Vidyarthi AIStudent Career Compass

CS-405RGPV · Sem 4

Operating Systems

RGPV B.Tech Grading System (AICTE model, CBGS-based), II Year CSE · Theory 100: 70 end-sem (3 hrs; 8 questions, attempt any 5, 14 marks each, usually split into two 7-mark parts) + 30 internal (mid-sem tests 20 + quiz/assignment 10). OS practical is marked separately (end-sem practical/viva 30 + lab work and sessional 20).

Official syllabus

Revised 0 of 108 high-repeat questions

One-Night Pass Pack

A process is a program in execution with its own code, data, stack and CPU state. States: New, Ready, Running, Waiting (Blocked), Terminated; transitions: admit, dispatch, timeout/interrupt, I/O wait, I/O done, exit. PCB is the kernel record of a process: PID, state, program counter, CPU registers, scheduling info (priority), memory info (page table/base-limit), open files and I/O status, accounting info. The PCB is saved and loaded during a context switch.
Full-marks tip: Draw the 5-state diagram with every arrow labelled, then a boxed PCB layout. Add one line on context switching for the extra marks. Common mistake: drawing Waiting to Running directly (it must go via Ready).

Exam kal hai? Send this Pass Pack to your batch group.

Unit-wise syllabus

U1Introduction to Operating Systems

Weightage: Not officially published (8 questions, any 5 attempted; questions are not fixed one per unit)

Functions, evolution and types of operating systems (batch, multiprogramming, time sharing, real time)Desirable characteristics and features of an OSOS services and the different ways of providing themUtility programsSystem calls and their types

U2File Systems

Weightage: Not officially published (8 questions, any 5 attempted; questions are not fixed one per unit)

File concept: user's and system programmer's viewDisk and tape organisationModules of a file systemDisk space allocation: contiguous, linked, indexedDirectory structures and file protectionSystem calls for file managementDisk scheduling algorithms (FCFS, SSTF, SCAN, C-SCAN, LOOK)

U3CPU Scheduling and Memory Management

Weightage: Not officially published (8 questions, any 5 attempted; questions are not fixed one per unit)

Process concept, process states, PCBLong, medium and short term schedulersScheduling algorithms (FCFS, SJF, priority, Round Robin) and their evaluationProcess management system calls, multiple-processor scheduling, threadsPartitioning, swapping, paging, segmentation, paged segmentation and their comparisonOverlays, dynamic linking and loadingVirtual memory, demand paging and page replacement (FIFO, LRU, Optimal), thrashing

U4Input/Output, Concurrent Processes and Deadlocks

Weightage: Not officially published (8 questions, any 5 attempted; questions are not fixed one per unit)

I/O principles, speed gap, format conversionProgrammed, interrupt-driven and concurrent I/OReal and virtual concurrency, mutual exclusion, synchronisation, inter-process communicationCritical section problemBinary and counting semaphores, wait and signal operations, classic problemsDeadlock characterisation, prevention, avoidance (Banker's algorithm) and recovery

U5Network, Distributed and Multiprocessor Operating Systems; Case Studies

Weightage: Not officially published (8 questions, any 5 attempted; questions are not fixed one per unit)

Introduction to network operating systemsDistributed operating systemsMultiprocessor operating systemsCase studies: Unix/Linux, Windows and other contemporary OS

Curated video lectures

Free lectures from well-known educators, matched to units. Videos load only when you tap “Watch here”, to save data.

Operating System complete course

Gate Smashers · Playlist · ~92 videos · Hinglish

Operating System complete course

Neso Academy · Playlist · ~77 videos · English

Operating System complete playlist (numericals focus)

KnowledgeGATE by Sanchit Sir · Playlist · ~82 videos · Hinglish

Operating Systems lectures (IIT Bombay)

Mythili Vutukuru (IIT Bombay) · Playlist · ~33 videos · English

Deadlock avoidance: Banker's algorithm with example

Gate Smashers · Single video · Hinglish · Unit 4

Page replacement introduction and FIFO

Gate Smashers · Single video · Hinglish · Unit 3

Exam Guide Radar

Standard textbook

Silberschatz, Galvin and Gagne, Operating System Concepts (Wiley), with Tanenbaum, Modern Operating Systems (PHI) and Dhamdhere, Operating Systems (McGraw Hill) as commonly listed RGPV references

Exam guide students buy

Shivani Publications (RGPV solved-paper and guide series for Operating Systems)

Widely sold around Bhopal and Indore colleges; check the grading-scheme year on the cover.

Local market tip

Buy the Shivani edition labelled for CS-405 IV Sem Grading System (not the old CS-502 5th sem CBGS book) from Bhopal's MP Nagar or college-gate shops before mid-sems, and check the back pages include the latest June/Dec papers.

Lab Viva Survival

CPU scheduling programs (FCFS, SJF, Priority, Round Robin)

Q. What is the difference between preemptive and non-preemptive scheduling?: → Preemptive scheduling can take the CPU away from a running process (RR, SRTF); non-preemptive lets it run until it finishes or blocks (FCFS, SJF).
Q. Which algorithm gives minimum average waiting time?: → SJF (SRTF in the preemptive case) is optimal for average waiting time, but it needs burst times in advance.
Q. What happens if the RR time quantum is very large or very small?: → Very large makes RR behave like FCFS; very small causes too many context switches and overhead.
Q. What is starvation and how is it fixed?: → A low-priority process waiting forever; fixed by aging, which slowly raises its priority.

Banker's algorithm and producer-consumer using semaphores

Q. What is a safe state?: → A state where some order (safe sequence) exists in which every process can get its needed resources and finish.
Q. Why is Banker's algorithm rarely used in real OS?: → It needs maximum demand in advance and a fixed number of processes and resources, and it is costly to run on every request.
Q. Which semaphores are used in bounded-buffer producer-consumer?: → mutex = 1 for buffer access, empty = n for free slots and full = 0 for filled slots.

Page replacement programs (FIFO, LRU, Optimal)

Q. What is a page fault?: → A trap raised when the referenced page is not in main memory, so the OS must load it from disk.
Q. What is Belady's anomaly?: → In FIFO, page faults can increase when the number of frames is increased; LRU and Optimal do not show it.
Q. Why is Optimal page replacement not implementable?: → It needs knowledge of future references, so it is used only as a benchmark.