<Li> While the process is "waiting", it waits for the scheduler to do a so - called context switch and load the process into the processor . The process state then becomes "running", and the processor executes the process instructions . </Li> <Li> If a process needs to wait for a resource (wait for user input or file to open, for example), it is assigned the "blocked" state . The process state is changed back to "waiting" when the process no longer needs to wait (in a blocked state). </Li> <Li> Once the process finishes execution, or is terminated by the operating system, it is no longer needed . The process is removed instantly or is moved to the "terminated" state . When removed, it just waits to be removed from main memory . </Li> <P> When processes communicate with each other it is called "Inter-process communication" (IPC). Processes frequently need to communicate, for instance in a shell pipeline, the output of the first process need to pass to the second one, and so on to the other process . It is preferred in a well - structured way not using interrupts . </P>

The first active step in the memory process