Why not replace the old centralized systems with distributed ones?
Old mission-critical application software can include thousands of custom features tailored to suit the needs of its owners. Any effort to reengineer or replace these old systems immediately runs into a problem. The original developers worked with an incomplete set of specifications, and many of the specifications they did create were lost. The system was the product of trial and error at meeting the requirements of an often-changing set of clients. They seldom understood the clients reasons for making the system function as it does. After decades of modifications and renovations internal complexity increased making application hard to maintain and difficult to test. Because knowledge of the functioning of the application is lacking or deficient, modification of non-compliant software can create more problems. An IT shop is not prepared to take on a conversion project which involves management complexity, tool requirements, higher staffing levels, and huge expenses. Maintenance tools a
