Operations on Process | Process creation | Process preempting

1. Process creation:  A user requests, and already running process can creates new processes. Parent process creates children processes using a system call, which, in turn create other processes, forming a tree of processes.
2. Process preempting:  A process preempted if I/O event or timeout occurs. Then process moves from running state to ready state and CPU loads another process from ready state to running state, if available.
3. Process blocking: When a process needs I/O event during its execution, then process moves from running state to waiting state and dispatches another process to CPU.
4. Process termination:  A process terminated if when a process completes its execution. Also, these events: OS, Hardware interrupt, and Software interrupt can cause termination of a process.