Difference Between Long-Term and Short-Term Scheduler in OS

In this post, we will understand the difference between long-term and short-term schedulers in operating system −

Long-term scheduler

• It is also known as the job scheduler.

• This scheduler takes the process from the ‘job pool’.

• In this scheduler, the programs are setup in the queue.

• Based on the requirement in hand, the relevant job is selected.

• It regulates more DOM (Degree of Multi-programming).

• It regulates the programs that are selected by the system to be processed.

• It has less speed in comparison to the short-term scheduler.

• It changes the state of the process from ‘New’ to ‘Ready’.

• This kind of scheduler is not used by time-sharing operating systems.

• It selects a relevant process, the right mix of I/O bound and CPU bound.

Short-term scheduler

• It is also known as CPU Scheduler.

• This scheduler takes the process from ‘ready’ queue.

• No queue exists in this scheduler.

• It regulates less DOM (Degree of Multi-programming).

• It ensures the right program that is important/required to be processed.

• It has a high speed in comparison to the long-term scheduler.

• It changes the state of the process from ‘Ready’ to ‘Running’.

• It may be used minimally in a time-sharing system.

• It selects a new process for the CPU frequently.