Operating Systems (OS) are the heart of all computing devices, from your laptop to your smartphone to enterprise servers. Whether you're pursuing computer science, preparing for GATE or placement interviews, or aiming for roles in system administration and DevOps, understanding OS fundamentals is essential.
The best part? You don’t need a pricey course or textbook. With the right collection of free PDFs, notes, and revision guides, you can learn OS efficiently, at your own pace.
Why Operating System Knowledge Matters in 2025
Mastering OS will help you:
- Understand how programs execute, manage memory, and schedule tasks.
- Crack interviews that demand system-level logic and problem-solving.
- Build performance-optimized code as a developer or engineer.
- Prepare for competitive exams like GATE, UGC-NET, or company-specific tests.
Table: Free Operating System PDFs (Beginner to Advanced)
| S.No | Resource Title | Download Link | Description |
|---|---|---|---|
| 1 | OS Introduction & Functions | Download | Definition, types, and components of operating systems. |
| 2 | Process Management & States | Download | PCB, context switching, process lifecycle. |
| 3 | Scheduling Algorithms Explained (FCFS, SJF etc) | Download | Includes Gantt charts, turnaround time, waiting time. |
| 4 | Memory Management & Paging | Download | Contiguous, non-contiguous memory handling. |
| 5 | Virtual Memory & Demand Paging | Download | Page fault handling, page replacement strategies. |
| 6 | File System Concepts | Download | Directory structures, allocation methods, file access. |
| 7 | Deadlock Detection, Prevention & Recovery | Download | Banker's Algorithm, wait-for graph, starvation handling. |
| 8 | OS Synchronization (Semaphore & Monitors) | Download | Critical section, binary semaphore, bounded buffer problem. |
| 9 | OS System Calls & Kernel Architecture | Download | User mode vs kernel mode, syscall structure. |
| 10 | Disk Scheduling Algorithms | Download | FCFS, SSTF, SCAN, C-SCAN algorithms. |
| 11 | OS MCQs & Objective Type Questions | Download | Ideal for exams and placement tests. |
| 12 | Threads and Multithreading | Download | Multithreading models, user/kernel threads. |
| 13 | Demand Paging vs Segmentation | Download | Use-case comparisons and hybrid systems. |
| 14 | OS Revision Notes (Quick Review PDF) | Download | Fast-track revision before tests. |
| 15 | OS Interview Questions & Answers | Download | Real interview Q&As, conceptual and scenario-based. |
How to Learn OS with These Free PDFs
Start with the intro and process management sections. Once you’re confident, move into memory and file systems. Don’t skip scheduling algorithms—they’re a favorite in exams.
Then dive into deadlocks, semaphores, and system calls. These are tricky but essential. Finally, before any exam or interview, go through the revision notes and interview Q&A PDFs.
FAQs on Free OS Study Material
Q1. Can I use these OS PDFs for university exams and placements?
Yes. These resources are aligned with BTech, MCA, and BCA syllabi and are great for interview rounds in TCS, Infosys, Wipro, Amazon, etc.Q2. What’s the best way to learn scheduling and memory management?
Use the scheduling PDF with Gantt chart visuals and solve practice questions on turnaround/wait time.Q3. Are these notes suitable for GATE/UGC-NET?
Absolutely. The topics, especially synchronization, paging, and deadlocks, are frequent in competitive exams.Q4. How long does it take to finish the OS syllabus using these PDFs?
You can complete everything in 4–6 weeks with 1 hour of focused daily study.
