The Metamorphosis of the Mainframe Computer: The Superserver

Mainframe computers, which once dominated the computer hardware and software markets, have become increasingly unpopular with users. Major mainframe manufacturers have felt this decline in user demand. In 1994 mainframe computers amounted to only about 30 percent of IBM\u27s total computer sales, compared with 90 percent in 1984. UnisysCorporation announced in 1994 that it would entirely discontinue manufacturing its line of mainframe computers, electing to concentrate on more profitable areas of the computer market. Despite a trend where users abandon mainframe solutions, computer processing demand by business, industry, government, and private users is growing at a geometric rate. Unfortunately, the growing demand for computer services has been imperfectly sustained by smaller-scale but more user-friendly computers, especially networks of personal computers. However, evidence suggests that the decline of the mainframe computer will soon end. Based on this information, we believe that the mainframe will reemerge to prominence. However, it will do so in a transformed state--as a superserver. In its metamorphosis, the superserver will replace the general purpose processor as a multi-purpose processor which will perform a broad spectrum of functions, including functions of the legacy system, the database server, and the windows serve

Abstractions for Fault-Tolerant Distributed System Verification

Four kinds of abstraction for the design and analysis of fault tolerant distributed systems are discussed. These abstractions concern system messages, faults, fault masking voting, and communication. The abstractions are formalized in higher order logic, and are intended to facilitate specifying and verifying such systems in higher order theorem provers