LONGEST JOB FIRST
L.J.F.
Basic Theory :
In LJF Scheduling,Out of all the available processes,
CPU is assigned to the process having largest burst time.In case
of a tie, it is broken by FCFS scheduling algorithm.
It is non-preemptive algorithm. This algorithm is based upon the burst time of the processes. The processes are put into the ready queue based on their burst times i.e., in a descending order of the burst times. As the name suggests this algorithm is based upon the fact that the process with the largest burst time is processed first. The burst time of only those processes is considered that have arrived in the system until that time.
It is non-preemptive algorithm. This algorithm is based upon the burst time of the processes. The processes are put into the ready queue based on their burst times i.e., in a descending order of the burst times. As the name suggests this algorithm is based upon the fact that the process with the largest burst time is processed first. The burst time of only those processes is considered that have arrived in the system until that time.
- First, sort the processes in increasing order of their Arrival Time.
- Choose the process having highest Burst Time among all the processes that have arrived till that time. Then process it for its burst time. Check if any other process arrives until this process completes execution.
- Repeat the above both steps until all the processes are executed.