Best Fit Policy

Duration: 5 min

This video lesson is available to enrolled students.

Return to /learn/DSSSB-TGT-COMPUTER-SCIENCE-PAPER-2/operating-system/memory-management/contiguous-allocation/asset-best-fit-policy after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. Programming, Data Structures, OOP & Java: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Java, OOPS with C++, Java Fundamentals, Array, String, IO & References, Language Design, Intro to Compilers, Visual Basics, Syntax Analysis: Bottom-Up, Object Oriented Technology
  3. Computer Networks, TCP/IP & Network Security: Introduction to CN, Data Communication, DLL: Flow Control, DLL: Access Control, DLL: Error Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Access Technologies, Network Security, Society, Law & Ethics, Cloud Computing, Mobile Computing, Net Layer:Routing Protocol, Cyber Safety and Security
  4. Teaching Methodology: Child Development, Concept of Pedagogy, Theories, Inclusive Education, Experiential Pedagogy, Assessment & Evaluation, Curriculum Framework & Reforms, National Education Policy (NEP) 2020, Psychology, Teaching-Learning Process, Personality Development, Teaching Methods & Strategies, Learning and Motivation, Learners & Learning Process, Factors Affecting Teaching, Methods of Teaching, Nature, Objectives & Characteristics of Teaching, Teaching-Learning Aids & ICT Integration, Classroom Management & Communication, Evaluation, Assessment & Measurement, Curriculum & School Environment, Inclusive Education & Special Needs, Professional Development & Ethics
  5. Digital Electronics / Boolean Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Analog-Digital Conversion
  6. Operating Systems & Linux: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, File Management, Disc Scheduling, Unix OS, Linux OS, Distributed Systems, Windows OS
  7. Data Base Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, File Organization & Indexing, Transaction Management, Concurrency Control, Database Security & Authorization, Database Recovery, Data Warehousing & Mining
  8. Internet & Web Technologies: Website, Browser & Services, Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, HTML Basics, CSS, Emerging Technologies, JavaScript-Basics, .Net Programming, Electronic Data Interchange and E-Commerce, XML
  9. Computer Fundamentals, IT Basics & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer, Terms & Abbreviations, MS Office Applications, Instr Formats & Modes, Floating Point Rep
  10. Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  11. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, extras, Fundamentals of Systems and Information Systems
  12. Design & Analysis of Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  13. Mathematics - I, II, III, IV: Permutation and Combination, Logarithm, Linear Algebra, Algebra, Calculus, Trigonometry, Vectors, Set Theory, Functions, Relations, Propositional and Predicate Logic, Research Process Steps, Graph Theory
  14. Computer Graphics, Multimedia & Mobile Computing: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing, Multimedia
  15. Emerging Trends: Emerging Tech Trends, Knowledge Representation, Natural Language Processing
  16. Statistical Techniques: Probability, Statistics
  17. Interpolation - DI: Data Interpretation
  18. Basis of Physics: Physics
  19. Previous Year Paper:
  20. Business Studies and Management: Business Communication, Business Organization and Management, Financial Accounting, Business Economics, Management Information System (MIS), Knowledge Management & New Economy
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The lecture provides a detailed explanation of the "Best fit policy" used in operating system memory management. The instructor defines the policy as a strategy where the system searches the entire available memory to locate and allocate the smallest partition that is large enough to hold the incoming process. He contrasts this with other policies by highlighting its specific advantages and disadvantages. The core takeaway is that while Best Fit minimizes wasted space in fixed-size partitioning, it is computationally expensive and leads to severe external fragmentation in variable-size partitioning schemes due to the creation of many tiny, unusable memory holes.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The session begins with the instructor standing next to a slide titled "Best fit policy." The slide text explicitly defines the method: "Here, we search the entire memory and will allocate the smallest partition which is capable enough." The instructor elaborates on the bullet points. He points to the "Advantage" section, stating the policy "perform[s] best in fix size partitioning scheme." He then moves to the "Disadvantage" section, noting it is "difficult to implement" and "perform[s] worst in variable size partitioning as the remaining spaces which are of very small size." Towards the end, he prepares to draw a diagram on the whiteboard area below the text.

  2. 2:00 – 5:00 02:00-05:00

    The instructor demonstrates the Best Fit algorithm using a visual memory map. He draws a long rectangle representing memory and writes numbers above it: 8, 5, 20, 25, and 40, representing available partition sizes. He introduces a process request of size 23, which he circles. He explains that the algorithm scans the list and selects the partition of size 25 because it is the smallest one that can accommodate the 23-unit process. He shades the 25-block with diagonal lines to indicate it is now allocated. He points out that 2 units of space remain (25 - 23 = 2), creating a small fragment. He then draws a second, more complex diagram above the first one to show a scenario with partitions 20, 2, 5, and 30, illustrating how fragmentation accumulates over time.

  3. 5:00 – 5:17 05:00-05:17

    In the final moments, the instructor focuses on the second diagram he drew. He points specifically to the partition of size 30 and the small gap of size 2 next to it. He has written a circled "28" indicating a process size. He uses this visual to reinforce the concept of external fragmentation. He explains that even though there is free space available in the memory (the 20, 2, and 5 blocks), it might not be contiguous enough to satisfy a large request, demonstrating why the policy performs poorly in variable-size partitioning. He concludes the segment by gesturing towards the fragmented blocks to emphasize the inefficiency.

The video successfully bridges the gap between theoretical definitions and practical memory management issues. By starting with the slide text and moving to a hand-drawn diagram, the instructor makes the abstract concept of "Best Fit" concrete. The progression from defining the policy to showing the specific calculation (25 - 23 = 2) and then illustrating the long-term consequence (fragmentation) provides a comprehensive understanding. The visual cues of shading allocated blocks and circling process sizes are crucial for students to follow the logic of the algorithm.

Loading lesson…