"I don't think it's an overstatement to say the mainframe has been the engine that has driven the business-computing evolution," says Charles King, an analyst at the Sageza Group, a technology research and consulting firm. "They set the table for what has resonated for a long time."
Bill Zeitler, current senior VP and group executive of the Operating Systems and Technology group at IBM, says the 360 "was a once-in-a-generation kind of statement. But if the mainframe only did today what the original system did, or its successors did, it would be dead already."
The mainframe has been able to stay a vital part of IBM and the IT industry because it has evolved and expanded its capability to include new technology platforms such as Linux, Java, and WebSphere, Zeitler says. While the 360 series defined the mainframe class of computers with its ability to support multiple users and the compatibility and scalability to meet customer requirements, today's mainframe is defined as a high-end computing environment that uses virtualization to support multiple operating environments, he says.
Rivals have been trying kill off the IBM mainframe for decades. For two years, Sun Microsystems has been offering a "rehosting" program that moves companies off mainframes to its Sun Fire servers; to date, Sun has worked with about 300 companies, says Don Whitehead, director of mainframe migration for Sun. "The mainframe has been a huge success story in the marketplace," he says. "A 40-year run for any technology is just tremendous. But we think maybe the mainframe should start thinking about a retirement strategy."
IBM believes the mainframe isn't ready for the rocking chair. The most recent addition to the five decades of IBM mainframes, introduced last year, is the Z990, code-named TRex. "Some of our competitors were saying the mainframe was a dinosaur, so we gave the new systems code-names of carnivorous dinosaurs," Zeitler says. "If you think we're a dinosaur, you're going to be rudely surprised."