Computer technology, particularly at the circuit level, is fast
approaching its physical limitations. As future needs for greater
power from computing systems grows, increases in circuit switching
speed (and thus instruction speed) will be unable to match these
Greater power can also be obtained by incorporating several processing
units into a single system. This ability to increase the performance
of a system by the addition of processing units is one of the major
advantages of multiprocessor systems. Four major characteristics of
multiprocessor systems have been identified (28) which demonstrate
their advantage. These are:-
The additional throughput obtained from a multiprocessor has been
mentioned above.. This increase in the power of the system can be
obtained in a modular fashion with extra processors being added as
greater processing needs arise. The addition of extra processors
also has (in general) the desirable advantage of giving a smoother
cost - performance curve ( 63). Flexibility is obtained from the
increased ability to construct a system matching the user 'requirements
at a given time without placing restrictions upon future expansion.
With multiprocessor systems; the potential also exists of making
greater use of the resources within the system.
Availability and reliability are inter-related. Increased availability
is achieved, in a well designed system, by ensuring that processing
capabilities can be provided to the user even if one (or more) of the
processing units has failed. The service provided, however, will
probably be degraded due to the reduction in processing capacity.
Increased reliability is obtained by the ability of the processing
units to compensate for the failure of one of their number. This
recovery may involve complex software checks and a consequent decrease
in available power even when all the units are functioning.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.