SRTF Scheduling

Duration: 7 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.

This educational video provides a comprehensive analysis of the Shortest Remaining Time First (SRTF) scheduling algorithm, emphasizing its pre-emptive nature and optimality in minimizing average waiting time. The instructor begins by defining SRTF as a dynamic scheduling method where the CPU is allocated to the process with the smallest remaining burst time. A critical feature highlighted is that whenever a new process enters the ready state, a scheduling decision is immediately triggered. If this new process has a smaller CPU burst requirement than the remaining time of the currently running process, pre-emption occurs. The video establishes that this specific version of SRTF is considered optimal because it guarantees the minimal average waiting time among all scheduling algorithms. The instruction then transitions to practical application, utilizing a structured table format with columns for Arrival Time (AT), Burst Time (BT), Completion Time (CT), Turn Around Time, and Waiting Time. The instructor demonstrates the algorithm by populating these tables with numerical data for processes P0 through P4, showing specific values such as an Arrival Time of 1 and Burst Time of 7 for the first process. Visual aids include a hand-drawn timeline at the bottom of the screen, which marks intervals and process identifiers like P0 to visualize execution order. The instructor modifies burst times for processes, changing values from 7 to 6 and 5 to 4, to illustrate how changes in input affect the scheduling outcome. A Gantt chart is constructed below the table, correlating visual bars with calculated time metrics. The segment concludes with a correction note regarding a calculation typo, reinforcing the importance of accuracy in deriving Turn Around Time as Completion Time minus Arrival Time.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video introduces the Shortest Remaining Time First (SRTF) algorithm, explicitly defining it as a pre-emptive scheduling strategy. On-screen text states 'Shortest Remaining Time First (SRTF) (Pre-emptive)' and explains the core logic: 'whenever a process enters in ready state, again we make a scheduling decision.' The instructor details that if the new process has a 'smaller CPU burst requirement than the remaining CPU burst of the running process,' the current process is pre-empted. The segment concludes with a definitive statement on the algorithm's efficiency, noting 'This version (SRTF) is also called optimal is it guarantee minimal average waiting time.' This theoretical foundation sets the stage for subsequent numerical examples.

  2. 2:00 – 5:00 02:00-05:00

    The instruction shifts to a practical demonstration using a scheduling table with columns for Arrival Time, Burst Time, Completion Time, Turn Around Time, and Waiting Time. The screen displays process rows P0 through P4 populated with numerical data, such as 'Arrival Time 1 and Burst Time 7 for the first process.' A hand is seen drawing a timeline at the bottom, marking intervals and process identifiers like P0. One frame shows a completed table with handwritten calculations, including 'Turn Around Time derived as 8 minus 1 equals 7.' The instructor modifies burst times for P0 (changing 7 to 6) and P1 (changing 5 to 4), demonstrating the dynamic nature of SRTF. A man appears on screen explaining steps while pointing at row P2, and the timeline progresses with numbers 0, 1, 2, 3, and 4 indicating time units.

  3. 5:00 – 6:44 05:00-06:44

    The final segment consolidates the SRTF analysis by displaying a table with process details (P.No, Arrival Time, Burst Time) and constructing a Gantt chart below it. The instructor points at the chart to explain the progression of execution blocks P0, P1, and P2. The screen displays text labels including 'Arrival Time', 'Burst Time', 'Completion Time', 'Turn Around Time', and 'Waiting Time' alongside the header 'SRTF Scheduling'. A correction note is displayed regarding a calculation typo, emphasizing precision in the derivation of metrics. The visual correlation between table values and Gantt chart bars is maintained throughout, ensuring students understand how the abstract calculations translate into a visual timeline of process execution.

The video systematically progresses from theoretical definition to practical application, ensuring students grasp both the logic and implementation of SRTF. The core concept is pre-emption based on remaining burst time, which distinguishes it from non-pre-emptive Shortest Job First. The optimality claim is supported by the algorithm's ability to minimize average waiting time, a critical metric in operating systems. The use of tables and Gantt charts provides a dual representation: quantitative data for calculation practice and visual timelines for conceptual understanding. The instructor's modifications to burst times illustrate the algorithm's responsiveness, while the correction note highlights common pitfalls in manual calculation. This structured approach allows learners to verify their own computations against the visual evidence provided.

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