What is Operating system: Definition and 71 Discussions

An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources.
For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers.
The dominant general-purpose desktop operating system is Microsoft Windows with a market share of around 76.45%. macOS by Apple Inc. is in second place (17.72%), and the varieties of Linux are collectively in third place (1.73%). In the mobile sector (including smartphones and tablets), Android's share is up to 72% in the year 2020. According to third quarter 2016 data, Android's share on smartphones is dominant with 87.5 percent with also a growth rate of 10.3 percent per year, followed by Apple's iOS with 12.1 percent with per year decrease in market share of 5.2 percent, while other operating systems amount to just 0.3 percent. Linux distributions are dominant in the server and supercomputing sectors. Other specialized classes of operating systems (special-purpose operating systems)), such as embedded and real-time systems, exist for many applications. Security-focused operating systems also exist. Some operating systems have low system requirements (e.g. light-weight Linux distribution). Others may have higher system requirements.
Some operating systems require installation or may come pre-installed with purchased computers (OEM-installation), whereas others may run directly from media (i.e. live cd) or flash memory (i.e. USB stick).

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  1. W

    General Comments on (Dis)Advantages of changing from Win 10 to Win 11?

    Clearly there aren't clearcut answers. Still, any comments or arguments for/against? Security improvements would be a plus. I don't have any overly-specific use in mind, though I intend to do somewhat heavy machine learning with it.
  2. pairofstrings

    Inversion of Control: OS vs Software Development | Explained

    Hi. What is the difference between Inversion of Control in Operating system and IoC in Software Development? Thanks.
  3. fluidistic

    Questions about C++, pointers, OS and compiler memory allocation

    Sorry I don't have the codes right now. In C plus plus, when I declare an int, but don't assign any value to it, a space in memory is allocated for it. I can define a pointer and check its adress in hexadecimal, so far so good. I can run this program over and over and usually the int is...
  4. Brief-Wishbone

    Comp Sci Why is there so much bluff in computer science textbooks?

    I'm reading operating system concepts the dinosaur book as a linuxadmin to understand operating system concepts, but I find most stuffs there to be bluffly written. Total garbage. I'm currently reading about file system. Do have a look at it. It feels like authors are intentionally wanting to...
  5. shivajikobardan

    Looking for learning resources for Computer Operating Systems

    TL;DR Summary: operating systems books and courses recommendations. I've to get FE exam to get licensed as an engineer in Nepal. I want to learn everything properly because I feel I didn't learn to the extent that I could in college. My first hitlist is operating system and Database Management...
  6. A

    Comp Sci For which of the following purposes is the Banker’s algorithm used?

    I am new to the operating system and I want to know, Is it right Banker's Algorithm is mainly used to prevent deadlock? I picked this question from https://www.interviewbit.com/operating-system-mcq/ and I think it is also used for Solving deadlock, Can anyone know, Is this right?
  7. Y

    C/C++ Is Learning C and C++ Essential for Understanding Operating Systems?

    Hi I want to know a little more about learning operating system. My grandson told me he is taking a class in operating system and the teacher use C and C++ mostly. He and his friends are in trouble because his school is Java based, none of them really know C++ and C. Is Operating system...
  8. S

    Comp Sci The systems which allow only one process execution at a time, are what?

    MY CONFUSION (WHICH IS WHAT THIS POST IS ABOUT): * The reason why c is not the correct answer is because unitasking just means a system that has one simulatenous user, right? In other words, a unitasking system can still be a multiprogramming system, such that one simultaneous user has the...
  9. Operating Systems (NPTEL):- Lecture 01: Introduction to UNIX System Calls Part - 1

    Operating Systems (NPTEL):- Lecture 01: Introduction to UNIX System Calls Part - 1

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  10. Operating Systems (NPTEL):- Lecture 02: Introduction to UNIX System Calls Part - 2

    Operating Systems (NPTEL):- Lecture 02: Introduction to UNIX System Calls Part - 2

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  11. Operating Systems (NPTEL):- Lecture 03: Threads, Address Spaces, Filesystem Devices

    Operating Systems (NPTEL):- Lecture 03: Threads, Address Spaces, Filesystem Devices

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  12. Operating Systems (NPTEL):- Lecture 04: PC Architecture

    Operating Systems (NPTEL):- Lecture 04: PC Architecture

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  13. Operating Systems (NPTEL):- Lecture 05: x86 Instruction Set, GCC Calling Conventions

    Operating Systems (NPTEL):- Lecture 05: x86 Instruction Set, GCC Calling Conventions

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  14. Operating Systems (NPTEL):- Lecture 06: Physical Memory Map, I/O, Segmentation

    Operating Systems (NPTEL):- Lecture 06: Physical Memory Map, I/O, Segmentation

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  15. Operating Systems (NPTEL):- Lecture 07: Segmentation, Trap Handling

    Operating Systems (NPTEL):- Lecture 07: Segmentation, Trap Handling

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  16. Operating Systems (NPTEL):- Lecture 08: Traps, Trap Handlers

    Operating Systems (NPTEL):- Lecture 08: Traps, Trap Handlers

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  17. Operating Systems (NPTEL):- Lecture 09: Kernel Data Structures, Memory Management

    Operating Systems (NPTEL):- Lecture 09: Kernel Data Structures, Memory Management

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  18. Operating Systems (NPTEL):- Lecture 10: Segmentation Review, Introduction to Paging

    Operating Systems (NPTEL):- Lecture 10: Segmentation Review, Introduction to Paging

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike
  19. Operating Systems (NPTEL):- Lecture 11: Paging

    Operating Systems (NPTEL):- Lecture 11: Paging

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  20. Operating Systems (NPTEL):- Lecture 12: Process Address Spaces Using Paging

    Operating Systems (NPTEL):- Lecture 12: Process Address Spaces Using Paging

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed
  21. Operating Systems (NPTEL):- Lecture 13: Translation Lookaside Buffer, Large Pages, Boot Sector

    Operating Systems (NPTEL):- Lecture 13: Translation Lookaside Buffer, Large Pages, Boot Sector

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  22. Operating Systems (NPTEL):- Lecture 14: Loading the kernel, Initializing the Page table

    Operating Systems (NPTEL):- Lecture 14: Loading the kernel, Initializing the Page table

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  23. Operating Systems (NPTEL):- Lecture 15: Setting up page tables for user processes

    Operating Systems (NPTEL):- Lecture 15: Setting up page tables for user processes

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  24. Operating Systems (NPTEL):- Lecture 16: Processes in action

    Operating Systems (NPTEL):- Lecture 16: Processes in action

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  25. Operating Systems (NPTEL):- Lecture 17: Process structure, Context Switching

    Operating Systems (NPTEL):- Lecture 17: Process structure, Context Switching

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  26. Operating Systems (NPTEL):- Lecture 18: Process Kernel stack, Scheduler, Fork,Context-Switch, etc.

    Operating Systems (NPTEL):- Lecture 18: Process Kernel stack, Scheduler, Fork,Context-Switch, etc.

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  27. Operating Systems (NPTEL):- Lecture 19: Creating the first process

    Operating Systems (NPTEL):- Lecture 19: Creating the first process

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  28. Operating Systems (NPTEL):- Lecture 20: Handling User Pointers, Concurrency

    Operating Systems (NPTEL):- Lecture 20: Handling User Pointers, Concurrency

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  29. Operating Systems (NPTEL):- Lecture 21: Locking

    Operating Systems (NPTEL):- Lecture 21: Locking

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  30. Operating Systems (NPTEL):- Lecture 22: Fine-grained Locking and its challenges

    Operating Systems (NPTEL):- Lecture 22: Fine-grained Locking and its challenges

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  31. Operating Systems (NPTEL):- Lecture 23: Locking variations

    Operating Systems (NPTEL):- Lecture 23: Locking variations

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  32. Operating Systems (NPTEL):- Lecture 24: Condition variables

    Operating Systems (NPTEL):- Lecture 24: Condition variables

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  33. Operating Systems (NPTEL):- Lecture 25: Multiple producer, multiple consumer queue; semaphores; etc.

    Operating Systems (NPTEL):- Lecture 25: Multiple producer, multiple consumer queue; semaphores; etc.

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  34. Operating Systems (NPTEL):- Lecture 26: Transcations and lock-free primitives read/write locks

    Operating Systems (NPTEL):- Lecture 26: Transcations and lock-free primitives read/write locks

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  35. Operating Systems (NPTEL):- Lecture 27: Synchronization in xv6: acquire/release, sleep/wakeup, etc.

    Operating Systems (NPTEL):- Lecture 27: Synchronization in xv6: acquire/release, sleep/wakeup, etc.

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  36. Operating Systems (NPTEL):- Lecture 28: Synchronization in xv6: kill, IDE device driver; Demand Pagi

    Operating Systems (NPTEL):- Lecture 28: Synchronization in xv6: kill, IDE device driver; Demand Pagi

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  37. Operating Systems (NPTEL):- Lecture 29: Demand Paging; Introduction to Page Replacement

    Operating Systems (NPTEL):- Lecture 29: Demand Paging; Introduction to Page Replacement

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  38. Operating Systems (NPTEL):- Lecture 30: Page Replacement, Thrashing

    Operating Systems (NPTEL):- Lecture 30: Page Replacement, Thrashing

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  39. Operating Systems (NPTEL):- Lecture 31: Storage Devices, File system Interfaces

    Operating Systems (NPTEL):- Lecture 31: Storage Devices, File system Interfaces

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  40. Operating Systems (NPTEL):- Lecture 32: File System Implementation

    Operating Systems (NPTEL):- Lecture 32: File System Implementation

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  41. Operating Systems (NPTEL):- Lecture 33: File System Operation

    Operating Systems (NPTEL):- Lecture 33: File System Operation

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  42. Operating Systems (NPTEL):- Lecture 34: Crash Recovery and Logging

    Operating Systems (NPTEL):- Lecture 34: Crash Recovery and Logging

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  43. Operating Systems (NPTEL):- Lecture 35: Logging in Linux ext3 filesystem

    Operating Systems (NPTEL):- Lecture 35: Logging in Linux ext3 filesystem

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  44. Operating Systems (NPTEL):- Lecture 36: Protection and Security

    Operating Systems (NPTEL):- Lecture 36: Protection and Security

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  45. Operating Systems (NPTEL):- Lecture 37: Scheduling Policies

    Operating Systems (NPTEL):- Lecture 37: Scheduling Policies

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  46. Operating Systems (NPTEL):- Lecture 38: Lock-free multiprocessor coordination, Read-Copy-Update

    Operating Systems (NPTEL):- Lecture 38: Lock-free multiprocessor coordination, Read-Copy-Update

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  47. Operating Systems (NPTEL):- Lecture 39: Microkernel, Exokernel, Multikernel

    Operating Systems (NPTEL):- Lecture 39: Microkernel, Exokernel, Multikernel

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  48. Operating Systems (NPTEL):- Lecture 40: Virtualization, Cloud Computing, Technology Trends

    Operating Systems (NPTEL):- Lecture 40: Virtualization, Cloud Computing, Technology Trends

    Instructor: Prof. Sorav Bansal Course Website: https://nptel.ac.in/courses/106/102/106102132/ Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA
  49. pairofstrings

    Operating system concepts in an app by Linux System calls

    Before I begin learning what System Calls, Kernel, and Operating System is, I want to confirm that Operating System concepts like Multi-threading, Concurrency, Parallelism, Scheduling, Memory Management, Process Management, Network Management, Device Drivers can be implemented by using Linux...
  50. pairofstrings

    Conventional Computers vs Artificially Intelligent Computers

    Hello. A conventional computer has an Operating System that has Process, Memory, Scheduler, Input/Output and Files. My question is: What the Operating System of Artificially Intelligent Computers will have?Thank you.
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