"While many aging systems remain inflexible and are disproportionately expensive to maintain, (and may be impossible to modify), they may not be the priority for replacement if they are not constraining current business strategies and processes," Prentice said.

"Newly installed systems, while utilizing up-to-date technology, may not be delivering services in line with changed business strategies and will be constraining [business] and must be regarded as 'legacy'."

While he says legacy systems impede business progress, Gartner emphasizes that legacy thinking should be the catalyst for improvement.

"The primary issue is not hardware or software, but individual and corporate attitudes towards change. Skills will change and older staff will struggle ... we anticipate significant changes in the skills required in IT in the future [by 2010], as the emphasis moves away from pure technology towards a focus on business, process, information and relationship management," he said.

Gartner analyst Brian Gammage said the goal is to replace a legacy business with a real-time enterprise, which detects and responds to opportunities and problems faster. The company must then implement real time IT infrastructure (RTI), which is more automated and less heterogeneous.