Best Fit Policy

Duration: 5 min

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Module outline

  1. About Course: About the Course
  2. CS | 01 | Digital Logic and Circuits and Discrete Mathematical Structures: Digital Systems & Boolean Basics, Number System, Number Representation, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Permutation and Combination
  3. CS | 02 | Computer Organization and Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Multiprocessors
  4. CS | 03 | Data Structures and Algorithm: 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, Complexity Theory, Advanced Algorithms
  5. CS | 04 | Problem Solving through C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  6. CS | 05 | Object Oriented Techniques: Object Oriented Technology, Java
  7. CS | 06 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Unix OS
  8. CS | 07 | Database Management Systems: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Database Security & Authorization, Query Processing & Optimization, File Organization & Indexing
  9. CS | 08 | Computer Networks: 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
  10. CS | 09 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  11. CS | 10 | Internet Technology, Web Design and Web Technology: Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, JavaScript-Basics, HTML Basics
  12. CS | 11 | System Analysis And Design: Fundamentals of Systems and Information Systems, SDLC and Development Approaches, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Security, Risk Management & Maintenance
  13. CS | 12 | Information Security and Cyber Laws: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security
  14. CS | 13 | Computer Graphics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing
  15. GS Paper | 01 | Indian and World Geography: Geography
  16. GS Paper | 02 | History: History
  17. GS Paper | 03 | Indian Economy & Social Development: Indian Economy
  18. GS Paper | 04 | General Science: Biology, Chemistry, वैज्ञानिक उपलब्धियाँ और अनुसंधान / Scientific Achievements and Research
  19. GS Paper | 05 | Elementary Maths: संख्या पद्धति / Number System, Divisibility Rules, महत्तम समापवर्तक और लघुत्तम समापवर्त्य / HCF and LCM, प्रतिशत / Percentage, लाभ, हानि और बट्टा / Profit, Loss and Discount, साधारण और चक्रवृद्धि ब्याज / Simple and Compound Interest, अनुपात और समानुपात / Ratio and Proportion, औसत / Average, समय और कार्य / Time and Work, समय, चाल और दूरी / Time, Speed and Distance, Algebra, घन क्षेत्रमिति / Solid Mensuration, आँकड़ा निर्वचन / Data Interpretation, Arithmetic, Statistics, Probability, Sequence and Series (Series), मिश्रण और एलिगेशन / Mixture and Alligation, Calculus, Trigonometry, Vectors, संख्या पद्धति और संख्या सिद्धांत / Number Systems and Number Theory, यूक्लिडीय ज्यामिति और क्षेत्रमिति / Euclidean Geometry and Mensuration, सांख्यिकी और प्रायिकता / Statistics and Probability, निर्देशांक ज्यामिति, सदिश और त्रिविमीय ज्यामिति / Coordinate Geometry, Vectors and 3D Geometry, बहुपद, समीकरण और सम्मिश्र संख्याएँ / Polynomials, Equations and Complex Numbers, समतल क्षेत्रमिति / Plane Mensuration, सरलीकरण, घातांक और करणी / Simplification, Indices and Surds, समुच्चय, संबंध, फलन और विविक्त गणित / Sets, Relations, Functions and Discrete Mathematics
  20. GS Paper | 06 | Indian Polity and Governance: Polity
  21. GS Paper | 07 | Current Events: समसामयिकी / Current Affairs
  22. UPLT Live Classes Notes: UPLT Live Classes
  23. UPLT Full Mock Tests Tier 1:
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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.

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