Operating system

Operating system

1. When you turn on your computer, it's nice to think that you're in control. There's the trusty computer mouse,which you can move anywhere on the screen, summoning up your music library or internet,and the real man behind the curtain handling the necessary tasks is the operating system.

   • Most desktop or laptop PCs come pre-loaded with Microsoft Windows.The operating system (OS) is the first thing loaded onto the computer. Without the operating system, a computer is useless.
   • More recently, operating systems have started to pop up in smaller computers as well. If you like to tinker with electronic devices, you're probably pleased that operating systems can now be found on many of the devices we use every day, from cell phone to wireless access points.
   • The purpose of an operating system is to organize and control hardware and software so that the device it lives in behaves in a flexible but predictable way.

2. What is an Operating System?

   • Not all computers have operating systems. The computer that controls the mirowave oven your kitchen, for example, doesn't need an operating system.
   • All desktop computers have operating systems. The most common are the Windows family of operating systems developed by microsoft, the Macintosh operating systems developed by Apple and the UNIX family of operating systems (which have been developed by a whole history of individuals, corporations and collaborators).
   • In any device that has an operating system, there's usually a way to make changes to how the device works. This is far from a happy accident; one of the reasons operating systems are made out of portable code rather than permanent physical circuits is so that they can be changed or modified without having to scrap the whole device
     • For a desktop computer user, this means you can add a new security update, system patch, new application or even an entirely new operating system rather than junk your computer and start again with a new one when you need to make a change.

3. How Operating Systems Work

   • The operating system controls every task your computer carries out and manages system resources.
   • At the simplest level, an operating system does two things:
     • 1. It manages the hardware and software resources of the system.
       • The first task, managing the hardware and software resources, is very important, as various programs and input methods compete for the attention of the central processing unit (CPU) and demand memory, storage and input/output (I/O) bandwidth for their own purposes.
     • 2. It provides a stable, consistent way for applications to deal with the hardware without having to know all the details of the hardware.
       • The second task, providing a consistent application interface, is especially important if there is to be more than one of a particular type of computer using the operating system, or if the hardware making up the computer is ever open to change

4. Types of Operating Systems

   • Real-time operating system
   • Single-user, single task
   • Single-user, multi-tasking
   • Multi-user

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