Schedulers

Duration: 11 min

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Inside: a video lesson and guided study material.

Module outline

  1. About the course: About the Course
  2. Mathematical Aptitude: संख्या पद्धति / Number System, महत्तम समापवर्तक और लघुत्तम समापवर्त्य / HCF and LCM, Divisibility Rules, प्रतिशत / Percentage, अनुपात और समानुपात / Ratio and Proportion, औसत / Average, लाभ, हानि और बट्टा / Profit, Loss and Discount, समय और कार्य / Time and Work, घन क्षेत्रमिति / Solid Mensuration, साधारण और चक्रवृद्धि ब्याज / Simple and Compound Interest, समय, चाल और दूरी / Time, Speed and Distance, Age Problems, मिश्रण और एलिगेशन / Mixture and Alligation, Algebra, सरलीकरण, घातांक और करणी / Simplification, Indices and Surds, Pipe and Cistern, Trigonometry, Statistics, आँकड़ा निर्वचन / Data Interpretation, Arithmetic, समुच्चय, संबंध, फलन और विविक्त गणित / Sets, Relations, Functions and Discrete Mathematics, संख्या पद्धति और संख्या सिद्धांत / Number Systems and Number Theory, निर्देशांक ज्यामिति, सदिश और त्रिविमीय ज्यामिति / Coordinate Geometry, Vectors and 3D Geometry, बहुपद, समीकरण और सम्मिश्र संख्याएँ / Polynomials, Equations and Complex Numbers
  3. Logical Reasoning: श्रेणी / Series, कूट लेखन एवं कूट वाचन / Coding-Decoding, सादृश्यता एवं वर्गीकरण / Analogy and Classification, रक्त संबंध / Blood Relations, दिशा एवं दूरी / Direction and Distance, क्रम एवं रैंकिंग / Order and Ranking, अशाब्दिक तर्क / Non-Verbal Reasoning, बैठक व्यवस्था एवं पहेलियाँ / Seating Arrangement and Puzzles, Syllogisms, वेन आरेख, न्याय वाक्य एवं असमानता / Venn Diagrams, Syllogism and Inequalities, गणितीय संक्रियाएँ एवं लुप्त संख्या / Mathematical Operations and Missing Numbers, वर्णमाला एवं संख्या परीक्षण / Alphabet and Number Test, कथन आधारित तार्किक विवेचन / Statement-Based Reasoning, Analytical Reasoning (Counting Figures Reasoning), घन, पासा एवं आकृतियों की गिनती / Cubes, Dice and Figure Counting, कैलेंडर एवं घड़ी / Calendar and Clock, Clock
  4. General Knowledge: वैज्ञानिक उपलब्धियाँ और अनुसंधान / Scientific Achievements and Research, Chemistry, Biology, History, Geography, Polity, Indian Economy, समसामयिकी / Current Affairs, Static General Knowledge
  5. Art of Teaching: शिक्षण-अधिगम प्रक्रिया एवं कक्षा प्रबंधन / Teaching-Learning Process and Classroom Management, Learners & Learning Process, Factors Affecting Teaching, शिक्षण विधियाँ एवं उपागम / Teaching Methods and Approaches, सूक्ष्म शिक्षण एवं कक्षा संप्रेषण / Microteaching and Classroom Communication, शिक्षण सहायक सामग्री एवं शैक्षिक तकनीकी / Teaching Aids and Educational Technology, आकलन एवं मूल्यांकन / Assessment and Evaluation, शिक्षक: गुण, व्यावसायिक नैतिकता एवं विकास / Teacher: Qualities, Professional Ethics and Development, शैक्षिक नीतियाँ, अधिनियम एवं प्रशासन / Educational Policies, Acts and Administration, पाठ्यचर्या, कला एवं सह-शैक्षिक क्षेत्र / Curriculum, Arts and Co-curricular Areas, निर्देशन एवं परामर्श / Guidance and Counselling, दिव्यांग बच्चों की शिक्षा / Education of Children with Disabilities, Micro-Teaching & Teaching Skills, पाठ योजना / Lesson Planning
  6. Environmental Science: Environment
  7. Unit 1 | Digital Electronics: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  8. Unit 2 | COA: Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations, Programming the Basic Computer
  9. Unit 3 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  10. Unit 3 | Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  11. Unit 4 | Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  12. Unit 5 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management
  13. Unit 6 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Transaction Management, Concurrency Control
  14. Unit 7 | 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
  15. Unit 8 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  16. Unit 9 | Object Oriented Programming: OOPS with C++
  17. Unit 10 | Web Development: HTML Basics, CSS, JavaScript-Basics, XML, Node.js
  18. Unit 11 | 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
  19. Unit 12 | IoT: Emerging Tech Trends, Cloud Computing, कंप्यूटर नेटवर्क / Computer Networks
  20. Unit 13 | Artificial Intelligence: Approaches to AI, Search Algorithms, Game Playing, Knowledge Representation, Natural Language Processing, Artificial Neural Networks, Genetic Algorithms
  21. Unit 14 | E-Commerce: Electronic Data Interchange and E-Commerce, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Physical Security and Cryptography Basics, Cyber Safety and Security
  22. Unit 15 | Multimedia: Multimedia
  23. Unit 16 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis, DSA using Python
  24. Full Length Mock Tests — General Paper:
  25. Full Length Mock Tests — Computer Science (Paper II):
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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