IT241 Operating System
Operating System notes
10 chapter notes, in syllabus order. Each starts with the key points.
Unit 1
OS Basics: Definitions, Functions, Services & EvolutionUnit 1 of Operating System introduces the core concepts of operating systems, including their definitions, functions, services, and historical evolution, along with their role in modern computing systems.16 min readUnit 2
Processes & Threads: Definitions, States, Models & MultithreadingUnit 2 of Operating System covers the core concepts of processes (PCB, states, creation/deletion), threads (lightweight processes, types, advantages), inter-process communication (IPC), and real-world applications in banking, e-commerce, and mobile apps like Khalti or Pathao.6 min readUnit 3
CPU Scheduling: Algorithms, Metrics & Real-World ImpactUnit 3 of Operating System explores CPU scheduling fundamentals—how OS selects processes for execution, key algorithms (FCFS, SJF, Round Robin, Priority), performance metrics (turnaround time, waiting time), and their trade-offs. Covers scheduling queues, preemption, and practical applications in banking, e-commerce, a11 min readUnit 4
Process Synchronization: Race Conditions, Critical Sections, Semaphores & DeadlocksUnit 4 of Operating System covers how processes coordinate access to shared resources, avoiding race conditions, starvation, and deadlocks using synchronization techniques like semaphores, monitors, and message passing, with real-world examples from Nepalese apps and systems.14 min readUnit 5
Deadlocks: Conditions, Prevention, Avoidance, Detection & RecoveryUnit 5 of Operating System: Explores deadlocks—how they occur, their four necessary conditions (mutual exclusion, hold-and-wait, no preemption, circular wait), prevention/avoidance strategies, detection algorithms (Banker’s, Wait-For Graph), and recovery methods (abort, rollback, resource preemption). Includes real-wor14 min readUnit 6
Memory Management: Allocation, Swapping, Paging, Segmentation & PerformanceUnit 6 of Operating System: Covers memory management techniques (contiguous, paging, segmentation), allocation strategies (first-fit, best-fit, worst-fit), swapping, memory protection, and performance metrics (hit ratio, page fault rate) with real-world examples from Nepalese apps and hardware.14 min readUnit 7
Virtual Memory: Paging, Segmentation, Demand Paging & ThrashingUnit 7 of Operating System: Explores virtual memory concepts—how systems use paging, segmentation, demand paging, and page replacement algorithms (FIFO, LRU, OPT) to manage memory efficiently, prevent thrashing, and optimize performance in real-world applications like mobile apps and cloud services.17 min readUnit 8
File Systems: Structure, Operations & ManagementUnit 8 of Operating System explores file system architecture, storage management, directory structures, file allocation methods, and performance optimization techniques essential for modern OS design.5 min readUnit 9
I/O Systems, Disk Scheduling, RAID, Buffering & CachingUnit 9 of Operating System: Explores Input/Output (I/O) subsystems, disk management techniques (scheduling, partitioning, RAID), buffering/caching strategies, and their impact on system performance, with real-world examples from Nepalese tech (eSewa, NTC) and global platforms (Google Cloud, YouTube).6 min readUnit 10
OS Protection, Security & Linux Case StudyUnit 10 of Operating System explores protection mechanisms (access control, capabilities), security threats (viruses, DoS), Linux security features (SELinux, AppArmor), and a hands-on case study of Linux’s security architecture, with real-world examples from Nepali tech companies and global platforms.10 min read