Multiprocessors and Multicomputers

There are computers wth just one processor. Large computer systems may contain a number of processor units, in which case they are called multiprocessor systems. These systems either execute a number of different application tasks in parallel. or they execute subtasks of a large single task in parallel. All processors usually have access to all the memory in such systems, and the term shared memory multiprocessor systems is often used to make this clear. The high performance of these systems comes with much increased complexity and cost. In addition to multiprocessors and memory units, cost is increased because of the need for more complex interconnection networks. In contrast to multiprocessor systems it is also possible to use an interconnected group of complete computers to achieve high total computational power. he computer normally have access only to their own memory units. When the task they are executing need to communicate data, they do so by exchanging messages over a communication network.