Operating System (OS)

Operating System (OS)

1. What is a OS ?

   • Operating System (OS) is software that manages computer hardware and software resources and provides common services for computer programs.

2. How it works ?

   • Operating System perform basics 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.

3. Types of OS

   • There are 5 types
     • 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.
         • For example : Windows 95, Windows 2000.
     • Multiprocessing
       • Supports running a program on more than one CPU.
     • Multitasking
       • Allows more than one program to run concurrently
         • For example : Windows 9x support multitasking.
     • Multithreading
       • Allows different parts of a single program to run concurrently.
     • Real Time
       • Responds to input instantly.
         • For example : Windows CE, OS-9, Sysmbian and LynxOS

4. Operating System Funtions

5. Operating System Development

   • At the end of the decade of 1940, with what it might consider to be the appearance of the first generation of computers, did not operating systems exist.
     • At the beginning of the 50s in order to facilitate the interaction between(among) person and computer, the operating systems do a discreet appearance.
       • During the 60s and 70s there were remarkable changes in several fields of the computer science, as the appearance of the integrated circuit, the majority orientated to continuing increasing the potential of the computers and of the operating systems. UNIX and Multics arise.
         • During the 80s with the integration of the large-scale circuits and chips that were containing thousands of transistors began the boom of computers. -Mac OS-MS DOS

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