The Process passes from different states, from its formation to completion.
The following are the states of the Process.
- Block or Wait
- Terminated or Completed
- Suspend ready
- Suspend wait or suspend blocked
- New: – The state in which a process is created. The New state is the newly created program which is stored in the secondary storage, and taken by the operating system at the time of process creation.
- Ready: – After a process has been created, it enters into the ready state means the process is loaded into the memory. In this, the process is set to run and wait for its execution time to get the CPU. Processes that are ready for CPU execution are placed in a queue for a ready process.
- Run: – In a run state, the CPU selects the process for execution and executes the instructions within the process.
- Blocked or Wait: – If the process is in run state and the process needs some resources for execution, but the resource is held by some other process than the process enters into the blocked or waiting state.
- Terminated or Completed: – If the execution of the process is completed, then the process enters into the terminated or completed state.
- Suspend ready: – Sometimes, due to the minimum number of resources, some process which is in ready state transfer or moves to secondary storage from the primary storage, and this type of process that move in the ready state are called suspend ready.
- Suspend wait or suspend blocked: – Suspend-wait is like suspend blocked and uses the process which is performing input/output operation and due to minimum amount of main memory move them into secondary storage. It may go to suspend ready when work is finished.
Operations on the Process
There are various operations which are performed on the Process:
Creation: – If the process is created, then it will be ready to enter the ready queue and ready to run.
Scheduling: – There are so many processes which are present in the ready queue, the operating system selects one process from various processes and start to execute the process. The selection of process in a sequence for execution is called scheduling.
Execution: -After the scheduling is done on the process then the process starts executing. Sometimes there may be a situation that arises when the process enters into a blocked or wait state during the execution, then in such a case, the processor starts to execute another process.
Deletion/Killing: – When the objective of the process completes, the operating system kills the process. The process control block of the process is also deleted, and the operating system terminates the process.