First In First Out Page Replacement Algorithm

Duration: 7 min

This video lesson is available to enrolled students.

Return to /learn/BTSC-LAB-ASSISTANT/operating-systems/virtual-memory/fifo-page-replacement/asset-first-in-first-out-page-replacement-algorithm after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: BTSC About Course
  2. Basics of Computer Science: Basics of COA, Number System, Number Representation
  3. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory
  4. Data Structures & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms
  5. Database Management Systems(DBMS): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Relational Algebra, SQL, Transaction Management, Concurrency Control, Database Recovery
  6. Networking and Internet: Introduction to CN, Data Communication, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Application Layer, Hardware Basics, Network Access Technologies, Network Security
  7. Cyber Security Basics: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Electronic Data Interchange and E-Commerce, Cyber Safety and Security
  8. C Programming (Programming Fundamentals): C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  9. C++, OOPs & Java (Programming Fundamentals): Java, OOPS with C++
  10. Python (Programming Fundamentals): Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules
  11. Web Development Basics: Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, JavaScript-Basics, HTML Basics
  12. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing
  13. Software and Hardware Tools: MS Office Applications, Unix OS, Linux OS
  14. Emerging Trends. AI & Social Ethics: Artificial Intelligence, Emerging Tech Trends, Society, Law & Ethics
  15. Full Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a comprehensive lecture on the First In First Out (FIFO) Page Replacement Algorithm used in operating systems. The instructor begins by defining the core logic of FIFO, where the oldest page in memory is selected for replacement. He then walks through a detailed, step-by-step example using a specific page reference string and three memory frames to demonstrate the replacement process and calculate the total number of page faults. Finally, the lecture concludes by discussing a critical limitation of the algorithm known as Belady's Anomaly, explaining how increasing the number of allocated frames can paradoxically increase the page fault rate.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The lecture introduces the First In First Out (FIFO) Page Replacement Algorithm. The on-screen text defines the algorithm as one that 'associates with each page, the time when that page was brought into memory.' The instructor explains the primary rule: 'When a page must be replaced, the oldest page is chosen.' This establishes the fundamental principle that the first page to enter memory is the first to be evicted, creating a queue-like structure for page management.

  2. 2:00 – 5:00 02:00-05:00

    The instructor demonstrates the algorithm using a page reference string: 7 0 1 2 0 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1. He constructs a table with three page frames to track the state of memory. As he processes the sequence, he shows how pages are loaded and replaced. For instance, when the reference '2' arrives, the oldest page '7' is replaced. He circles specific numbers to highlight the replacement logic. The section concludes with the text 'In the above example the number of page fault is 15,' quantifying the algorithm's performance for this specific case.

  3. 5:00 – 6:33 05:00-06:33

    The final segment discusses a significant drawback of the FIFO algorithm called Belady's Anomaly. The slide text states: 'for some page-replacement algorithms, the page-fault rate may increase as the number of allocated frames increases.' The instructor explains that this is counter-intuitive because typically, adding more memory frames should reduce page faults. However, in FIFO, increasing the frame count can lead to more frequent page faults, highlighting a performance limitation of the algorithm.

The video progresses logically from theory to practice and finally to critical analysis. It starts by defining FIFO as a simple algorithm based on arrival time, moves to a detailed walkthrough of a 20-step page reference sequence to calculate 15 page faults, and concludes by identifying Belady's Anomaly as a significant drawback where increasing resources degrades performance. This structure helps students understand not just how the algorithm works, but also its practical limitations in real-world scenarios.

Loading lesson…