IF THE group that Thomas Kurian runs was an independent software company, it would be the eighth-largest and the fastest-growing company of its size in the world.

But because the group is part of US-based software giant Oracle, a company better known for making database and business application software, this fact is largely unrecognised.

Mr Kurian is the senior vice-president of Oracle's server technologies development division, which is charged with developing "middleware" software to link various applications a company might run to improve the way they work together.

Since Oracle's middleware group was formed in 2001, the division has advanced from nothing to $US1 billion ($A1.22 billion) in revenue, and is growing at a rate of 60 per cent this year.

"If you counted Oracle Middleware as a stand-alone company, there are only seven software companies in the world that are larger," Mr Kurian says. "And no one is growing at 60 per cent."

While middleware is considered to be very much at the un-sexy end of the computing scale, Mr Kurian's group is playing a vital role in helping to link the various applications Oracle now owns as a result of its acquisitions of rival software makers PeopleSoft, J. D. Edwards, Siebel Systems and Hyperion, as well as its own Oracle eBusiness suite.

It also underpins the development of Oracle's next-generation software application suite, which is supposed to bring them altogether into one application suite, called Oracle Fusion.

Mr Kurian says the key to Oracle's middleware success has been its dedication to a software development concept known as service-oriented architecture (SOA), whereby a system's various components are designed to be easily interoperable.

Each software component acts as a "service", such as a ticket booking service or filling out an online application, with definitions built into the software to describe how the components interact.

"We wanted to offer a standards-based technology foundation to allow customers to build their own applications, as well as to integrate other systems," Mr Kurian says. "It's much more flexible to meet the needs of the business, it's much lower-cost to own and operate, and it's much more easily customisable and upgradeable. This reduces the cost and time for you to do the integration."

Despite its heritage in databases and business applications, Oracle has emerged as a strong middleware vendor in its own right. Mr Kurian says there are 35,000 customers worldwide who use the middleware software without also using Oracle's applications suites, and Oracle is adding 5500 new customers each year, compared to its competitors, who added fewer than 1000. About 23 per cent of its middleware customers are using no other Oracle products.

By using SOA middleware as the glue to bind software from its various acquisitions, Mr Kurian says, Oracle has been able to extend the time it will be able to support such applications, from the original estimate of 2013 to beyond 2017. He acknowledges, however, that by extending both the lifespan of such applications Oracle is providing less motivation for customers to upgrade to the Fusion application suite.

"We're not forcing anyone to move to Fusion," Mr Kurian says. "If you are a PeopleSoft customer and you are happy to stay on PeopleSoft for perpetuity, we are going to continue building out PeopleSoft, eBusiness Suite, J. D. Edwards or Siebel."

Mr Kurian says Oracle is keen to ensure the features of Oracle Fusion match those of its various existing applications. But, he says, the real advantage will come from Fusion having been built from the ground up using SOA principles, allowing the business to customise a process simply by changing the way it is defined.

About 45 per cent of Oracle's middleware business comes through partner organisations, including 5000 software developers, one of which is the Melbourne-based software developer Emersion. Managing director Paul Dundas says Emersion has built an SOA-based telecommunications billing system based on Oracle's middleware, which has been particularly useful in buildings links to the software used by telecommunications carriers.

"We were going to develop with some open-source software, but we discovered that while it was very good as an engine, the interface was abysmal," Mr Dundas says.

"We ended up going to Oracle, when it became evident to us that the return on investment was going to be short in terms of man hours. The interface that Oracle provided was very easy to use for the developer guys, and we have had zero external training on it."