Thin Clients

Not everyone is sure just what a “thin client” is. There is no obvious industry definition, though as usual Wikipedia is a useful starting point for an overview.

From our point of view, a thin client should be a small, low-cost and easily managed device which replaces the traditional desktop PC (sometimes described as a “fat client” by contrast). The essence of a thin client is that it contains little or no software nor any moving parts. It should be simple, lean and efficient. Having no software of its own, its job is to act as a display only and to allow its users to access software run on centralised servers instead.

Thin clients come in many shapes and forms for various computing applications. At The Cutter Project we have extensive experience of several types, the choices being driven by our customers' needs. Amongst the most widely used of these are SunRay devices (used in the majority of our deployments) and LTSP thin clients used predominantly though not exclusively in Linux-based environments. Each has a subsection below.

Most of our clients choose a thin-client installation for cost and performance reasons. Attempts to put a cash value on these reasons are harder than it might seem at first. For example, whilst electricity savings on thin clients (around 8 watts per thin client versus 80 to 100 watts for a fat client) in an office or classroom can be guesstimated with a calculator and a recent bill, it's often very difficult to predict total operating and installation costs accurately when:

• Using thin clients may mean no need to use air conditioning.
  • Running costs of air conditioning might seem easy to caculate - so a simple cash figure can be attached to that
  • Infrastructure capital costs of not needing air conditioning in the first place are very much harder to factor in
  • The lack of need for air conditioning may thus make rooms or offices available where air conditioning could never be installed (listed buildings for example). How do you cost that?
  • Where there previously wasn't enough electricity available, again deployment may now be possible when it simply wasn't before. This is very difficult to put a cash figure on.
• Thin clients often have very fast log-in times. Staff can be encouraged to switch them off when they aren't needed, thus changing the patterns of use: fat clients are often left on 24 hours a day because of boot-up times and reliability worries. Energy use patterns then change and simple caculations may be badly out.

Similar difficulties arise when trying to put a bald cash figure on improved reliability, availability and the commonly-found drastic reduction in maintenance staff costs that arise. That's not an excuse for not trying to do the figures, just a note that simplistic “How much will we save” questions are often wide of the mark. Naive calculations may easily prove to be underestimates or miss the point. To illustrate this, we have often found that schools switching to thin client systems are able to release the equivalent of one or two full time technicians who, instead of fixing broken PCs are actually doing something that's educationally useful: there's not necessarily a cash saving but the organisation's goals are being met instead.

Thin clients can deliver much more than just cost savings however. In a world where there is likely to be a mixture of operating systems and applications required, thin clients can break the link between software systems and the desktop device. We have clients where two or more operating systems are in use simultaneously, something which is substantially more complicated if only fat clients are available.

Thin client devices are typically much more reliable than fat client devices and, in the rare cases where replacement is needed, a simple swap by a non-skilled person is often practicable.

Thin client devices typically have a projected life span of two to three times as much as fat clients, reducing procurement costs and spreading capital expenditure over much longer periods. Whilst this in itself can be appealing enough to a typical user it may be even more so to those with a wide geographic range of hard-to-reach ouposts.

Thin clients do not pretend to and should not be used to do every job that a fat client would. Where heavy computational and display usage is required, classically represented by video and sound editing, or where control of hardware is needed such as milling machines or engineering applications, thin clients are simply inappropriate. Anyone considering the use of thin clients needs to be aware of where they are appropriate and where alternatives are a better choice. Cutter Project has a good reputation for thin client installations due in part (we believe) to being realistic about where they make sense and where they do not. We are happy to provide advice on this if you call.

In short - thin clients aren't necessarily just a different form of fat client, they can present a different approach altogether.

SunRay Thin Clients

SunRays are, in our view, thin clients ”done right“. More than just unintelligent display devices they are part of a whole package which provides security and manageability, is sparing of network bandwidth, supports USB devices and, overall, provides an eminently practical and workable package for real-life use.

With SunRays and the associated infrastructure our clients are able to deliver a different kind of environment, not a simple replacement for fat-client desktops. SunRays are often installed alongside Global Desktop remote access facilities, thus helping to eliminate the idea of a boundary between inside and outside the workplace, giving much greater flexibility in hours and places of work.

SunRay installations typically feature log-in times from power-up (or hardware replacement) of a dozen or so seconds. SunRays are completely agnostic about the user's preference for operating systems, being capable of delivering Microsoft, Linux, Solaris, Macintosh or other operating systems and applications as required.

SunRays equipped with smart cards give additional security and configuration options, giving them distinct advantages over many other mainstream thin client devices.

LTSP Thin Clients

LTSP or Linux Terminal Server Project devices are a popular way of converting old or cast-off PC hardware into thin client devices. The most natural fit for these is when combined with Linux or Unix based operating systems but like most thin clients the display devices themselves are not strongly tied to any particular operating system. They work well with, for example, Windows Terminal Services as the “back end” operating system.

Many LTSP installations have been done with particularly restricted budgets and are based on community support models, which should emphatically not be taken as indicating something that's amateurish or second-rate. It's simply an alternative approach to doing things. LTSP clients are often found mixed with other types of thin client hardware as they are relatively simple to mix-and match.

We see LTSP and other special purpose terminal hardware as typically representing an entry level with the SunRay hardware representing a step up in terms of features and manageability.