Tuesday, September 30, 2008

Operating System Services

Hello friends now its time to move forward with operating systems.In this post i am going to told you about the services that an operating system provides to a user.

Generally operating systems provide two types of services one that is provided to the programs and the other that is provided to the users of these programs.These operating system services are provided for the convenience of the programmer i.e to make the programming easier.Now lets begin with the first type of service that is provided to the user:

1.User Interface:As all we know almost all operating systems has user interface.Now this interface can be of any form either it may be command line interface,which uses text commands and a method for entering them or it may be graphical user interface(GUI) .In GUI the interface is a window system with a pointing device to direct I/O,choose from menus,and make selections and a keyboard to enter text.

2.I/O operations: Whenever a program is running it requires some I/O resources to complete its execution.For specific devices, special resources may be required such as a cd or dvd driver to for recording of a cd or dvd.For efficiency and protection,users cannot control I/O devices directly.Hence operating system provide some means to do I/O.

3.File system manipulation: The file system manipulation is a different area of interest.As all we know that some programs need to read and write of files and directories.They also need to create and delete them by name,search for a given file and list file information.So for doing all these instructions some program is required that include permissions management to allow or deny access to files or directories based on ownership.

[caption id="attachment_57" align="aligncenter" width="397" caption="Services that an operating system provides to its users".

4.Communications: Sometimes their exists a situation in which one process needs to exchange information with another process.Such communication may occur between the processes that executing on the same computer or between processes that are executing on different computer systems but exists in same computer network.Now this communication may be implemented by shared memory or through message passing,in which packets of information are moved between processes by the operating system.

5.Error Detection: One of the most important service that is provided by an operting system to its user is error detection.Error may occur in CPU,in memory,in I/O devices(such as parity error on tape,a connection failure on the network) and in the user program(such as arithmetic error,an attempt to access an illegal memory location).For each type of error,the operating system should take appropriate action to ensure correct and consistent computing.

All these are the services that are provided by an operating system to its user.
Hope you enjoy this post.Waiting for your comments for more improvement.