The useful life of pre-relational mainframe database management system engines is coming to an end because of a diminishing application and skills base, and increasing costs. — Gartner Group
During the last 30 years, many companies have deployed mission critical applications running various aspects of their business on the legacy systems. Most of these environments have been built around a proprietary database management system running on the mainframe. According to Gartner Group, the installed base of mainframe, Sybase, and some open source databases has been shrinking. There is vendor sponsored market research that shows mainframe database management systems are growing, which, according to Gartner, is due primarily to increased prices from the vendors, currency conversions, and mainframe CPU replacements.
Over the last few years, many companies have been migrating mission critical applications off the mainframe onto open standard Relational Database Management Systems (RDBMS) such as Oracle for the following reasons:
Reducing skill base: Students and new entrants to the job market are being trained on RDBMS like Oracle and not on the legacy database management systems. Legacy personnel are retiring, and those that are not are moving into expensive consulting positions to arbitrage the demand.
Lack of flexibility to meet business requirements: The world of business is constantly changing and new business requirements like compliance and outsourcing require application changes. Changing the behavior, structure, access, interface or size of old databases is very hard and often not possible, limiting the ability of the IT department to meet the needs of the business. Most applications on the aging platforms are 10 to 30 years old and are long past their original usable lifetime.
Lack of Independent Software Vendor (ISV) applications: With most ISVs focusing on the larger market, it is very difficult to find applications, infrastructure, and tools for legacy platforms. This requires every application to be custom coded on the closed environment by scarce in-house experts or by expensive outside consultants.
Total Cost of Ownership (TCO): As the user base for proprietary systems decreases, hardware, spare parts, and vendor support costs have been increasing. Adding to this are the high costs of changing legacy applications, paid either as consulting fees for a replacement for diminishing numbers of mainframe trained experts or increased salaries for existing personnel. All leading to a very high TCO which doesn't even take into account the opportunity cost to the business of having inflexible systems.