FCFS Scheduling

Duration: 10 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 presents a comprehensive educational session on the First Come First Serve (FCFS) CPU scheduling algorithm, a fundamental topic in operating systems. The instructor begins by defining FCFS as the simplest scheduling algorithm, emphasizing that the process requesting the CPU first is allocated the CPU first. Key characteristics are highlighted on the slide: implementation is managed by a FIFO (First In First Out) queue, and the algorithm is always non-preemptive in nature. The instructor uses a visual analogy of a queue at a ticket counter to reinforce the concept. Following the theoretical introduction, the lecture transitions into a practical numerical problem. A table is displayed listing five processes (P0, P1, P2, P3, P4) with their respective Arrival Times (AT) and Burst Times (BT). The instructor systematically solves the problem by first identifying the process with the earliest arrival time (P2 at time 0) to start the execution. He then constructs a Gantt chart at the bottom of the screen to visualize the sequence of process execution over time. Based on the Gantt chart, he calculates the Completion Time (CT) for each process. Subsequently, he computes the Turn Around Time (TAT) using the formula TAT = CT - AT and the Waiting Time (WT) using the formula WT = TAT - BT. The session concludes with the calculation of the average Turn Around Time and average Waiting Time for the set of processes, providing a complete performance analysis of the FCFS algorithm.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the FCFS algorithm. The slide displays the title 'FCFS (FIRST COME FIRST SERVE)' and bullet points stating it is the simplest scheduling algorithm, managed by a FIFO Queue, and is non-preemptive. The instructor explains that the process requesting the CPU first gets it first, using a background image of a queue to illustrate the concept. He underlines key terms like 'simplest' and 'FIFO Queue' on the slide.

  2. 2:00 – 5:00 02:00-05:00

    The instructor sets up a numerical problem. A table appears with columns for P. No, Arrival Time (AT), and Burst Time (BT). The processes are P0 (AT=2, BT=4), P1 (AT=1, BT=2), P2 (AT=0, BT=3), P3 (AT=4, BT=2), and P4 (AT=3, BT=1). He identifies P2 as the first process because it has the earliest arrival time (0). He draws a Gantt chart, placing P2 from time 0 to 3. He then places P1 (arrived at 1) from 3 to 5, followed by P0 (arrived at 2) from 5 to 9, P4 (arrived at 3) from 9 to 10, and finally P3 (arrived at 4) from 10 to 12. He writes the process names and time intervals on the Gantt chart.

  3. 5:00 – 10:00 05:00-10:00

    The instructor meticulously fills the table with calculated values. For process P2, he calculates Completion Time (CT) as 3, Turn Around Time (TAT) as 3-0=3, and Waiting Time (WT) as 3-3=0. For P1, CT is 5, TAT is 5-1=4, and WT is 4-2=2. For P0, CT is 9, TAT is 9-2=7, and WT is 7-4=3. For P4, CT is 10, TAT is 10-3=7, and WT is 7-1=6. For P3, CT is 12, TAT is 12-4=8, and WT is 8-2=6. He then calculates the averages: Average TAT is (3+4+7+7+8)/5 = 5.8, and Average WT is (0+2+3+6+6)/5 = 3.4. He writes these final calculations at the bottom of the table, showing the summation and division steps.

  4. 10:00 – 10:04 10:00-10:04

    The video concludes with a final view of the completed table and Gantt chart, summarizing the entire solution process for the FCFS scheduling problem. The instructor stands next to the screen, indicating the end of the numerical example.

The lecture provides a clear progression from theoretical definition to practical application. It establishes FCFS as a non-preemptive, FIFO-based algorithm and then immediately demonstrates its execution logic through a step-by-step numerical example. By manually constructing the Gantt chart and deriving performance metrics like Turn Around Time and Waiting Time, the instructor illustrates how arrival times dictate the execution order and how these factors impact overall system efficiency. The final calculation of averages offers a quantitative measure of the algorithm's performance for the given set of processes.

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