Getting parallelism into perspective

Parallelism raises many novel issues not present in sequential computing, as well as new twists to older issues. How is the ordinary user to come to terms with exploiting parallelism for applications? It is argued that, by developing and characterising the concept of an abstract programming model based on a virtual architecture, a clearer perspective is achieved. Two examples of virtual architecture are outlined: (virtual memory extensions) of a shared variable model and of a message passing model