A computer program itself is just a passive collection of instructions, while a process is the actual execution of those instructions.
Several processes may be associated with the same program; for example, opening up several windows of the same program often means more than one process is being executed. In the computing world, processes are formally defined by the operating systems (OS) running them and so may differ in detail from one OS to another; for example in Microsoft Windows environment each instance of the same application is called a task.
- Knott 1974, p.8
- Gary D. Knott (1974) A proposal for certain process management and intercommunication primitives ACM SIGOPS Operating Systems Review. Volume 8 , Issue 4 (October 1974). pp. 7 - 44