstrip the cost of even the cheapest Windows PC.

By eliminating the moving parts (disk drives), local applications and fat operating systems from the desktop device, client management and maintenance becomes centralised, cheaper and less prone to failure.

For businesses, it is attracting attention because of its ability to solve some of the most vexing problems facing IT: the staffing shortage, data privacy and security, and the quest for value from technology purchases.

Nevertheless, thin clients are still widely misunderstood. For example, many IT managers hesitate to implement thin-client solutions through fear that end users will resent the loss of their personal hard drives.

And, despite evidence to the contrary, some worry that network performance will suffer when processing is moved away from the desktop and across the network back to the server.

Stephen Yeo, director of marketing at thin-client manufacturer Wyse Technologies, said: "Weaning business staff off PCs is a cultural challenge, because the systems are regarded very much as a status symbol: evidence of personal prestige and power equivalent to the company car.

"To win staff acceptance of thin clients, it may be necessary to sneak systems through the back door. Dixons has a policy in some parts of its company whereby all employees have thin clients unless they can justify that their role requires a PC.

"However, this approach calls for sensitive management to avoid staff resentment."

This kind of working model can also be used to preserve business continuity in the face of a systems or power failure.

As Yeo explains, the thin client model, combined with some form of network or internet connectivity, can provide a means for a workforce to work off a remote back-up or mirror of the core business data and applications.

"A softer alternative would be to provide staff with cheap thin clients and a dial-up modem to the corporate network for home use," he explained.

"Once tried, staff are more likely to accept thin clients as equivalent PC work tools in the office.

"This is a smart move anyway because, if your company suffers some kind of outage or other problem that prevents use of its normal premises, staff can work from home from the mirrored back-up data centre and business continuity remains unaffected."

What goes into thin-client computing?
In addition to the hardware that sits on the desktop, server-based thin-client computing requires three elements: an operating system environment that can support it (Windows, Citrix, Unix and Linux are the most common); technology that offers IT greater control over network traffic; and centralised application and client management software.

Thin clients are a flashback to the mainframe era before computing was pushed out to end users in the form of PCs.

The problem with using PCs, as anybody who's ever worked on a helpdesk knows, is that users get themselves and the company in all sorts of trouble through using unauthorised applications and downloads.

Returning control of the applications to central servers maintained by knowledgeable IT staff makes a big difference.

Centralising all the core functions of processing, disk storage, memory, applications and operating systems shifts the requirement for performance significantly, with the entire burden being placed on one or more back-end servers.

While this often results in the purchase of highly expensive and component-heavy servers, the fact that the resources for hundreds of users are in a single location makes the continual process of upgrading software, creating user accounts, flushing redundant user desktops and managing storage more efficient and cost effective.

Fewer people are needed to manage systems and there are far fewer trips to the user's desk, because the thin client itself normally can't be tampered with by the end user.

Windows and thinner clients
Microsoft's NT4 operating system was the first Windows OS to really lend itself to the idea of thin-client computing, until the arrival of Microsoft Terminal Server.

While third-party companies such as Citrix have developed more powerful and popular terminal services and thin client/fat server systems, Terminal Server is a cheap and integrated route to Windows' thin and thinner client computing.

Using a small-client application, or more recently a web browser window and an applications service provider plug-in, users can launch a functional and centrally controlled desktop environment, with all processing carried out remotely and only the screen display data being sent to and from the client device.

Windows 2000 developed the Terminal Services format further, creating a more stable and functional system with some optimisation for remote hosted application hosting.

With the introduction of Windows XP last year, Microsoft took the desktop deployment of Terminal Services yet further by making a version of the Terminal Services client application (under the name Remote Desktop Connection) a standard feature of both the Home and Professional versions of Windows XP.

But, for the pure thin client, the popular approach for those wanting to retain some kind of Windows environment is to adopt hardware running either embedded NT (or XP) or a stripped-down version of the Windows CE operating system, traditionally used on PDAs and more recently on smartphones.

"Under pressure to cut costs dramatically without sacrificing business goals, IT managers face three stark choices," explained Yeo.

"They can either stay fat using their powerful desktop PCs and pay the high price of doing so, fatten up further by deploying Windows XP, or thin down completely to thin clients running XP Embedded [Xpe] and gain advanced business benefits.

"XPe allows you to embed applications into thin clients just like a solid-state PC, but with no moving parts. Such systems support a very powerful web browser, all plug-ins and most peripherals.

"This hybrid architecture is ideal if you want all the flexibility and power of PCs, but all the cost advantages of thin clients."

The thin client route saves 30 per cent of the total cost of ownership of the average IT budget compared with a PC strategy, delivering payback on migration based on IDC figures within three to eight months.

It also supports tighter security and management controls and easier IT change management, while running a powerful business operating system.