They’re bulky, cumbersome, and outdated. They aren’t the fastest systems by a long stretch. And they sometimes make strange noises. Yet, if upgraded for the future, they can provide a cost and time savings for many large businesses and government agencies.

Legacy mainframe computer systems, still in place at many large corporations, utility companies and government offices, may seem like relics from another era which should be discarded and replaced with the latest technology. But a recent study by two DePaul professors shows these systems can be retrofitted with the latest Web-based technology for a fraction of the cost of replacement using new technologies.

Using an application processing integrator, which allows programmers to convert older systems into optimized Web-enabled systems, the researchers found that it reduced programming time by more than 82 percent and cut programmer expense by more than 84 percent when compared with a full system rewrite using the Java programming language. The study was presented recently at the COBOLWorld 2002 Conference. This work is a continuation of research into productivity and costs associated with legacy system maintenance presented by the DePaul researchers at the Institute of Electrical and Electronics Engineers’ (IEEE) International Conference on Software Maintenance in Oxford, England.

"I liken the process to preserving a historic building," said Tom Muscarello, assistant professor of computer science at DePaul’s School of Computer Science, Telecommunications and Information Systems (CTI) and one of the study’s co-authors. "If the building can still be utilized, you don’t tear it down, you rehab it and make it suitable for modern use."

Muscarello estimates that there are more than 40,000 legacy servers in operation today, many of which date back to the 1970s and use the decades-old COBOL computer language. In fact, over 70 percent of business data in use worldwide (by some 25,000,000 users) resides in these legacy systems. The systems are often used by large corporations and government agencies for functions such as payroll, inventory, human resources and sales. Due to a legacy system’s size, it is not replaced with new platforms – such as Java – cheaply. With the economy making technology expenditures more difficult, replacing a legacy system completely becomes cost prohibitive and upgrading the systems becomes a more appealing option.

So, how important is this issue to the business and technology communities? A recent Gartner Group survey of IT executives and managers reveals that legacy integration is the top industry concern, being mentioned by almost half of the respondents.

"Companies today want to get more out of the resources they have," said Howard Kanter, an associate professor at DePaul’s School of Accountancy and Management Information Systems and a co-author of the study. "The more they can do without expensive consultants, the better. They want to find ways to keep 40-year-old payroll systems running and useful."

Muscarello said that use of the application processing integrator is a method to help modernize systems without blowing out a company’s budget.

"This is a way to use your resources to move forward, without spending millions of dollars," he said, noting the study has generated a buzz in the IT industry and a feature in a recent issue of Enterprise Systems Journal.

DePaul CTI is the one of the largest computer science programs in the country. The undergraduate program enrolls nearly 1,800 students and offers six different degrees. More than 2,400 students are enrolled in the graduate program, which offers nine different master’s degrees. DePaul CTI also features a Ph.D. program in computer science.

DePaul’s College of Commerce encompasses the university’s undergraduate business program, with more than 3,700 students, and the Kellstadt Graduate School of Business, which enrolls nearly 2,500 students. The college is among the top ten largest business schools in the United States. The school’s part-time MBA program is ranked fourth in the country by U.S. News & World Report.

DePaul is the largest Catholic university in the nation and eighth-largest private university in the United States. A richly diverse population of 23,227 students attends classes on two city and six suburban campuses.