First Fit Policy

Duration: 6 min

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Inside: a video lesson and guided study material.

Module outline

  1. General Intelligence & Reasoning: Analogy, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Logical Sequence Of Words, Syllogisms, Venn Diagram, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Data Sufficiency, Puzzle Solving (Puzzles), Data Arrangement, Cubes & Dices, Calendar, Clock, Arithmetic, Number System, HCF LCM, Verbal Analogy (Word Based Analogy), Visual Recognition and Figure Completion, Paper Folding and Cutting, Transformation of Shapes, Clocks and Calendars, Direction Sense, Cubes and Dice, Patterns in Two-Dimensional Figures, Seating Arrangements, Analogy and Classification, Logical Deduction and Induction, Alphabet and Word Tests, Mathematical Operations, Series Completion, Simplification and Approximation, Coding and Decoding, Numerical Reasoning, Assembling and Grouping of Shapes, Three-Dimensional Patterns and Visualization, Vocabulary, Number System, Averages, Mixtures and Alligation, Simple and Compound Interest, Percentages, Algebra, Speed, Time and Distance, Seating and Arrangement Puzzles, Traverse Surveying, Order, Ranking and Sequence, Constraint Puzzles, Syllogisms and Venn Diagrams, Reading Comprehension, Critical Reasoning, Permutations and Combinations, Narrative Sequencing, Project Monitoring, Resources and Safety, Profit, Loss and Discount, Ratio and Proportion, Time and Work, Mensuration, Data Interpretation, Powers, Surds and Logarithms, Sequences and Series, Articles and Determiners, Sentence Completion, Data Sufficiency, Blood Relations, Simple Interest and Compound Interest, Mixture and Alligation, Sequence and Series (Series), Speed Time and Distance, Algebra, Profit and Loss, Powers and Exponents (Surds and Indices), Permutation and Combination
  2. General Awareness: Physics, Chemistry, Biology, History, Geography, Polity, Indian Economy, Environment, Static General Knowledge, GK- Current Affairs, Artificial Intelligence, MS Office Applications, Terms & Abbreviations, Keyboard Shortcuts, Evolution of Indian Banking (Banking & Financial Awareness), Emerging Tech Trends
  3. Engineering Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Linear Algebra, Calculus, Probability, Statistics, Signal Space and Optimum Detection, Probability, Statistics
  4. Digital Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep, Number Systems and Codes, Registers and Counters, Boolean Algebra and Logic Gates, Microprocessors and Microcontrollers, Logic Families and CMOS Logic, Microprocessors, Logic Gates and Boolean Algebra, Minimization of Boolean Functions, Timing, Hazards and Testing, Logic Families, Combinational Logic Design, Arithmetic Circuits, Waveform Generators and Timer Circuits, Semiconductor Memories and Programmable Logic Devices, Combinational Logic Circuits, Latches and Flip-Flops, Finite State Machines, Sequential Circuits and State Machines, Minimization of Boolean Functions, Arithmetic Circuits, Latches and Flip-Flops, Number Systems and Codes, Registers and Counters
  5. Computer Organisation & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer, Register Transfer and Microoperations, Semiconductor Memories and Programmable Logic, Processor Organization and Instructions, Memory Hierarchy and Input/Output, Registers and Counters
  6. Programming & Data Structures: 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, HTML Basics, OOPS with C++, Java, Object Oriented Technology
  7. Databases: 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, Database Security & Authorization
  8. Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos
  9. Theory of Computation: 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
  10. Compiler Design: 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
  11. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Security, Windows OS, Distributed Systems, Unix OS, Linux OS
  12. Computer Networks: Introduction to CN, 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, Data Communication, Website, Browser & Services, Web Design & Development, Network Security, Cyber Threats and Malware Attacks, Cyber Safety and Security
  13. Full Length Mock Tests:
  14. Sectional Tests:
  15. Paper 2 - Full-length Mock Tests:
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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