Process Scheduler Type Activity (i) Long Term Scheduler (P) executes much…
2023
| Process Scheduler Type |
| Activity |
(i) | Long Term Scheduler | (P) | executes much faster to reduce wastage of CPU time |
(ii) | Medium term scheduler | (Q) | controls degree of multi programming |
(iii) | Short Term scheduler | (R) | is associated with swapping |
with respect to Process Schedulers of an operating system mentioned above in the table, which of the following statements is correct?
- A.
(i) – (R), (ii) – (P), (iii) – (Q)
- B.
(i) – (Q), (ii) – (R), (iii) – (P)
- C.
(i) – (P), (ii) – (R), (iii) – (Q)
- D.
(i) – (R), (ii) – (Q), (iii) – (P)
Attempted by 407 students.
Show answer & explanation
Correct answer: B
Concept
An operating system uses three kinds of process schedulers, each defined by what it decides and how often it runs:
Long-Term Scheduler (job scheduler): admits jobs from the job pool into the ready queue, thereby fixing how many processes are in memory at once — i.e. it controls the degree of multiprogramming. It runs infrequently.
Medium-Term Scheduler: temporarily removes (swaps out) processes from memory to disk and later brings them back (swaps in), so it is the scheduler associated with swapping.
Short-Term Scheduler (CPU scheduler): picks the next ready process for the CPU; because it must run very often (milliseconds), it has to be fast so that CPU time is not wasted.
Applying it to the table
(i) Long-Term Scheduler → controls degree of multiprogramming = (Q).
(ii) Medium-Term Scheduler → is associated with swapping = (R).
(iii) Short-Term Scheduler → executes much faster to reduce wastage of CPU time = (P).
Cross-check
The defining property of each scheduler maps to exactly one activity with no overlap: admission/multiprogramming is unique to the long-term scheduler, swapping is unique to the medium-term scheduler, and high-frequency fast dispatch is unique to the short-term scheduler. Hence the consistent matching is (i)–(Q), (ii)–(R), (iii)–(P).