OS - Operating System

OS - Operating System

1. What is a OS?

   • An operating system (OS) is software that manages computer hardware and software resources and provides common services for computer programs.And it is the most important program that runs on a computer.An example of an Operating System is Windows, Linux, and Macintosh.

2. How it works?

   • The operating system defines our computing experience. It's the first software we see when we turn on the computer, and the last software we see when the computer is turned off. It's the software that enables all the programs we use. The operating system organizes and controls the hardware on our desks and in our hands, yet most users can't say with any certainty precisely what it is that the operating system does.

3. Types of OS.

   • Real-time
     • A real-time operating system is a multitasking operating system that aims at executing real-time applications. Real-time operating systems often use specialized scheduling algorithms so that they can achieve a deterministic nature of behavior.
   • Multi-user
     • A multi-user operating system allows multiple users to access a computer system at the same time. Time-sharing systems and Internet servers can be classified as multi-user systems as they enable multiple-user access to a computer through the sharing of time
   • single-tasking
     • A single-tasking system has only one running program.
   • Distributed
     • A distributed operating system manages a group of independent computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine. When computers in a group work in cooperation, they make a distributed system.
   • Templated
     • n an o/s, distributed and cloud computing context, templating refers to creating a single virtual machine image as a guest operating system, then saving it as a tool for multiple running virtual machines
   • Embedded
     • Embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy.

4. OS developments.

   • The first systems (1945-1955) were large machines operated from the console teacher by programmers. Over the next decade (1955-1965) were carried After advances in hardware: card readers, printers, magnetic tapes, etc. This in turn led to a breakthrough in software compilers, assemblers, loaders, device drivers, etc. In the late 1980s, a Commodore Amiga computer equipped with an accelerating Video Toaster was able produce effects compared to dedicated systems costing three times. a Video Toaster with Lightwave helped produce many TV shows and movies, including Babylon 5, SeaQuest DSV and Terminator 2 are included.

5. OS functions.

   • 4) to interprate the commands executed by the user.
   • 7) to handle disk input/output settings.
   • 3) loaded in the memory at bootup and remain in the memory at all time.
   • 2) to provid the OS with the machanism in order to see the additional memory.
   • 6) used to access the high memory area. (himem.sys )
   • 1) it allows the rest of the OS and its programs to interact directry with the system hardware and the system BIOS.
   • 5) it sets particular values corresponding to the windows environment.
   • 8) used to run particular programs during startup.