Revenge of the monolith

There is a certain deja vu afoot today as managers review their software portfolios. The problem goes back a few years. "People thought they were going to throw their mainframes away," said Dale Vecchio at Gartner's recent AD Summit in Los Angeles. "That didn't happen." Vecchio is research director at Gartner Inc.

Vecchio and others note that XML-based Web services have become something of an unexpected bit of good fortune for mainframers. Touted as the next "cool thing," Web services have as often as not proved to be an update mechanism for the first cool thing - the mainframe.

But "exposing legacy is tough. Mainframe CICS-class apps are monolithic," he said.

Wrappering apps with XML veneers may work for now, but mainframe apps aren't yet truly playing in the distributed Web space. Dev teams will find new challenges, said Vecchio, as they find their mainframe apps "have to be dismembered into Web services."

Moreover, "the transactions have to be fast," he noted. This is the great strength of the mainframe, but is not the strong suit of Web services.

The deeper you go in, said Vecchio, the more it resembles a Y2K problem. Long-running code has to be understood even though the original code developers have left. The challenge for the mainframer is to "open up the Pandora's Box," he said.

Today, app development managers that search for order in legacy systems embrace some added risk. As with Y2K projects, the tools for portfolio scanning can be very specialized and proprietary. This has led to the creation of nascent standards bodies such as the Legacy Transformation Working Group, which was recently chartered by the OMG to standardize aspects of legacy transformations from proprietary platforms into the Model Driven Architecture (MDA).

Vecchio is not ready to predict the success of MDA here, however. "It is very, very early. I think it's really ambitious. Anyone who does legacy knows it's a snake pit."

For more, please read "It's the mainframe's turn to get the services treatment" by Deborah Melewski.

About the Author

Jack Vaughan is former Editor-at-Large at Application Development Trends magazine.


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