Operating System is a type of system software,which has a set of programs containing instructions that functions to control most or all of the actions among hardware resources.Functions of operating system varies from Starting and shutting down a computer,providing a user interface,managing programs,managing memory,coordinating tasks,establishing an internet connection,providing file management and other utilities,and automatically updating itself and certain utility programs.There are some operating system which allows its users to control a network and administer security.An operating system can run from an optical disc or flash memory mobile media,in common cases,the OS is installed and resides on the computer’s hard disk.In smartphones,the Operating system reside on a ROM chip.
Sizes of operating system varies in computers because they are written to run on specific type of computer.Mainframe computers does not use the same operating system as a personal computer.when purchasing an application software,one should be sure that it works with the operating system installed on the computer or mobile device.The operating system that a computer uses could also be refered to as the platform.A cross -platform program is one that runs the same on multiple operating systems.The operating system handles many functions automatically,without requiring any instructions from the user.Functions of Operating system includes the following.
Starting and shorting down a computer: The process of starting or restarting of a computer is refered to as Booting.there are two types of booting,which are warm boot and cold boot.A typical illustration of warm boot is turning on a computer that has been powered off completely,while warm boot is the process of using the operating system to restart a computer.A warm boot properly closes any running processes and programs,but it does not save any unsaved work.With windows you can perform a warm boot by clicking on the start button on the task bar ,clicking the arrow next to the shut down button on the start menu,and then clicking restart.When you install a new software,often an on-screen prompt instructs you to restart the computer.In this case a warn boot is most appropriate to use.Each time you boot a computer,the kernel and other frequently used operating system instructions are loaded ,copied,from storage into the computer’s memory.The kernel manages memory and devices,maintains the computer’s clock,starts programs,data and information.
Providing a Graphic user Interface:Computer users work with a Graphical user interface(GUI),this controls how you enter data and instructions and hoe information is displayed on the screen.Most recent GUI operating systems incorporate futures similar to those of a web browser,e.g links and navigation buttons.some GUI operating systems provide access to command -line interface.Windows for example, offers two different GUIs,depending on the hardware configuration.computers with less than 1 GB of RAM work with windows 7 Basic interface,while computers with with more than 1GB of RAM that has the required hardware may be able to work with the windows 7 Aero interface,which provides an enhanced visual look,additional navigation options and animation.
Managing Programs:some operating system support a single user and only one program running at a time.others support thousands of users running multiple programs.A single user/single tasking operating system allows only one user to run one program at a time.for instance,if you are working on windows media players and you want to check your e-mail,you have to quit the windows media player program before you can run your e-mail program.smart phone and other mobile device are typical examples of single user/single tasking.A single user/multitasking operating system allows a single user to run more than one program.for instance e-mail program and windows media player can run simultaneously.when a computer is running two programs at the same time,one program is in the foreground and the others in the background.The one in the foreground is active program(in use).the other programs running but not in use are in the background.The foreground program usually displays on the desktop,while the background programs are hidden partially or completely behind the foreground program.
Managing Memory:The purpose of memory management is to optimize the use of random access memory(RAM).The operating system allocates,or assigns data and instructions to an area of memory while they are being processed.then,it carefully monitors the contents of memory.lastly,the OS releases these items from being monitored in memory when the processor no longer requires them.If you have multiple programs running simultaneously ,it is possible to run out of RAM.If the RAM is exhausted,the operating system may have to use virtual memory.operating system allocates a portion of a storage medium,usually the hard disk,to function as additional RAM with Virtual memory.As you interact with a program,part of it may be in physical RAM,while the rest of it is on the hard disk as virtual memory.Virtual memory is slower than RAM ,this is why a user may notice the computer slowing down while it uses virtual memory.
Coordinating Tasks:The operating system determines the order in which tasks are processed.A task,or job,is an operation the processor manages.This includes receiving data from an input device,and transferring items from storage to memory and from memory to storage.Multiuser operating system does not always process tasks on first come ,first served basis.sometimes,one user may have a higher priority than other users.In this case,the operating system adjusts the schedule of tasks.a device already may be busy processing one task when it receives a second task.This occurs because the processor at a much faster rate of speed compared to the peripheral devices.for example,if the processor sends five documents to a printer,the printer can print only one at a time and store as many documents as its memory can handle.While waiting for the device to be idle,the operating system places items in buffers.A buffer is a segment of memory in which items are placed while waiting to be transfered from an input device or to an output device.
Providing file management and other Utilities:Operating systems often provide users with the capability of managing files,searching for files,viewing images,securing a computer from unauthorised access,uninstalling programs,cleaning up disks,defragmenting disks,diagnosing problems,backing up files and disks,and setting up screen savers.
Updating Software Automatically:Many popular programs,including most operating systems,include an automatic update future that automatically provides updates to the program.with an operating system,these updates can include fixes to program bugs,or errors,enhancement to security,modifications to device drivers,access to new or expanded components such as desktop themes or games.Many software makers provide free downloadable updates,sometimes called a service pack,to users who have registered or activated their software.With operating systems,the automatic update future automatically alerts users when an update is available,further it can be configured to download and install the update automatically.
Controlling Networks:Some operating systems are designed to work with a server on a network.A server operating system is an operating system that organizes and coordinates how multiple users access and shares resources on a network.some operating systems have network futures built into them.In other cases,the server operating system is a set of programs separate from the client computers that access the network.When not connected to the network,the server operating system may assume some of the operating system functions. Compare colour laser printers provides color print output which are compatible with a wide range of operating systems.