What is an application server?

What is an application server? Since silicon.com launched its latest Hot Topic on the subject, we've heard a range of definitions.

One reader told us: "Ask 10 different people and get 10 different answers."

In terms of definitions, that isn't strictly true. We have one analyst from Ovum on tape neatly defining the phrase (see: http://www.silicon.com/a53861 ): "[An application server is] the runtime infrastructure in services necessary for running applications in a multi-client environment."

The trouble is, such a summing up doesn't do a lot of non-technical users - and even some technical users - much good. That's why we did the rest of that interview.

Instead, think of the 10 different answers to the question 'what is an app server?' as meaning the 10 things people most often associate with the technology or the top 10 misconceptions.

An app server is at its base level nothing more than dedicated software that sits on a central computer which makes different applications available to users, sometimes internally in an organisation, sometimes over the internet. And if all the applications you use sit on your PC's C drive, then lucky you - or unlucky you, as the case may be.

App servers enable payroll systems, supply chain management systems, publishing systems (as we know well at silicon.com) and more. In fact, in around 94 per cent of instances app servers are used for custom designed applications, according to AMR Research.

Application servers are:
- increasingly big business - a market worth billions with users charged per server processor (up to around £25,000/proc)
- essential - by 2003 at least 70 per cent of new applications will be deployed on high-end app servers, Gartner says
- at the heart of web services (see: http://www.silicon.com/ws for more)

Application servers are NOT:
- application services or application service providers (remember ASPs?)
- hardware - don't be put off by the word server
- something most of us need to understand up close - though we should all know why they're important.

The last point illustrates why we're writing this. If you have a question on the subject or a better definition, please add a Reader Comment below. Over-simplification only helps those people in the know, which isn't healthy. Take away one last figure: companies have spent $1bn too much on app servers since 1998 - ignorance isn't always bliss.

For our full take on the rise of application servers, see our Hot Topic: http://www.silicon.com/appservers