Process states (new, ready, running, waiting, terminated) in Operating Systems - Step-by-Step Execution

Concept Flow - Process states (new, ready, running, waiting, terminated)

New

↓

Ready

↓

Running

↓

Waiting

A process starts as New, moves to Ready when prepared to run, then Running when executing. It may go to Waiting if it needs resources, then back to Ready. Finally, it reaches Terminated when finished.

Execution Sample

Operating Systems

1. Create process -> New
2. Scheduler picks -> Ready to Running
3. Needs I/O -> Running to Waiting
4. I/O done -> Waiting to Ready
5. Process ends -> Running to Terminated

This sequence shows how a process moves through states during its life cycle.

Analysis Table

Step	Current State	Event/Condition	Next State	Explanation
1	None	Process created	New	Process is created but not ready to run
2	New	Initialization complete	Ready	Process is ready to run, waiting for CPU
3	Ready	CPU scheduler selects process	Running	Process starts executing on CPU
4	Running	Needs I/O or resource	Waiting	Process waits for I/O or event
5	Waiting	I/O or event completed	Ready	Process ready again for CPU
6	Ready	CPU scheduler selects process	Running	Process resumes execution
7	Running	Process finishes execution	Terminated	Process ends and is cleaned up

💡 Process reaches Terminated state, ending its lifecycle

State Tracker

Process State	Start	After Step 2	After Step 3	After Step 4	After Step 5	After Step 6	Final
State	None	Ready	Running	Waiting	Ready	Running	Terminated

Key Insights - 3 Insights

Why does a process move from Running to Waiting?

Because it needs to wait for an event like I/O completion, as shown in step 4 of the execution_table.

Can a process go directly from New to Running?

No, it must first become Ready after initialization (step 2), then the scheduler moves it to Running (step 3).

What happens after a process reaches Terminated?

The process is cleaned up and removed from the system; it cannot move to any other state (step 7).

Visual Quiz - 3 Questions

Look at the execution_table, what is the process state after step 4?

A Running

B Waiting

C Ready

D Terminated

💡 Hint

Check the 'Next State' column for step 4 in the execution_table.

At which step does the process first enter the Ready state?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Look at the 'Next State' column and find when 'Ready' appears first.

If the process never needs I/O, which state will it skip according to the execution_table?

A Waiting

B Ready

C New

D Terminated

💡 Hint

Check which state is entered only when the process needs to wait for I/O (step 4).

Concept Snapshot

Process states:
- New: Created but not ready
- Ready: Waiting for CPU
- Running: Executing on CPU
- Waiting: Paused for I/O or event
- Terminated: Finished and cleaned up
Processes cycle through these states during execution.

Full Transcript

A process starts in the New state when created. After initialization, it moves to Ready, waiting for CPU time. When the scheduler picks it, it moves to Running and executes. If it needs to wait for I/O or other events, it moves to Waiting. Once the event completes, it returns to Ready. Finally, when the process finishes, it moves to Terminated and is removed from the system. This cycle ensures efficient CPU use and resource management.