An operating systems are is the software that serves as the mediator between the user's hardware and the applications he uses. It is responsible for controlling the hardware resources like the memory, the processors and the storage space available. It serves as the coordinator of all the activities done by the computer. If an airport can't function without an airport traffic controller, a computer will not be able to deliver unless an operating system is installed and functioning. An operating system can either come with a new computer unit purchased or it can be bought separately. After bootup, you usually see the operating system which will enable you to use the services available and helps you manage the programs installed as well as your disk space.
Operating systems provides two sets of services, the internal and the external. External services includes mechanisms on starting programs, managing files and other stored data and as well as maintaining the security of the computer system itself and are controlled by the user of the computer. Using several ways of communication with the user, it provides ways to select the applications the users would like to use. Internal services on the other hand are the "behind the scenes" services that are employed by the operating system to ensure that everything is running smoothly. If the external services are controlled by the user, these internal services are generally under the control of the operating system. These internal controls includes the control of input and output, allocating system resources, managing the storage space for installed programs and data saved on the computer and to detect any malfunction or miscommunications between the operating system and peripheral devices connected to the computer.
The following are the key functions of an Operating System:
Controlling Basic Input and Output
An operating system controls the flow of data into and out of the computer, as well as the flow of data to and from peripheral devices. It routes input to areas of the computer where it can be processed and routes output to the screen, a printer, or any other output device the user requests.
Detecting Equipment Failure
The operating system monitors the status of critical computer components to detect failures that affect processing. When the user turns on the computer, the operating system checks each of the electronic components and takes a quick inventory of the storage devices. For example, if an electrical component inside your computer fails, the operating system displays a message identifying the problem and does not let the user continue with the computing session until the problem is fixed.
Allocating System Resources
A system resource is any part of a computer system, such as a disk drive, memory, printer, or processor time, that can be used by a computer program. The operating system allocates system resources so programs run properly.
For example, each program instruction takes up space inside the computer and each instruction requires a certain amount of time to complete. The operating system ensures that adequate space is available for each program that is running and makes sure the processor quickly performs each program instruction.
The operating system also manages the additional resources required for using multiple programs or for providing services to more than one user at the same time. For example, if you want to run two or more programs at the same time, a process called multitasking, the operating system ensures that each program has adequate space and that the computer devotes an appropriate amount of time to the tasks prescribed by each program.
Manage Storage Space
The operating system keeps track of the data stored on disks and optical devices. The disks are like filing cabinets and your data as papers stored in file folders, and the operating system as filing clerk. The filing clerk takes care of filing a folder when you finish using it. When you need something from your filing cabinet, you ask the filing clerk to get it. The filing clerk knows where to find your folder. On your computer system, the operating system stores your data at some location on a disk. Although you might not know exactly where your data is stored on a disk, when you need the data again, you only need to ask the operating system t retrieve it.
Maintain Security
The operating system also helps maintain security for the data on the computer system. For example, the operating system might not allow the user to access the computer system unless he/she has a user ID and password.
References:
Bhor, Harsh (2012). Operating Systems. Retrieved from http://www.mu.ac.in/myweb_test/MCA%20study%20material/OS%20-%20PDF.pdf
Franklin, Curt (2013). How Operating Systems Work. Retrieved from http://www.howstuffworks.com/operating-system.htm
LearnFree.org (2013). What is an Operating System? Retrieved from http://www.gcflearnfree.org/computerbasics/2
Silberchatz, Abraham (2011). Operating System Concepts. Wiley. India.
Stallings, William. Operating Systems 5th Edition. Pearson Education. New York.
