What is Operating System

Duration: 10 min

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Inside: a video lesson and guided study material.

Module outline

  1. HPSC Interview Preparation: Interview Preparation
  2. Python Language: 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
  3. Data Structure & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Sorting Algorithms, Minimum Spanning Trees, Time Complexity Analysis, Graph Theory, Shortest Path Algos
  4. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security
  5. Computer System & Organisation: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer
  6. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, SQL, File Organization & Indexing, Transaction Management, Concurrency Control
  7. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling
  8. Digital Logic & Circuits: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  9. Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Pushdown Automata & CFG, Turing Machines, Moore & Mealy Machines
  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. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Data Warehousing & Mining
  12. Introduction to Emerging Trends: Emerging Tech Trends
  13. Digital Society & Cyber Law: Society, Law & Ethics
  14. HPSC PGT Previous Year Paper:
  15. HPSC Assistant Professor Previous Year Paper:
  16. Live Sessions: HPSC Live Sessions, EMRS TGT/PGT Live Class
  17. Full Mock Test:
  18. HPSC PGT - MOCK Test Series:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture introduces the fundamental concept of an operating system (OS) as a core component of computer architecture. The instructor begins by defining the OS as an interface between the user and the core machine, using real-world analogies such as a car's steering wheel, a fan switch, and electronic device buttons to illustrate how an interface mediates interaction. The lecture then transitions to a formal definition, describing the OS as a program or system software that acts as an intermediary between users and hardware. A key role of the OS is presented as a resource manager or allocator, which controls and coordinates hardware resources like CPU time, memory, and system buses among various application programs. The lecture concludes by presenting an abstract view of a computer system, showing the layered architecture where hardware sits at the base, the OS acts as a platform above it, and user applications and compilers reside on top. Market share data for personal computer operating systems (Windows 82.7%, Mac 13.23%, Linux) and mobile phone operating systems (Android 87.5%, iOS 12.1%) is provided to contextualize real-world examples.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The lecture opens with a numbered agenda list on the left side of the screen, covering topics from 'What is Operating System' through 'Micro-Kernel approach' and 'System call.' The instructor introduces the core concept by displaying a slide titled 'What is Operating System,' which states that whatever is used as an interface between the user and the core machine is the OS. Real-world examples are shown, including a car steering wheel marked with red arrows, a ceiling fan next to a hand holding a remote circled in red, and a microwave oven. The instructor poses the guiding question of why an operating system is needed, answering that it enables everybody to use hardware in a convenient and efficient manner.

  2. 2:00 – 5:00 02:00-05:00

    The instructor continues explaining the interface concept using the same slide with the Ford steering wheel, ceiling fan remote, and electronic button panel. The lecture then transitions to a new slide titled 'Definition of Operating System,' which formally defines the OS as a program or system software that acts as an intermediary between the user and hardware. A cartoon boy and desktop computer are shown beside this definition. The instructor hand-draws a box labeled 'OS' with arrows connecting the user side to the computer, visually illustrating its intermediary role. This section bridges the intuitive interface analogy with a more technical software definition.

  3. 5:00 – 9:32 05:00-09:32

    The lecture introduces the OS as a 'Resource Manager/Allocator,' listing CPU time, memory, and system buses as managed resources, paired with a multi-armed manager graphic on a teal background. The slide states that the OS controls and coordinates the use of resources among various application programs. An 'Abstract View of a Computer System' is then presented, showing a layered architecture with Computer Hardware at the base, Operating System in the middle as a platform, and user applications and compilers above. The section concludes with market share examples: for personal computers, Microsoft Windows (82.7%), Mac (13.23%), and Linux; for mobile phones, Android (87.5%) and iOS (12.1%).

The lecture follows a clear pedagogical progression from intuitive analogy to formal definition to architectural role. It begins by grounding the abstract concept of an OS in familiar physical interfaces (steering wheel, fan switch), making the idea accessible before introducing technical terminology. The transition from 'interface' to 'program or system software' marks the shift from analogy to definition. The resource manager concept then explains the OS's functional purpose, while the layered architecture diagram provides a structural view of where the OS sits in the computer system. The market share data serves as a practical anchor, connecting theoretical concepts to real-world products students encounter daily. The teaching flow moves from what an OS is (interface), to how it is defined (system software), to what it does (resource management), and finally where it fits (layered architecture).

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