Operating Systems - VIPENGELE Roadmap
Hello friend, Do not roam in the bush. This is exactly all you need in order to know and understant the entire OS. It is not hard, you just need a roadmap to follow. I guarantee you to pass then come back and buy me potatoes.
Step 1. Introduction to Operating Systems
Primary Source: NESO Academy
i. Key Concepts:
- Definition and Purpose of OS: What is an OS? Why do we need it?
- Types of OS:
- Time-sharing, Distributed, Real-time, Embedded, Mobile
- OS Structures:
- Monolithic, Microkernel, Layered, Modular, Hybrid (The Question about Monolithic Kernel is popular)
ii. Study Focus:
- Understand the role of OS as resource manager
- Compare different OS architectures
- Know when each OS type is used
Step 2. Process Management
Primary Source: NESO Academy
Secondary: TutorialsPoint
i. Must Know Topics:
- Process vs Program: Know the difference and relationship
- Process States: New, Ready, Running, Waiting, Terminated
- PCB (Process Control Block): What it contains and why it is important
- Scheduling Types: Preemptive vs Non-preemptive
- Scheduling Algorithms: FCFS, SJF, Round Robin, Priority, Multilevel Queue
- IPC (Inter-Process Communication): How processes talk to each other
- Threads: Single vs Multi-threading concepts
- Context Switching: How and why it happens
ii. Practice: (Go to a specific subtopic and solve)
- Solve NESO Academy questions
- Practice state transition diagrams
- Calculate scheduling metrics
Step 3. CPU Scheduling
Primary Source: TutorialsPoint + NESO Academy
i. Scheduling Criteria (Understand each very well):
- CPU Utilization, Throughput, Turnaround Time, Waiting Time, Response Time
ii. Scheduling Algorithms (Practice Calculations):
- FCFS (First Come First Served)
- SJF (Shortest Job First) - both non-preemptive and preemptive
- Round Robin
- Priority Scheduling
- Multilevel Queue
iii. Study Strategy:
- Watch NESO Academy videos
- Solve TutorialsPoint practice questions
- Practice numerical problems from lecture notes
- Focus on calculation-based questions - they are exam favorites!
Step 4. Synchronization
Primary Source: TutorialsPoint
Secondary: NESO Academy
i. Critical Topics:
- Race Conditions: What they are and why they’re dangerous
- Critical Section Problem: Requirements and solutions
- Synchronization Hardware: TestAndSet(), Swap() instructions
- Classical Problems (Understand each deeply):
a. Producer-Consumer Problem
b. Readers-Writers Problem
c.Dining Philosophers Problem - Semaphores and Mutexes: How they work, difference between them
- Monitors: High-level synchronization construct
ii. Practice Approach:
- Solve TutorialsPoint synchronization problems
- Understand the solutions to classical problems
- Practice writing pseudocode for synchronization
Step 5. Deadlocks
Primary Source: TutorialsPoint ONLY
i. Deadlock Concepts:
- Characterization: 4 necessary conditions (Mutual Exclusion, Hold and Wait, No Preemption, Circular Wait)
- Prevention: Breaking one of the 4 conditions
- Avoidance: Banker’s Algorithm (Practice this extensively, This question is Must)
- Detection and Recovery: How to find and fix deadlocks
ii. Banker’s Algorithm Focus:
- Practice multiple numerical examples
- Understand Safe vs Unsafe states
- Be able to apply the algorithm step-by-step
iii. Study Tip:
- This is calculation section practice makes perfect!
- Solve all TutorialsPoint deadlock questions
Step 6. Memory Management
Primary Source: TutorialsPoint ONLY
i. Key Areas:
- Memory Allocation: Contiguous vs Non-contiguous
- Swapping: Moving processes between memory and disk
- Paging: Concept, page tables, TLBs
- Segmentation: Memory divided into logical segments
- Virtual Memory: Making memory appear larger than physical RAM
- Demand Paging: Loading pages only when needed
- Page Replacement Algorithms:
- FIFO, LRU, Optimal, LFU, MRU
- Thrashing: What it is and how to prevent it
ii. Practice Focus:
- Page replacement algorithm calculations
- Address translation in paging/segmentation
- Understand the cost-benefit of different approaches
Step 7. Storage Management
Primary Source: TutorialsPoint ONLY
i. Disk Terminology (Must Understand):
- Disk Anatomy: Platters, tracks, sectors, cylinders
- Disk Mechanics: Read/write heads, disk arm, rotation speed
- Access Time Components: Seek time, rotational latency, transfer time
ii. Disk Scheduling Algorithms (Practice Calculations!):
- FCFS (First Come First Served)
- SSTF (Shortest Seek Time First)
- SCAN (Elevator Algorithm)
- C-SCAN (Circular SCAN)
- LOOK and C-LOOK
iii. Study Strategy:
- Understand how each algorithm reduces seek time
- Practice numerical problems with given disk queues
- Compare advantages/disadvantages of each algorithm
TOPICS TO SKIP - DO NOT STUDY:
- File Systems
- Input/Output Systems
- Protection and Security
These topics are excluded from our syllabus! Study them for your own advantage
4-Hour Study Plan
Hour 1: Master process states, PCB, and CPU scheduling algorithms (FCFS, SJF, Round Robin) with practice calculations.
Hour 2: Understand synchronization, race conditions, semaphores, and deadlock conditions with Banker’s Algorithm practice.
Hour 3: Learn memory management, paging, virtual memory, and page replacement algorithms (FIFO, LRU, Optimal).
Hour 4: Study disk structure, scheduling algorithms (SSTF, SCAN, C-SCAN), and full review with problem solving.
Exam Strategy
i. High-Marks Topics:
- CPU Scheduling Algorithms (calculations)
- Deadlock Banker’s Algorithm
- Synchronization Problems
- Page Replacement Algorithms
- Disk Scheduling Algorithms
ii. Question Types to Expect:
- Numerical calculations (scheduling, paging, disk)
- Conceptual explanations (process states, deadlock conditions)
- Problem-solving (synchronization, classical problems)
- Comparisons (different algorithms/approaches)
iii. Final Tips:
- Practice calculations - they are having the most marks.
- Understand the “why” behind each concept
- Draw diagrams for process states, scheduling, etc.