LIST-I LIST-II A. Short term scheduler I. Determine which process are added to the system for execution level place them in ready queue. B. Medium term scheduler II. Select which process should be executed next and allocate CPU time. C. Long term scheduler III. Manage the degree of multi programming by swapping processes between main memory and disk storage D. I/O Scheduler IV. Order the input/output requests from processes waiting for I/O operations.
Operating System Schedulers Matching
This solution explains the matching of different operating system scheduler types (LIST-I) with their specific functions (LIST-II).
Scheduler Functions Explained
Understanding the role of each scheduler is crucial for process management:
- Short Term Scheduler (CPU Scheduler): Its primary function is to quickly select a process from the ready queue and allocate the CPU to it for execution.
- Medium Term Scheduler: This scheduler manages the degree of multiprogramming. It removes processes from memory (swaps out) to reduce the number of active processes and loads them back later (swaps in).
- Long Term Scheduler (Job Scheduler): Responsible for selecting processes from the job pool (or input queue) and admitting them into the system for execution, thereby controlling the overall degree of multiprogramming.
- I/O Scheduler: Manages the various I/O requests from processes, deciding the order in which these requests should be serviced by the I/O devices.
Matching Schedulers with Functions
Based on these functions, we match the items:
- A. Short term scheduler matches with II. Select which process should be executed next and allocate CPU time.
- B. Medium term scheduler matches with III. Manage the degree of multi programming by swapping processes between main memory and disk storage.
- C. Long term scheduler matches with I. Determine which process are added to the system for execution level place them in ready queue.
- D. I/O Scheduler matches with IV. Order the input/output requests from processes waiting for I/O operations.
Final Scheduler-Function Pairing
The correct matching is therefore A-II, B-III, C-I, D-IV.
| LIST-I Item | LIST-II Description |
| A. Short term scheduler | II. Select process for next execution & allocate CPU |
| B. Medium term scheduler | III. Manage multiprogramming degree via swapping |
| C. Long term scheduler | I. Select processes to add to the ready queue |
| D. I/O Scheduler | IV. Order I/O requests |
This combination corresponds to the correct answer.
Important Questions from Process Scheduling
Which of the following queues keeps a set of all processes residing in main memory ready and waiting to execute?
An OS follows round-robin scheduling with time quantum of 4ms. Assuming that the CPU is free now and there are 20 processes waiting in the ready queue, the maximum amount of time that a process waits before getting into the CPU is _________.
