Simulate and visualize various CPU scheduling algorithms like FCFS, SJF, and Round
Robin. Add processes with arrival times and burst times to generate a Gantt chart and calculate average waiting
and turnaround times.
Try:
Processes0
processes
PID
Arrival
Burst
Priority
Algorithm
Time Quantum (Round Robin)
Priority Order
Add processes and click ▶ Run to visualize scheduling
Gantt Chart
Summary
Per-Process Statistics
PID
Arrival
Burst
Start
Finish
Waiting
Turnaround
Response
Waiting vs Turnaround Time
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FCFS
First Come First Serve — processes run in order of arrival. Simple, but long processes
can block short ones (convoy effect).
SJF (Non-preemptive)
Shortest Job First — picks the shortest available job when CPU is free. Minimizes
average waiting time but can starve long processes.
SRTF
Shortest Remaining Time First — preemptive SJF. If a new process arrives with less
remaining time than the current, it preempts it.
Round Robin
Each process gets a fixed time quantum. Fair for interactive systems — set the quantum
in the controls. Smaller quantum = more context switches.
Priority (NP / P)
Schedules by priority number. Non-preemptive waits for current process to finish;
preemptive can interrupt if higher priority arrives.
HRRN
Highest Response Ratio Next — non-preemptive. Response ratio = (waiting + burst) /
burst. Balances SJF favoritism against starvation.
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How to use
Open the tool and enter your data or select options.
Adjust settings to see real-time updates.
Copy the generated result to your clipboard.
Frequently Asked Questions
What is CPU scheduling?
CPU
scheduling is a process that allows one process to use the CPU while the execution of another process is on hold
due to unavailability of any resource, making full use of the CPU.
What algorithms are supported?
This
tool supports First Come First Serve (FCFS), Shortest Job First (SJF), Shortest Remaining Time First (SRTF),
Round Robin (RR), Priority (Preemptive & Non-preemptive), and Highest Response Ratio Next (HRRN).
What is a Gantt chart?
A
Gantt chart is a type of bar chart that illustrates a project schedule. In this context, it shows exactly which
process is executing at any given time unit.
Did you know?
Round Robin scheduling was originally used in mechanical fairground carousels before being adapted for
computing.
The Shortest Job First algorithm is provably optimal for minimizing average waiting time.
Modern operating systems use complex multi-level feedback queue scheduling, which combines several of these
basic algorithms.