Degree of multiprogramming is controlled by?

Answer: The long-term scheduler controls the degree of multiprogramming by deciding which processes are admitted into memory.

What degree of multiprogramming means: It is the number of processes kept in main memory at the same time. A higher degree means more processes are resident concurrently.

• Role of the long-term scheduler: Also called the admission scheduler, it selects jobs from the job pool and admits them into memory for execution. By controlling admissions, it directly sets the degree of multiprogramming.

• Role of the medium-term scheduler: It can influence the degree by swapping processes out of memory to reduce load or swapping them back in, but it does not perform the initial admission decision.

• Role of the CPU (short-term) scheduler: It decides which ready process runs on the CPU next; it manages CPU allocation, not admission into memory.

Summary: The long-term scheduler is the primary controller of the degree of multiprogramming because it admits processes into memory; the medium-term scheduler can adjust the resident set by swapping, and the CPU scheduler handles CPU allocation.