Special Feature A Survey of Methods of Achieving Reliable Software

As organizations become more dependent on computers, they become more sensitive to computer system failures. The importance of computer reliability in realtime control systems (e.g., communications systems^8,15and traffic control systems) has been recognized for some time. Many computer users are now becoming aware that they accomplish more on systems which seldom crash because of malfunctions than on systems which run very rapidly (and correctly) between frequent crashes. Consequently, increasing emphasis is being placed by users and vendors on the reliability of the total system, and particularly the system software. A notable example of this is the emphasis placed by IBM on reliability concerns in the design and implementation of OS/VS2 Release 2.^35,36