Friday, October 3, 2008

Operating System Services Part-2

Hello friends in the last post i told you about the services that an operating system provides to its user.Now in this post i am going to told you about the services that an operating system provides to itself for the efficient working of it.

1.Resource Allocation:Suppose when there are multiple users or multiple jobs exists at the same time,resources must be allocated to each of them.The main task of operating system is to manage all these resources.Some resources such as CPU cycles,main memory and file storage may have special allocation code,whereas others such as I/O devices may have much more general request and release code.To use all these resources in the best efficient way operating system have CPU scheduling routines that take into account the speed of the CPU for the CPU resources.There may also be routines to allocate printers,modems,USB storage drives,and other peripheral devices.

2.Accounting:If we desire to keep track of which users use how much and what computer resources then operating system also provides this facility in the form of accounting.This record keeping may be used for for billing purpose of the users or simply for accumulating usage statistics.Usage statistics may be a valuable tool for researchers who wish to reconfigure the system to improve computing services.

3.Protection and Security:
When several separate processes execute concurrently,it should not be possible for one process to interfere with the others or with the operating system itself.Protection involves ensuring that all access to system resources are controlled.Security of the system from the outsiders is also an important issue.Such security starts with requiring each user to authenticate himself or herself to the system,usually by means of a password,to gain access to system resources.This security is also applicable to the external I/O devices,including modems and network adapters from invalid access attempts .If a system is to be protected and secure,precautions must be instituted throughout it.

Hope you enjoy this post.Waiting for your response for more improvement.