Process Scheduling & Policies

Duration: 20 min

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Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. Section A: General Awareness: Polity, Physics, Biology, Chemistry, Static General Knowledge, History, Geography, Indian Economy, GK- Current Affairs, Evolution of Indian Banking (Banking & Financial Awareness), Environment
  3. Section A: General Intelligence & Reasoning ability: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Blood Relations, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Directions (Direction Test), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Selection Decision Table (Decision Making), Logical Sequence Of Words, Crypt Arithmetic, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence, TCS NQT Advanced Reasoning Ability
  4. Section A: Arithmetical & Numerical Ability: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Percentage, Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Pipe and Cistern, Mensuration and Geometry, Powers and Exponents (Surds and Indices), Algebra, Probability, Mental Ability, Age Problems, Partnership, Statistics, Arithmetic, Speed Mathematics and Basic Mathematics, Miscellaneous
  5. Section A: English Language & Comprehension: Vocabulary, Subject Verb Agreement (Verb Noun Agreement), Adjectives, Tenses, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Articles, Sentence Construction, Preposition, Direct and Indirect Speech, Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Modals, Active Passive Voice (Voice), Sentence Correction (Error Correction), Adverb, Conjunction, Cloze Test (Cloze Passage)
  6. Section A: Hindi Language & Comprehension: भाषा, लिपि, ध्वनि, वर्ण, अक्षर, स्वर, व्यंजन, मात्रा और संयुक्ताक्षर, वर्तनी, वर्ण-विन्यास, अनुस्वार, अनुनासिक, चंद्रबिंदु और ‘र’ के रूप, शब्द, पद और शब्द-भेद, संज्ञा और सर्वनाम, विशेषण और क्रिया, लिंग, वचन, पुरुष और कारक, काल, वाच्य, वाक्य और वाक्य-भेद, संधि, समास, विलोम शब्द, पर्यायवाची शब्द, सामान्य अशुद्धियाँ, अनेक शब्दों के लिए एक शब्द, मुहावरे और लोकोक्तियाँ, अपठित गद्यांश और अपठित पद्यांश, Multi-Topic Content (Cross-Concept Material), वर्णमाला
  7. Section B: Programming, Data Structures, OOP & Java: 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, Java, OOPS with C++, Language Design, Intro to Compilers, Visual Basics, Syntax Analysis: Bottom-Up, Object Oriented Technology
  8. Section B: Computer Networks, TCP/IP & Network Security: Introduction to CN, Data Communication, DLL: Flow Control, DLL: Access Control, DLL: Error Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Access Technologies, Network Security, Society, Law & Ethics, Mobile Computing, Net Layer:Routing Protocol, Cyber Safety and Security
  9. Section B: Teaching Methodology: Child Development, Concept of Pedagogy, Theories, Inclusive Education, Experiential Pedagogy, Assessment & Evaluation, Curriculum Framework & Reforms, National Education Policy (NEP) 2020, Psychology, Teaching-Learning Process, Personality Development, Teaching Methods & Strategies, Learning and Motivation, Learners & Learning Process, Factors Affecting Teaching, Methods of Teaching, Nature, Objectives & Characteristics of Teaching, Teaching-Learning Aids & ICT Integration, Classroom Management & Communication, Evaluation, Assessment & Measurement, Curriculum & School Environment, Inclusive Education & Special Needs, Professional Development & Ethics
  10. Section B: Digital Electronics / Boolean Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Analog-Digital Conversion
  11. Section B: Operating Systems & Linux: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, File Management, Disc Scheduling, Unix OS, Linux OS, Distributed Systems, Windows OS
  12. Section B: Data Base Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, File Organization & Indexing, Transaction Management, Concurrency Control, Database Security & Authorization, Database Recovery, Data Warehousing & Mining
  13. Section B: Internet & Web Technologies: Website, Browser & Services, Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, HTML Basics, CSS, Emerging Technologies, JavaScript-Basics, .Net Programming, Electronic Data Interchange and E-Commerce, XML
  14. Section B: Computer Fundamentals, IT Basics & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer, Terms & Abbreviations, MS Office Applications, Instr Formats & Modes, Floating Point Rep
  15. Section B: Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  16. Section B: Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, extras, Fundamentals of Systems and Information Systems
  17. Section B: Design & Analysis of Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  18. Section B: Mathematics: Linear Algebra, Calculus, Trigonometry, Vectors, Set Theory, Functions, Relations, Propositional and Predicate Logic, Research Process Steps, Graph Theory
  19. Section B: Computer Graphics, Multimedia & Mobile Computing: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing, Multimedia
  20. Section B: Emerging Trends: Emerging Tech Trends, Knowledge Representation, Natural Language Processing
  21. DSSSB Previous Year Paper:
  22. Business Studies and Management: Business Communication, Business Organization and Management, Financial Accounting, Business Economics, Management Information System (MIS), Knowledge Management & New Economy
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture introduces Linux process scheduling, beginning with preemptive scheduling and time sharing before comparing the three main policies: SCHED_NORMAL (CFS/EEVDF), SCHED_FIFO, and SCHED_RR. It concludes by transitioning to process creation using the fork() system call.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The lecture opens with a slide titled 'Preemptive Scheduling, Time Sharing & Priority.' The instructor explains that Linux uses preemptive scheduling, meaning a running process can be temporarily interrupted by the scheduler. A numbered diagram illustrates this: step 1 shows 'P1 Running,' followed by red text stating 'Time slice expires / higher priority process arrives.' Step 2 shows the 'Scheduler' is triggered to make a new decision, and step 3 shows 'P2 Running.' The instructor uses a red pen to circle key terms like 'P1 Running' and underline the trigger conditions, emphasizing that this mechanism improves system responsiveness and multitasking.

  2. 2:00 – 5:00 02:00-05:00

    The lesson transitions to a new slide titled 'Time Sharing.' The instructor explains that CPU time is divided among multiple processes, with each process getting a small time interval called a 'time slice.' A Gantt chart visualizes this by showing the CPU switching between Process 1 (P1), Process 2 (P2), and Process 3 (P3) over increasing time intervals from T1 to T5. The instructor underlines key phrases such as 'small time interval' and 'After its time slice, the scheduler may switch the CPU to another process.' A color-coded legend distinguishes between the different processes, and a 'Key Point' callout box summarizes how time sharing allows multiple tasks to appear to run simultaneously.

  3. 5:00 – 10:00 05:00-10:00

    The lecture moves to priority-based scheduling, defining how the scheduler considers the priority of processes while making decisions. The instructor highlights that in Linux, a lower 'nice value' is associated with higher scheduling priority for normal processes. The text on screen states: 'Higher scheduling priority -> Greater chance/preference for CPU time.' The instructor underlines important phrases like 'priority of processes' and 'nice value.' This section bridges the gap between basic time sharing and the specific Linux scheduling policies, establishing that priority is a core factor in CPU allocation.

  4. 10:00 – 15:00 10:00-15:00

    The instructor presents a comprehensive overview of Linux scheduling policies, comparing SCHED_NORMAL (CFS/EEVDF), SCHED_FIFO, and SCHED_RR. Step-by-step flow diagrams illustrate each policy. For SCHED_NORMAL, the diagram shows a 'Fair Scheduler (CFS / EEVDF)' that provides fair CPU sharing. For SCHED_FIFO, the flow shows 'Pick Highest Priority (First In, First Out)' and running until a higher priority process arrives. For SCHED_RR, the diagram shows processes 'Run for Time Quantum (tq)' and asks 'Time Quantum Expired?' to determine if the process is preempted. The instructor uses red annotations to highlight key differences in CPU time sharing and priority handling across the three columns.

  5. 15:00 – 19:42 15:00-19:42

    The lecture continues detailing the flows of SCHED_NORMAL, SCHED_FIFO, and SCHED_RR, emphasizing that FIFO uses strict priority-based scheduling without preemption within the same priority, while RR operates on a round-robin basis. The final section transitions to a new topic: 'Process Creation using fork().' A slide explains that fork() is a system call used to create a new process in Linux. A summary table breaks down the return values of fork(), stating that '> 0: Returned to Parent -> value is Child's PID.' This marks the end of the scheduling policies discussion and the beginning of process creation concepts.

The lecture systematically builds understanding of Linux scheduling from fundamental concepts to specific policies. It starts by defining preemptive scheduling and time sharing, using diagrams and Gantt charts to visualize how the CPU is shared among processes. It then introduces priority as a decision factor, specifically mentioning the Linux 'nice value.' The core of the lecture compares the three main scheduling policies (SCHED_NORMAL, SCHED_FIFO, SCHED_RR) using flowcharts to show their distinct logic for CPU allocation. Finally, it transitions to process creation via fork(), linking scheduling decisions back to how processes are initially created. The progression moves from 'what' (preemption/time sharing) to 'how' (policies/flows) to 'where it starts' (fork).

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