Operating System (Pro. choosing)


Operating SystemsOS

An operating System (OS) is an intermediary between users and computer hardware. It provides users an environment in which a user can execute programs conveniently and efficiently.

In technical terms, It is a software which manages hardware. An operating System controls the allocation of resources and services such as memory, processors, devices and information.

Following are some of important functions of an operating System:

  • Memory Management
  • Processor Management
  • Device Management
  • File Management
  • Security
  • Control over system performance
  • Job accounting
  • Error detecting aids
  • Coordination between other software and users

Memory Management

Memory management refers to management of Primary Memory or Main Memory. Main memory is a large array of words or bytes where each word or byte has its own address.

Main memory provides a fast storage that can be access directly by the CPU. So for a program to be executed, it must in the main memory. Operating System does the following activities for memory management.

  • Keeps tracks of primary memory i.e. what part of it are in use by whom, what part are not in use.
  • In multiprogramming, OS decides which process will get memory when and how much.
  • Allocates the memory when the process requests it to do so.
  • De-allocates the memory when the process no longer needs it or has been terminated.

Processor Management

In multiprogramming environment, OS decides which process gets the processor when and how much time. This function is called process scheduling. Operating System does the following activities for processor management.

  • Keeps tracks of processor and status of process. Program responsible for this task is known as traffic controller.
  • Allocates the processor(CPU) to a process.
  • De-allocates processor when processor is no longer required.

Device Management

OS manages device communication via their respective drivers. Operating System does the following activities for device management.

  • Keeps tracks of all devices. Program responsible for this task is known as the I/O controller.
  • Decides which process gets the device when and for how much time.
  • Allocates the device in the efficient way.
  • De-allocates devices.

File Management

A file system is normally organized into directories for easy navigation and usage. These directories may contain files and other directions. Operating System does the following activities for file management.

  • Keeps track of information, location, uses, status etc. The collective facilities are often known as file system.
  • Decides who gets the resources.
  • Allocates the resources.
  • De-allocates the resources.

Other Important Activities

Following are some of the important activities that Operating System does.

  • Security— By means of password and similar other techniques, preventing unauthorized access to programs and data.
  • Control over system performance— Recording delays between request for a service and response from the system.
  • Job accounting— Keeping track of time and resources used by various jobs and users.
  • Error detecting aids— Production of dumps, traces, error messages and other debugging and error detecting aids.
  • Coordination between other softwares and users— Coordination and assignment of compilers, interpreters, assemblers and other software to the various users of the computer systems.

The Classification of Operating systems

  • Multi-user: Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.
  • Multiprocessing : Supports running a program on more than one CPU.
  • Multitasking : Allows more than one program to run concurrently.
  • Multithreading : Allows different parts of a single program to run concurrently.
  • Real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.

Operating systems provide a software platform on top of which other programs, called application programs, can run. The application programs must be written to run on top of a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are Mac OS X, and Windows, but others are available, such as Linux.


The GUI-based OS was introduced in1985 and has been released in many versions since then, as described below.

Microsoft got its start with the partnership of Bill Gates and Paul Allen in 1975. Gates and Allen co-developed Xenix (a version of Unix) and also collaborated on a BASIC interpreter for the Altair 8800. The company was incorporated in 1981.

2001: Windows XP

Windows XP was released as the first NT-based system with a version aimed squarely at the home user. XP was rated highly by both users and critics. The system improved Windows’ appearance with themes, and offered a stable platform. XP was also the end of gaming in DOS, for all intents and purposes. Direct X enabled features in 3D gaming that OpenGL had trouble keeping up with at times. Future versions of Windows would be compared to XP for gaming performance for some time. XP offered the first Windows support for 64-bit computing. However, 64-bit computing was not very well supported in XP, and also lacked drivers or much software to run.


As it turned out, Windows XP was one of the most popular versions. In combination with the unpopularity of the upcoming Vista system, that would eventually lead to update-related problems.

2006: Windows Vista


Windows Vista was a highly hyped release that spent a lot of developmental and computer resources on appearance. The dedication of resources might have resulted from the fact that XP was starting to look archaic in comparison to Mac OS. Vista had interesting visual effects but was slow to start and run. The 32-bit version in particular didn’t enable enough RAM for the memory-hungry OS to operate quickly. Users still timid to embrace 64-bit missed out on a marginally better experience, offered along with investment in more than 4GB of RAM. Gamers found the added exclusive features in Direct X 10 only mildly tempting compared to XP’s speed. Licensing rights and Windows activation became stricter, while user control of internal workings became less accessible. Microsoft lost market share in this time to Apple and Linux variants alike. Vista’s flaws — coupled with the fact that many older computers lacked the resources to run the system — led to many home and business users staying with XP rather than updating. That situation was to become problematic when Microsoft announced that XP end of life would occur in April 2014.


2009: Windows 7

Windows 7 is built on the Vista kernel. Windows 7 had the visuals of Vista with better start up and program speed. It was easier on memory and more reliable. To many end users, the biggest changes between Vista and Windows 7 are faster boot times, new user interfaces and the addition of Internet Explorer 8.


The system plays games almost as well as XP. With true 64-bit support and an increasing separation in Direct X features that were not implemented in XP, that small performance difference benefit was further eroded. Windows 7 became the most used operating system on the Internet and also the most used for PC gaming.

2012: Windows 8


Windows 8 was released with a number of enhancements and the new Metro UI. Windows 8 takes better advantage of multi-core processing, solid state drives (SSD), touch screens and other alternate input methods. However users found it awkward, like switching between an interface made for a touch screen and one made for a mouse — with neither one entirely suited to the purpose. Generally Windows 7 retained market leadership. Even after Microsoft’s UI and other updates in 8.1, Windows 8 trailed not just 7 but XP in user numbers into 2014.

2015: Windows 10


Microsoft announced Windows 10 in September 2014, skipping Windows 9. Version 10 includes the start menu, which was absent from Windows 8. A responsive design feature called Continuum adapts the interface depending on whether the touch screen or keyboard and mouse are being used for input. New features like an on-screen back button simplify touch input. The OS is designed to have a consistent interface across user devices including PCs, laptops, phones and tablets.


Windows 10 beefs up Snap, the function that lets you quickly arrange apps side by side, with a new quadrant layout that lets you split your display up among up to four apps. There’s also support for multiple virtual desktops (finally), so you can keep all your work apps in one place and quickly slide back to the desktop with your blogs and Reddit once your boss walks away. And then there’s the task view button that lives on the taskbar. Click it, and you’ll get a quick look at all of your open files, windows, and desktops.


As if bringing the Start Menu back weren’t enough, Microsoft has built its personal voice assistant Cortana right in. Even if you’re already using Google Now or Siri, having Cortana on your desktop can be handy. You can perform web searches to get many of the same quick answers by simply pressing the Win key and typing a question like “How many ounces are in a cup” or “What’s the weather like?”


Being able to run a few apps at once is the great benefit of an operating system like Windows. Running too many, though, can get overwhelming. Now, Microsoft is finally adding the ability to create and manage multiple desktops. You can add new desktops, quickly move windows between them, and jump between desktops by pressing Win-Tab. This may not be all that useful for average users, but those of us who do a lot of work with our machines will appreciate the feature.

Wi-Fi Sense

I’d be remiss if I didn’t mention Wi-Fi Sense. While technically not a new feature (it’s part of Windows Phone 8.1) its presence in Windows 10 should’ve been a welcome addition: Wi-Fi Sense connects your devices to trusted Wi-Fi hotspots.

I love the idea. Automatically sharing Wi-Fi credentials with my friends would remove much of the hassle of most social gatherings, when people just want to jump on my Wi-Fi network. And — this part is key — Wi-Fi Sense doesn’t share your actual password, so it theoretically eases a social transaction (the sharing of Wi-Fi connectivity) without necessarily compromising my network security.

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