As fast and powerful commodity processors have been developed, it has
become practical to emulate the proprietary hardware systems of powerful
older computers on platforms built using commodity processors. The
systems being emulated are often large mainframe computers with large
numbers of disks, communications systems and other attached hardware.
Because of the size and expense, and also because databases involved must
reside in only one location, it is difficult to replicate these systems
for testing, development, debug or for providing alternative options to
customers. A method for providing a single emulated computer system which
provides for multiple views or options in control of the emulator is
disclosed in which the options are dependent and selected based on job or
user basis. The mechanism continues to provide for high performance and a
single copy of the operating system with multiple processes, jobs and
threads being emulated under user controlled parameters.