FCFS Scheduling

Duration: 10 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
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  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
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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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