A rendezvous with multitasking multiprocessors

Controlling process plants using computers has always had spectacular failures as well as successes. A modern distributed control system (DCS) is very powerful, incorporating multitasking multiprocessors. However, unless this power is controlled, severe technical difficulties frequently arise, causing over spending and lateness. Multitasking and multiprocessing environments allow a number of application programmes to be active simultaneously. Academics have identified and analysed the problems of interfacing application programmes operating in these environments. A number of standard solutions, which co-ordinate both the information exchange and operation of the programmes, are now widely accepted. Unfortunately these have not yet been incorporated into distributed control systems, instead only limited lower level facilities are provided. However, the application programmer can implement these solutions using what facilities are provided. The author explains how this may be achieved and outlines the benefits of doing so