First Fit Policy

Duration: 6 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 video lecture provides a detailed explanation of memory allocation strategies in operating systems, focusing primarily on the "First fit" policy before briefly introducing the "Best fit" policy. The instructor starts by defining First fit policy, stating on the slide that it involves searching memory from the base and allocating the first partition that is capable enough. He lists the advantages as being simple, easy to use, and easy to understand. Conversely, he notes the disadvantage is poor performance in terms of both time and space. To illustrate this, he draws a memory diagram with partitions of sizes 15, 16, and 30. He demonstrates the allocation of a process of size 5 to the first partition. The lecture then transitions to the Best fit policy, defining it as searching the entire memory to find the smallest capable partition. He notes its advantage in fixed-size partitioning but highlights its disadvantage in variable-size partitioning due to the creation of very small remaining spaces.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the "First fit policy" using a slide that defines it as searching memory from the base to allocate the first capable partition. The slide text explicitly states: "as the name implies, it states searching the memory from the base and will allocate first partition which is capable enough." He lists advantages like being simple, easy to use, and easy to understand. Conversely, he notes the disadvantage is poor performance in terms of both time and space. He begins a visual demonstration by drawing a memory block and marking partitions with sizes 15, 16, and 30. He writes "5" with an arrow pointing to the first partition, indicating a process of size 5 is arriving. He allocates it to the first partition of size 15, leaving 10 units of space.

  2. 2:00 – 5:00 02:00-05:00

    The instructor continues the First fit example, allocating a process of size 10 to the remaining space in the first partition. He then allocates a process of size 12 to the second partition (size 16) and a process of size 30 to the third partition (size 30). He draws a second diagram below to further illustrate the concept, writing numbers like 4, 4, 15, 12, and 30 to represent different partition sizes or process requests. He emphasizes the sequential nature of the search, moving from the base of memory upwards. He circles a number '2' and points to the partitions, explaining how the allocation happens sequentially. He draws hatching lines to indicate allocated memory. He gestures with his hand to show the flow of allocation.

  3. 5:00 – 6:04 05:00-06:04

    The slide transitions to the "Best fit policy". The text explains that this policy searches the entire memory to allocate the smallest partition capable of holding the process. The instructor points out that while it performs best in fixed-size partitioning, it is difficult to implement and performs worst in variable-size partitioning due to the creation of very small remaining spaces. The video ends as he begins to explain this new concept, standing next to the slide which lists the advantages and disadvantages clearly. The slide text reads: "Here, we search the entire memory and will allocate the smallest partition which is capable enough."

The lecture effectively contrasts two memory allocation strategies. First fit is presented as a quick, simple method that might lead to fragmentation, while Best fit is shown as a more precise but computationally expensive method that can lead to external fragmentation. The visual diagrams help clarify how processes are mapped to memory blocks in each scenario. The instructor uses specific numerical examples to make the abstract concepts concrete for the students. The transition from First fit to Best fit highlights the trade-off between speed and efficiency in memory management. Understanding these policies is crucial for optimizing system performance.

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