SERVICS OF OPERATING SYSTEM – an operating system an environment for the execution of program. The operating provides certain services to the program to the user of those programs to the user of those programs. there program some common services provided by operating system -
1. User interface
2. Program execution
3. Input/output operation
4. File system manipulation
5. Communication
6. Resource allocation
7. Accounting
8. Protection and security

       
        A view of operating system services



1. User interface Facility – User interface given by operating system which is the main service of OS.
There are three type of interface –
1. CLI
2. BATCH
3. GUI

1. CLI – (command line interface) in which use different command entering by keyboard.
2. BATCH – in which command and directories to control those command are entered into files.
3. GUI – it is the windows system interface with a pointing to direct I/O choose from menus and make selection.
2. Program execution – the system must be able to load program into memory and to run this program, the program must be able to end its execution either normally or abnormally (indicting error).
3. Input/output operation – during execution of program use input/output device is certainly required. These I/O may be form of file or form of input/output device. User normally cannot control I/O device directly so that must require device driver provided by operating system.
4. File system manipulation – in file system service user need to read or write. Sometime user creates and delete file by name so these service are also provided by operating system. Operating system also provides permission management to allow or delay access to file or directories based on file ownership.
5. Communication – message from one process to another or message from one computer to another computer communication may be implemented by sharing memory more than one process or message passing.
6. Error detection – operating system display time to time error detection message to the user error may be occur in the cpu and memory and hardware (corrupted memory or power failer).
7. Resource allocation – operating system decide that which resource should be allocated to which user job. Many times different job are handled simultaneously which require different amount of memory allocation this is done by operating system. Some time different job required different hardware like – monitor, printer etc.
8. Accounting – which user use how much and what kind of computer resource distract is recorded by operating system, also record number of login user, number of resources, free available resources etc is monitor by operating system.
9. Protecting system – multiple user are protected by operating system through login name with password, operating system give authorization of reading, writing and execution by some method like – encryption and decryption.