Practice Question

Duration: 11 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, Physics
  19. GS Paper | 05 | Elementary Maths: Number System, Divisibility Rules, HCF LCM, Percentage, Profit and Loss, Simple Interest and Compound Interest, Ratio and Proportion (Ratios), Average, Time and Work, Speed Time and Distance, Algebra, Mensuration and Geometry, Data Interpretation, Arithmetic, Statistics, Probability, Sequence and Series (Series), Mixture and Alligation, Calculus, Trigonometry, Vectors
  20. GS Paper | 06 | Indian Polity and Governance: Polity
  21. GS Paper | 07 | Current Events: GK- 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.

This lecture demonstrates how to calculate Average Turnaround Time (TAT) and Average Waiting Time (WT) using the First Come First Serve (FCFS) scheduling algorithm. The instructor works through two practice problems on a whiteboard, using a table with columns for Process Number, Arrival Time (AT), Burst Time (BT), Completion Time (CT), TAT = CT - AT, and WT = TAT - BT. For the first problem, processes P0 (AT 0, BT 3), P1 (AT 2, BT 2), and P2 (AT 6, BT 4) are scheduled in arrival order. A Gantt chart shows P0 running from 0 to 3, P1 from 3 to 5, an idle gap from 5 to 6, and P2 from 6 to 10. Completion times are 3, 5, and 10, giving TAT values of 3, 3, and 4, and WT values of 0, 1, and 0. The instructor writes Avg TAT = 10/3 and Avg Waiting Time = 1/3. A second problem uses processes with AT 0, 0, 1 and BT 4, 6, 3. The Gantt chart shows P0 from 0 to 4, P1 from 4 to 10, and P2 from 10 to 13, with CT values 4, 10, 13, TAT values 4, 10, 12, and WT values 0, 4, 9. The instructor writes Avg TAT = 24/3 and Avg WT = 13/3. Ready and Run state diagrams are used to track which processes are waiting and which is executing.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The whiteboard displays the question: 'Calculate the Average Turnaround Time (TAT) and Average Waiting Time (WT) using the FCFS (First Come First Serve) Scheduling Algorithm.' A table is set up with columns P. No, Arrival Time (AT), Burst Time (BT), Completion Time (CT), TAT = CT - AT, and WT = TAT - BT. Rows show P0 (AT 0, BT 3), P1 (AT 2, BT 2), P2 (AT 6, BT 4), and an empty Average row. The instructor begins drawing a green Gantt chart below the table and labels Ready and Run states in a diagram.

  2. 2:00 – 5:00 02:00-05:00

    The instructor builds the Gantt chart for the first problem: P0 runs from 0 to 3, P1 from 3 to 5, an idle gap is marked in red from 5 to 6, and P2 runs from 6 to 10. Time markers 3, 5, and 6 are written beneath the chart. He then fills the table with pink values: CT 3, 5, 10 and TAT 3, 3, 4. Red checkmarks and circles mark the AT values 0, 2, 6 and BT values 3, 2, 4, confirming the input data before computing derived columns.

  3. 5:00 – 10:00 05:00-10:00

    The instructor completes the first problem by writing Avg Waiting Time = 1/3 and Avg TAT = 10/3 on the right side of the board, alongside Ready and Run circles containing P0, P1, P2. He then introduces a second problem with a new table headed Prd, AT, BT, CT, TAT, WT showing arrival values 0, 0, 1 and burst values 4, 6, 3. He sketches a green Gantt bar and a two-circle diagram labeled 'Ready P0, P1' and 'Run' with a magenta 'FCFS' label, circling the zero arrival entries for P0 and P1.

  4. 10:00 – 11:01 10:00-11:01

    The second problem is completed on the board. The table shows CT values 4, 10, 13 and a TAT-BT/WT column listing 0, 4, 9. The instructor writes Avg TAT = 24/3 and Avg WT = 13/3. A green Gantt chart at the bottom displays P0, P1, P2 with time markers 4, 10, 13, confirming the execution order P0 (0-4), P1 (4-10), P2 (10-13).

The lecture teaches FCFS scheduling through two worked examples. The method is: (1) list processes by arrival time; (2) draw a Gantt chart showing execution order, including idle gaps when no process is ready; (3) compute CT from the Gantt chart; (4) compute TAT = CT - AT; (5) compute WT = TAT - BT; (6) average TAT and WT across all processes. Key evidence: first problem yields CT 3, 5, 10; TAT 3, 3, 4; WT 0, 1, 0; Avg TAT = 10/3; Avg WT = 1/3. Second problem yields CT 4, 10, 13; TAT 4, 10, 12; WT 0, 4, 9; Avg TAT = 24/3; Avg WT = 13/3. The Ready/Run diagram helps track which processes are waiting versus executing. Idle time in the Gantt chart (e.g., 5 to 6 in the first problem) does not contribute to any process's execution but affects completion times of later processes.

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