Operating System (OS)

Operating System (OS)

1. What is an operating system?

   • An operating system is the most important software that runs on a computer
   • It manages the computer's memory, processes, and all of its software and hardware. It also allows you to communicate with the computer.
   • It manages all of the software and hardware on the computer.
   • There are many different programs running at the same time, and they all need to access your computer's central processing unit (CPU), memory, and storage.

2. Structure of OS

   • Kernel
     • It is a group of functions which are closely interlinked with the hardware. It is executed with the highest privilege available on the machine.
   • Management system of primary memory
     • It is performed by the MMU that allocates primary memory required by programs and the operating system itself, save to the mass memory storage areas temporarily used by programs (virtual memory).
   • Scheduler
     • It marks the time of execution of the various processes and ensures that each one of them to run for the required time.
   • File manager system
     • It is responsible to realize the requests of access to storage devices. Is used each time you access a file on disk, and in addition to providing the required data keeps track of open files, access permissions to the files.
   • Spooler
     • It receive programs from the print data and prints them in succession, allowing programs to continue without having to wait for the end of the print job.
   • User interface
     • It allows users to interact with the machine.
       • GUI
       • CLI

3. Types of operating systems

   • Microsoft Windows
     • Microsoft created the Windows operating system in the mid-1980s. Over the years, there have been many different versions of Windows, but the most recent ones are Windows 8 (released in 2012), Windows 7 (2009), and Windows Vista (2007).
     • You can choose from several different editions of Windows, such as Home Premium, Professional, and Ultimate.
   • Linux
     • Linux is a family of open-source operating systems, which means they can be modified and distributed by anyone around the world.
     • The advantages of Linux are that it is free, and there are many different distributions (or versions) you can choose from
   • Mac OS X
     • Mac OS is a line of operating systems created by Apple Inc
     • All of the recent versions are known as OS X and the specific versions include Mavericks Mountain Lion Lion and Snow Leopard
   • Mobile OS
     • The operating systems we've been talking about were designed to run on desktop or laptop computers. Mobile devices such as phones, tablet computers, and mp3 players are different from desktop and laptop computers, so they run operating systems that are designed specifically for mobile devices.