¿What is a OS?

¿What is a OS?

1. OS is a abbreviation of operating system. An operating system is a software program that enables the computer hardware to communicate and operate with the computer software, so is the most important program that runs on a computer. To explain better, every general-purpose computer must have an operating system to run other programs ( called applications or application programs ). Without a computer operating system, a computer and software programs would be useless.

   • ¿How it works?
     • The operating system acts as an interface between an application and the hardware. The user interacts with the hardware from "the other side". The operating system is a set of services which simplifies development of applications. Executing a program involves the creation of a process by the operating system. The kernel creates a process by assigning memory and other resources, establishing a priority for the process, loading program code into memory, and executing the program. The program then interacts with the user and/or other devices performing its intended function.
   • Types of OS.
     • Below is a basic list of the types of operating systems and some example of an operating system that fall into each of the types.
       • GUI.
         • Graphical User Interface, or GUI (pronounced "gooey"). A GUI lets you use your mouse to click on icons, buttons, and menus, and everything is clearly displayed on the screen using a combination of graphics and text. Each operating system's GUI has a different look and feel, so if you switch to a different operating system it may seem unfamiliar at first. Example: Apple System 7 and Mac OS X.
       • Real-time
         • Real time system is defines as a data processing system in which the time interval required to process and respond to inputs is so small that it controls the environment. Real time processing is always on line whereas on line system need not be real time. The time taken by the system to respond to an input and display of required updated information is termed as response time. So in this method response time is very less as compared to the online processing. There are two types; Hard real - time systems and Soft real - time systems.
       • Multi-user
         • A multi-user operating system allows for multiple users to use the same computer at the same time and different times. Example: Linux.
       • Multiprocessing.
         • An operating system capable of supporting and utilizing more than one computer processor. Example: Windows XP.
       • Multi-tasking.
         • A multi-tasking operating system allows more than one program to be running at the same time, from the point of view of human time scales. Example : Unix.
       • Distributed.
         • Distributed systems use multiple central processors to serve multiple real time application and multiple users. Data processing jobs are distributed among the processors accordingly to which one can perform each job most efficiently. Example : Amoeba.
       • Embedded.
         • The operating systems designed for being used in embedded computer systems are known as embedded operating systems. They are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources. They are very compact and extremely efficient by design. Example : Windows CE.
   • OS functions.
     • 1) Interprate the commands executed by the user.
       • 2) To handle disk input/output settings.
         • 3) Loaded in the memory at bootup and remain in the memory at all time.
           • 4) To provid the OS with the machanism in order to see the additional memory.
             • 5) Used to access the high memory area.
               • 6) It allows the rest of the OS and its programs to interact directry with the system hardware and the system BIOS.
                 • 7) It sets particular values corresponding to the windows environment.
                   • 8) Environment managemnt.
                     • 9) Used to run particular programs during startup.
                       • 10) File management- it helps in creation, saving and deletion of files.
   • Os developments.
     • The first systems (1945-1955) were large machines operated from the master console by programmers. Over the next decade (1955-1965) were carried out 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 computer equipped with an accelerator Commodore Amiga Video Toaster was capable of producing effects compared to dedicated systems costing three times .