(SEM IV) THEORY EXAMINATION 2018-19 OPERATING SYSTEM

OPERATING SYSTEM – B.Tech (Semester IV), RCS-401

This is a 3-hour, 70-mark written examination designed to evaluate a student’s understanding of operating system concepts, including process management, CPU scheduling, synchronization, memory management, deadlocks, file systems, and disk scheduling.

The paper is divided into three main sections, testing conceptual knowledge, descriptive understanding, numerical/application skills, and algorithm-based problem solving.
 

SECTION A — Short Answer / Conceptual Questions (2 × 7 = 14 Marks)

This section contains seven brief, direct questions to test basic OS concepts.

Topics include:

Elements of Process Control Block (PCB)                   CPU scheduling criteria

Role of Memory Management Unit (MMU)               Seek time & latency time

SCAN and C-SCAN disk scheduling                           Safe vs Unsafe state in deadlock avoidance

Logical vs physical address space (with diagram)

These questions assess quick recall and fundamental understanding.
 

SECTION B — Descriptive / Analytical Questions (7 × 3 = 21 Marks)

Attempt any 3 out of 5.
This section requires explanations, diagrams, algorithm execution, and working steps.

Topics include:

Definition of process + process state transition diagram              Batch operating system explanation

Critical section problem & requirements for a correct solution     Page replacement algorithms (FIFO & Optimal) with detailed execution using a reference string

Disk scheduling calculations (SSTF & FCFS) for given cylinder requests

This section evaluates the student’s ability to apply OS algorithms and analyze system behavior.
 

SECTION C — Long Answer / Detailed Questions (7 marks each)

Each question offers choice (a or b).
These require strong conceptual clarity, problem solving, or algorithmic computation.

Q3 – OS Structures & Functions

Operating System definition + OS functions

Monolithic, layered, and microkernel structures

Q4 – Synchronization Mechanisms

Semaphores, busy waiting removal, binary semaphores

Classical Producer-Consumer problem as synchronization example

Q5 – Scheduling & Deadlock (Numerical)

FCFS & Preemptive SJF scheduling → waiting & turnaround times

Banker’s algorithm:

Need matrix                    Safe state check

Q6 – Memory Management

Paging with example + Paging vs Segmentation

External vs internal fragmentation + paging as a solution

Q7 – File Systems

File definition + file access methods

Short notes:

File system protection & security

Linked file allocation method

This section checks advanced OS knowledge, computational accuracy, and ability to explain OS mechanisms clearly.
 

OVERALL PURPOSE OF THE EXAM

This question paper tests whether the student can:

Understand how operating systems manage processes, memory, files & devices

Apply OS algorithms (scheduling, page replacement, banker’s algorithm)

Solve practical OS problems involving deadlocks, fragmentation & disk scheduling

Explain OS structures (kernel types) and synchronization tools (semaphores)

Understand memory management (paging, segmentation, MMU)

Describe file system operations and protections

It evaluates both theoretical OS foundations and algorithmic / problem-solving abilities, essential for system programming, OS design, and application development.