720p_8.2 Gate 2007

Duration: 2 min

This video lesson is available to enrolled students.

Return to /learn/ISRO/operating-system/virtual-memory/optimal-replacement/asset-720p-82-gate-2007 after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. General Aptitude & Reasoning: Number System, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Speed Time and Distance, Mixture and Alligation, Data Interpretation, Algebra, Probability, Permutation and Combination, Venn Diagram, HCF LCM, Divisibility Rules, Age Problems, Pipe and Cistern, Partnership, Linear Algebra, Sequence and Series (Series), Statistics, Powers and Exponents (Surds and Indices), Arithmetic, Mensuration and Geometry, Calculus, Trigonometry, Vectors, Speed Mathematics and Basic Mathematics, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analogy, Series (Number and Letter Series) (Numerical Relations and Reasoning), Puzzle Solving (Puzzles), Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Calendar, Seating Arrangements, Coding Decoding, Blood Relations, Directions (Direction Test), Clock, Analytical Reasoning (Counting Figures Reasoning), Ranking, Order and Sequence, Logical Sequence Of Words, Inequality, Data Sufficiency, Cubes & Dices
  3. Computer Networks & Cybersecurity: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware Basics, Network Security
  4. Programming, Data Structures & Algorithms: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  5. AI, Machine Learning, Big Data & Cloud: Emerging Tech Trends, Artificial Intelligence, Big Data Systems, Approaches to AI, Search Algorithms, Knowledge Representation, Cloud Computing
  6. Digital Logic & Computer Organization: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer
  7. TOC & Compiler: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory, Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  8. Discrete Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic
  9. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Distributed Systems
  10. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Object Oriented Technology, HTML Basics, JavaScript-Basics, Java, XML
  11. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Data Warehousing & Mining, Enhanced Data Models, NoSQL
  12. Other Recurring CS Topics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, Multimedia
  13. Live Classes: ISRO Live classes
  14. Full Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a walkthrough of a GATE 2007 operating systems problem concerning page replacement algorithms. The instructor focuses on the Optimal Page Replacement policy, which dictates replacing the page not used for the longest period in the future. The problem involves a process with 3 page frames and initially empty memory. The reference string is 1, 2, 1, 3, 7, 4, 5, 6, 3, 1. The instructor uses a whiteboard to visualize memory frames and page references, tracing the algorithm to determine total page faults.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by writing the reference string "1, 2, 1, 3, 7, 4, 5, 6, 3, 1" on the whiteboard. He draws three vertical boxes to represent the page frames. He processes the first few references: 1 (fault), 2 (fault), 1 (hit), 3 (fault). The frames now contain 1, 2, and 3. When page 7 arrives, he looks ahead at the remaining string (4, 5, 6, 3, 1). He identifies that page 2 is not used again, while 1 and 3 are used later. Consequently, he replaces page 2 with 7. He continues this logic for pages 4, 5, and 6, replacing pages 7, 4, and 5 respectively because they are not referenced in the future.

  2. 2:00 – 2:24 02:00-02:24

    The instructor finalizes the simulation. After processing page 6, the frames contain pages 1, 6, and 3. The remaining references are 3 and 1, which result in hits. He counts the total number of page faults incurred: 1, 2, 3, 7, 4, 5, 6. This sums to exactly 7 faults. He circles option (A) 7 on the screen, confirming it as the correct answer to the GATE question.

The lecture effectively demonstrates the application of the Optimal Page Replacement algorithm by manually tracing a reference string. The core concept is minimizing faults by replacing the page that will not be needed for the longest time. The instructor's method of looking ahead and identifying unused pages simplifies the complex logic into a clear, countable process. This visual approach helps students understand how to manually trace the algorithm, leading to the final answer of 7 page faults for the given sequence.

Loading lesson…