Enterprises support $4.5 trillion worth of legacy systems: estimate

There's gold in those legacy systems running in the back rooms. You just need to know where to dig.

Such systems -- presumably mainframes and midrange-class systems such as IBM System i and high-end Unix boxes -- still have plenty to offer enterprises. It's a matter of both developing methodologies that open up these systems, as well as cutting down number of applications supported.

That's the view of Kristof Kloeckner, general manager of IBM Rational Software, who was recently interviewed in IBM's own magazine. Using the proper tools, techniques and collaborative teamwork, IT can combine existing code and knowledge with newer techniques and technology to speed delivery of new services, he advocates.

Of course, IBM has a major horse in this race -- many of the world's "legacy" systems are IBM boxes, after all. But there's a lot to be said for opening up these systems to new ways of computing, versus the more expensive rip and replace. Kloeckner estimates there is at least "a $4.5 trillion cumulative investment" in software from 1995 to 2010 alone.

As it stands, he says, this massive base of legacy -- which requires considerable upkeep -- holds back progress:

"Sadly, 70 to 80% of the development effort taking place within mature enterprises is actually spent on maintaining existing systems. This preoccupation with 'keeping the lights on' prevents them from reacting to new challenges and opportunities in an agile fashion."

That's why working closely with the business -- and helping business decision makers understand what kind of computing power and assets already exist somewhere in the enterprise -- is key, Kloeckner says.  Develop a way both IT and the business can look at its entire IT portfolio, and work together to winnow down all those applications to the vital few that support essential functions. Of course, he recommends IBM solutions to help accomplish this, but there are a range of vendor tools and platforms that can help manage application lifecycles, replatform applications, and virtualize and consolidate IT assets. Importantly, by winnowing down applications to the percentage that actually support most of the business, IT and business managers will be able to better focus on business priorities on hand.

Of course, there's $4.5 billion worth of systems and applications to sort through.