Operating Systems

What is operating system?

The most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

For large systems, the operating system has even greater responsibilities and powers. It is like a traffic cop it makes sure that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system.

Operating systems can be classified as follows:
  • 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.


Microsoft Windows is a range of closed source proprietary commercial operating environments for personal computers and also servers. The range was first introduced by Microsoft in 1985 and eventually has come to dominate the world personal computer market. All recent .....

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Apple's newest name for its operating system (in fact, it stands for Macintosh Operating System). Previously, Apple referred to its OS as simply "System x" (where "x" is the version number). The Mac OS X has a layered structure with a foundation layer (BSD Unix) named Darwin ...

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Linux is a free Unix-type operating system originally created by Linus Torvalds with the assistance of developers around the world. Developed under the GNU General Public License, the source code for Linux is freely available to everyone.

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