Operating System Services

An operating system provides an environment for the execution of programs. The specific services provided are differing from one operating system to another, but we can identify common classes. These operating system services are provided for the convenience of the programmer to make the programming task easy.

Program Creation: the operating system provides editors, debuggers, to assist the programmer in creating programs.
Programs Execution: A number of tasks required to execute a program, the tasks include instructions and data must be loaded into main memory, I/O devices and files must be initialized, and other resources must be prepared. The OS handles these tasks for the user.
Input/Output Operations: A running program may require input and output. This I/O may involve a file or an I/O device. A user program cannot execute I/O operations directly, the OS must provide some means to do so.
Error Detection: the operating system detects the different types of errors and should take appropriate action. The errors include memory error, power failure, printer out of paper, illegal instruction in the program(division by zero, arithmetic overflow, attempt to access illegal memory-local)
Resource Allocation: The operating systems collect all the resources in the network environment or a system and grant these resources to request process. Many different types of resources include CPU cycles, main memory, IO devices, file storage and so on.
Accounting: the operating system can be keep track of which users use how much time and what kind of computer resources used. This record keeping is useful to improve computing services
Protection: the operating system provides security mechanism to protect the unauthorized usage of files in the network environment.

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