IBPS SO IT Officer Operating System Important Questions 2026 is a focused set of 15 high-yield OS questions built around the concepts that repeat most often in the Professional Knowledge paper — CPU scheduling, synchronization, deadlock, memory management, virtual memory, and file systems.
Operating Systems is one of the highest-weightage subjects in the IBPS SO IT Officer Professional Knowledge section, right alongside DBMS and Computer Networks. Yet most OS study material online is written for general software-engineering interviews, not for the scenario-based, calculation-style MCQs that IBPS actually asks. This guide closes that gap — 15 exam-style questions with full explanations and quick revision notes you can run through the night before your Mains exam.
With IBPS SO Mains 2026 scheduled for 1 November, this is the exact window to lock down your OS fundamentals. Use this list as a revision checkpoint, then move into timed topic-wise practice.
Revising All Subjects? Start With the Complete Question Set
This article goes deep on Operating Systems. If you want a broader Professional Knowledge sweep across DBMS, Networks, OS, DSA, and Cybersecurity, start with our complete 15 Most Expected Questions guide.
15 Important IBPS SO IT Officer Operating System Questions
Each question below targets a concept examiners test repeatedly — some as pure definitions, others as short scenarios you need to reason through. Cover the answer, attempt it yourself, then check your logic against the explanation.
Process & Thread Basics (Questions 1–2)
Before scheduling and synchronization make sense, you need to be clear on what a process actually is and the states it moves through.
Which of the following is NOT one of the standard process states in a typical process state transition model?
A process is moved from the Running state back to the Ready state without completing its CPU burst. Which event most likely caused this transition?
CPU Scheduling (Questions 3–5)
Scheduling questions can be purely conceptual or ask you to trace through a small Gantt chart. Make sure you're comfortable with both.
Which CPU scheduling algorithm can cause the convoy effect, where short processes wait behind a long-running process?
Three processes P1, P2, and P3 arrive at time 0 with burst times 9 ms, 3 ms, and 6 ms respectively. Using Shortest Job First (non-preemptive) scheduling, what is the average waiting time?
In Round Robin scheduling, what happens to the average waiting time as the time quantum becomes very large (approaching infinity)?
Scheduling questions are easiest to get wrong under time pressure. Always sketch a quick Gantt chart on rough paper rather than trying to compute waiting/turnaround times mentally — it takes 20 extra seconds and eliminates silly mistakes.
Process Synchronization (Questions 6–7)
Synchronization questions test whether you understand why race conditions happen and how tools like semaphores prevent them.
What is the primary purpose of a semaphore in process synchronization?
In the classic Producer-Consumer problem with a bounded buffer, what does a binary semaphore initialized to 1 (often called 'mutex') primarily ensure?
Deadlock (Questions 8–9)
Deadlock questions usually test either the four necessary conditions or the idea of a safe state — both are frequent in IBPS SO Professional Knowledge papers.
Which of the following is NOT one of the four necessary conditions for deadlock to occur?
Which statement best describes a safe state in the context of deadlock avoidance?
Memory Management (Questions 10–12)
Paging, segmentation, and fragmentation questions test whether you know which technique solves which problem — a common source of confusion.
A process requires 4,300 bytes of memory and the system uses a page size of 1,024 bytes. How many pages does this process need, and how much internal fragmentation occurs?
Which memory management technique divides a process into variable-size logical units based on the program's own structure, such as functions, arrays, and the stack?
External fragmentation is most commonly associated with which memory allocation approach?
Virtual Memory (Questions 13–14)
Page replacement questions almost always come with a reference string to trace. Practise Belady's Anomaly and the basic algorithms until the trace is second nature.
For the page reference string 1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5 with 3 available frames, how many page faults occur using the FIFO page replacement algorithm?
Which page replacement algorithm is theoretically optimal (produces the minimum possible number of page faults) but is not practically implementable in a real operating system?
File Systems & Disk Management (Question 15)
File allocation and disk scheduling questions round out the OS syllabus and are frequently paired with quick comparison-style MCQs.
Which file allocation method allows direct/random access to any block of a file without traversing preceding blocks, using an index block that stores all block pointers?
Topic-wise Distribution of These 15 Questions
These 15 questions deliberately spread across every major OS subtopic tested in IBPS SO IT Officer Professional Knowledge, rather than concentrating only on scheduling.
| Topic | Questions | Concepts Covered |
|---|---|---|
| Process & Thread Basics | 2 | Process states, state transitions |
| CPU Scheduling | 3 | FCFS, SJF, Round Robin, convoy effect |
| Process Synchronization | 2 | Semaphores, mutex, Producer-Consumer |
| Deadlock | 2 | Necessary conditions, safe state |
| Memory Management | 3 | Paging, segmentation, fragmentation |
| Virtual Memory | 2 | FIFO, Optimal page replacement, Belady's Anomaly |
| File Systems & Disk Management | 1 | File allocation methods |
| Total | 15 | Complete Operating Systems Coverage |
This distribution mirrors how OS is actually weighted in previous-paper and memory-based analyses of IBPS SO IT Officer — scheduling, memory management, and synchronization/deadlock together account for the bulk of OS questions, with file systems contributing a smaller but consistent share.
What Should You Revise After These 15 Questions?
Treat this list as a revision checkpoint for OS specifically. Here's the full topic checklist to work through before you consider OS "exam-ready."
Process Management
- Process states and the process control block (PCB)
- Context switching
- Process vs. thread
- Multithreading models
CPU Scheduling
- FCFS, SJF (preemptive and non-preemptive), Round Robin, Priority Scheduling
- Gantt chart construction
- Waiting time, turnaround time, and response time calculations
- Convoy effect and starvation
Process Synchronization
- Critical section problem
- Peterson's solution
- Semaphores (binary and counting)
- Classic problems: Producer-Consumer, Readers-Writers, Dining Philosophers
- Monitors
Deadlock
- Four necessary conditions
- Deadlock prevention, avoidance, detection, and recovery
- Banker's Algorithm and safe state
- Resource Allocation Graphs
Memory Management
- Contiguous allocation and partitioning
- Internal vs. external fragmentation
- Paging and page tables
- Segmentation and segmented paging
Virtual Memory
- Demand paging
- Page replacement algorithms: FIFO, LRU, Optimal, Second-Chance
- Belady's Anomaly
- Thrashing and the working set model
File Systems & I/O
- File allocation methods: contiguous, linked, indexed
- Directory structures
- Disk scheduling algorithms: FCFS, SSTF, SCAN, C-SCAN
- I/O buffering basics
Knowing the definition of Belady's Anomaly and correctly tracing a FIFO page-replacement reference string are two different skills. The same is true for scheduling calculations and fragmentation problems — pair every concept you revise with at least one worked numerical example.
These 15 Questions Are Not Enough — Practice at Exam Level
OS questions in the actual Mains exam often combine two concepts in one scenario — a scheduling question that also asks about starvation, or a memory question that expects you to compute fragmentation and identify the allocation technique. The only way to get fast and accurate at this is timed, varied practice.
Revise → Practice → Analyse → Revise Weak Areas → Repeat
Attempt an IBPS SO IT Officer Mock Test
Move from concept revision to exam-style practice with MockSensei's free, timed IBPS SO IT Officer mock tests — including topic-wise Operating System questions.
Final Takeaway
These 15 questions are best used as a quick revision checkpoint for the Operating Systems portion of Professional Knowledge, ideally alongside the complete 15 Most Expected Questions guide covering DBMS, Networks, DSA, and Cybersecurity. With Mains on 1 November, the priority now is coverage and speed — revise every subtopic above, work through numerical questions on paper, and get comfortable spotting the concept being tested within the first few seconds of reading a question.
Revise the concepts. Trace the calculations. Analyse your mistakes. Then practise under exam conditions.