Thin Clients

From time to time you may have heard IT people talking about “thin clients” and wondered what they were talking about.

Firstly - no – chances are they aren’t doing a sideline in diet pills. Secondly, explaining the difference between a thin client and a thick client may be a little tricky. Rather than trying to explain the technical difference we thought we might try and explain the impact of each approach on an organisation.

To try and see the difference between a thin client and thick client imagine you needed to get a group of people from one place to another. If it was only a handful of people they might all have company motor cars, or they might share a company motor car. This works for small groups, but as the numbers start to get larger it becomes less and less practical (there isn’t enough parking at the destination, everyone needs to submit their fuel claims, a couple of people’s cars don’t work properly and need to be repaired before they can go, and some people also get lost on the way).

This is somewhat analogous to a “thick client” solution. Everyone has the utility and flexibility to go wherever they need to with only minor constraints (you need to travel on a road, follow the company vehicle use policy etc). The downside for the organisation is it needs to pay to maintain a whole fleet of cars, and substantial effort is spent keeping vehicles running properly.

Now consider an alternate approach. If everyone is going to approximately the same place every day (ie using the same applications) then maybe the organisation is better of with a bus. To move a large group of people there is less administration, parking problems, vehicle maintenance etc, and only the driver needs to know where the bus is going (so you only need to buy 1 GPS instead of 50).

The bus is more like a “thin client” or terminal solution. The people onboard have less freedom and flexibility, but provided they were all going that way anyway this may not be a big deal. Like the bus, a terminal solution requires certain equipment (a terminal server), which can be a substantial capital outlay relative to a few motor cars, but at some point, provided all staff are served well enough by the bus, it will be cheaper to run than the fleet of cars. The graph below illustrates this concept in terms of cost.

As you can see the terminal based approach has a higher set up cost but as the number of stations increases it is more cost effective. Now don’t worry about the exact numbers in this diagram – there are a whole lot of factors that influence this, but understanding this basic relationship is an important part of understanding the value of a terminal based approach.

The value proposition is as follows: If your requirements suit it, then the terminal server solution can deliver productive, reliable computing at a lower cost per station than using thick clients for all staff.

However, going back to our “bus” model can also help us see situations which terminal servers are not well suited to:

• Everyone is going to a different place – If everyone needs to run completely different applications then the terminal server may not be the right approach
• Everyone needs to attach different equipment – the bus can only have so many trailers attached to it. If everyone needs to use a PDA, or special data logger, or other peripheral then the bus may not be the right approach.
• Some Requirement’s Don’t Socialise Well – Just like the bus there is limited space and capacity on the terminal server before applications can start to seriously interfere with others ability to use the service. These “anti-social” requirements are probably better suited to stand alone thick clients.

You can also mix and match terminal and thick client deployments. For example, if 80% of you staff have “basic” needs you can have them use a thin client. The users with additional requirements can use a thick client for all the special tools they need, and use a software thin client to access the normal “corporate desktop” – they use the bus for the same things as everyone else, and only use their thick client for special jobs.

As you may have already surmised an important part of operating a successful terminal server installation is discipline. The organisation needs to be disciplined enough to protect the reliability of the terminal server by not letting unnecessary software be installed, and having the time and patience to set up user access so that staff can’t accidentally damage the server. This is one of the reasons that organisations with a mature outlook at Information Technology are the ones most likely to gain benefit from an investment in a terminal type approach.

While we have spoken quite a bit about restrictions it is important not to oversell these for a terminal solution. Staff that only need to use word, excel, email and a web based database or two can operate quite successfully on terminal solutions and never even know that they don’t have their own computer.

There are however, odd things that can catch you by surprise. A typical example is displaying video. As you probably know video is a rapid sequence of still pictures that our eyes interpret as motion. Due to the nature of the technology terminal solutions usually can’t send this stream of pictures fast enough to make a cohesive video – to fool our eyes into thinking it is watching real motion. Now that probably seems all right, until you realise that you were planning on rolling out video based training to your staff. New techniques may (and are) change this in the future, but it is an example of where the normal utility of a PC is not necessarily available for a thin client.

Another interesting issue that emerges with thin clients is printing. One advantage of thin clients is that they often work very well over skinny network connections. However, while the staff member’s experience when working on a document is good, due to the vagaries of drivers, printing can be a completely different issue. That innocent ten page document can blow out into hundreds of megabytes of information which takes minutes and minutes to download and print.

So before you make a decision to go to thin clients you should have a really clear idea of what your staff are going to be doing with their computer access. If you can’t be sure on their requirements, but you still think thin clients is the way to go you need to be mindful of the risks that such an approach entails. You may find a need down the track that thin clients can’t meet, and you will end up with some thick clients. However, if you have a clear understanding of what you will be using thin clients for, the opportunity to save some money can be substantial.