When an Operating system process executes, Process may change its state. Process may be in one of the following state:
As soon as a new process is created, process is in the initial state.
Process is waiting to be assigned CPU time. Operating system allocates the processor time to the ready process. Process can come into this state either after the new state or when interruption occured during the running state of the process.
Once the process gets the CPU time, process instructions are being executed. Only one process is running on any processor at any instant.
Running process needs some resources or some events to occur (such as I/O complete, waiting for user input and waiting for input file). The process waiting for user input, input file or another event is said to be in waiting state.
the process has finished execution