What are the Services provided by Operating System?
An operating system provides an environment for the execution of programs. Operating System provides certain services to and the users of those programs. These OS services are provided for the convenience of the programs programmer to make the programming task easier.
1) Program Execution
The system must be able to load a program into memory and to run it. The program must be able to end its execution either normally or abnormally
2) I/O operation
A running program may require I/O.This I/O may involve a file or an I/O device. For specific devices, special functions may be desired. For efficiency and protection, users cannot control I/Odevices directly. Therefore OS can control I/O devices
3) File-System manipulation
The file system should be obvious that programs need to read and write files. They also need to create and delete files by name.
4) Communication
One process may exchange information to another process. There are two ways needs to exchange information with another process
· Communication takes place between processes executing on the same computer.
· Communication takes place between processes executing on different computer system that are tied together by a computer network.
5) Error detection
Error may occur in CPU and memory hardware, in I/O devices or in the user program. For each type of error, the OS should take the appropriate action to ensure correct and consistent computing.
In addition, another set of OS functions exists for helping the user and ensuring the efficient operation of the system itself.
Systems with multiple users can gain efficiency by sharing the computer resources among the users.
1) Resource Allocation
When there are multiple users or multiple jobs running at the same time, resources must be allocated to each of them. The resources are managed by the operating system.
2) Accounting
The record of which users use how much and what kinds of computer resources is kept for accounting or simply for accumulating usage statistics. Usage statistics is a tool used to reconfigure the system to improve computing resources
3) Protection
When several disjoint processes execute concurrently, it should not be possible for one process to interfere with the other or with the operating system itself. Protection involves ensuring that all access to system resources is controlled. Security of the system starts with each user having to authenticate by means of password
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