Schedulers

Duration: 11 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 educational video provides a detailed lecture on the concept of schedulers within Operating Systems, specifically focusing on the different types of schedulers and their roles in process management. The instructor begins by defining schedulers as the mechanism that selects processes from various queues for execution. The lecture progresses to distinguish between Long-term, Short-term, and Medium-term schedulers, explaining their specific functions such as admission control, CPU allocation, and swapping. Visual aids, including diagrams of process states and flowcharts, are used to illustrate how processes migrate between main memory and secondary storage. The session concludes with an explanation of the Dispatcher module, highlighting its critical role in context switching and the concept of dispatch latency.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a slide titled 'Schedulers'. The instructor reads the definition: 'A process migrates among the various scheduling queues throughout its lifetime. The operating system must select, for scheduling purposes, processes from these queues in some fashion. The selection process is carried out by the appropriate scheduler.' He then introduces the 'Types of Schedulers' section. The first type discussed is the 'Long Term Schedulers (LTS)/Spooler'. The slide text explains that in a multiprogramming OS, more processes are submitted than can be executed immediately. Consequently, these processes are 'spooled to a mass-storage device (typically a disk), where they are kept for later execution.' The instructor emphasizes that the long-term scheduler, also called the job scheduler, selects processes from this pool and loads them into memory for execution.

  2. 2:00 – 5:00 02:00-05:00

    The instructor elaborates on the Long Term Scheduler using a hand-drawn diagram. He sketches a box labeled 'M' representing Main Memory and another labeled 'SM' for Secondary Memory, drawing an arrow to show the flow of processes. He explains that the LTS controls the degree of multiprogramming by bringing processes into main memory. He then transitions to the 'Short Term Scheduler (STS)'. The slide text states: 'The short-term scheduler, or CPU scheduler, selects from among the processes that are ready to execute and allocates the CPU to one of them.' The instructor highlights that this scheduler is invoked frequently, unlike the long-term scheduler, to manage CPU allocation efficiently among ready processes.

  3. 5:00 – 10:00 05:00-10:00

    The lecture shifts to the 'Degree of Multiprogramming', defined on the slide as 'The number of processes in memory'. The text notes that the long-term scheduler controls this degree. A key concept presented is stability: 'If the degree of multiprogramming is stable, then the average rate of process creation must be equal to the average departure rate of processes leaving the system.' The instructor draws a graph with 'n' on the y-axis to visualize this stability. He then introduces the 'Medium-term scheduler', explaining its role in swapping. The slide text reads: 'The key idea behind a medium-term scheduler is that sometimes it can be advantageous to remove a process from memory... and thus reduce the degree of multiprogramming.' He explains that this process is called swapping, where a process is swapped out to disk and later swapped back in to continue execution. A diagram shows the flow between 'partially executed swapped-out processes', 'ready queue', 'CPU', and 'I/O'.

  4. 10:00 – 11:14 10:00-11:14

    The final section covers the 'Dispatcher'. The slide defines it as 'the module that gives control of the CPU to the process selected by the short-term scheduler.' The instructor details the functions involved: 'Switching context, switching to user mode, jumping to the proper location in the user program to restart that program.' He stresses that the dispatcher must be fast because it is invoked during every process switch. The concept of 'dispatch latency' is introduced, defined as 'The time it takes for the dispatcher to stop one process and start another running.' The instructor draws a diagram illustrating context switching between two processes to visualize this rapid transfer of control.

The video effectively structures the complex topic of process scheduling by breaking it down into distinct functional modules. It establishes a clear hierarchy starting with the Long-term scheduler for admission, moving to the Short-term scheduler for CPU allocation, and the Medium-term scheduler for memory management via swapping. The lesson culminates with the Dispatcher, the low-level mechanism that executes the actual context switch. This progression helps students understand the lifecycle of a process and the specific OS components responsible for managing its execution state and resource allocation.

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