Operating System Services
An operating system provides services to programs and to the users of those programs. It provides an environment for the execution of programs. The services provided by one operating system is different than other operating system.
Operating system makes the programming task easier. The common services provided by the operating system is listed below.
- Program execution
- I/O operation
- File system manipulation
Program execution: Operating system loads a program into memory and executes the program. The program must be able to end its execution, either normally or abnormally.
I/O operation: I/O means any file or any specific I/O device. Program may require any I/O device while running. So operating system must provide the required I/O.
File system manipulation: Program needs to read a file or write a file. The operating system gives the permission to the program for operation on file.
Communication: Data transfer between two processes is required for some lime. The both processes are on the one computer or on different computer but connected through computer network Communication may be implemented by two methods: shared memory and message passing.
Error detection: Error may occur in CPU, in I/O device or in the memory hardware. The operating system constantly needs to be aware of possible errors. It should take the appropriate action to ensure correct and consistent computing.
Operating system with multiple users provide following services.
- Resource allocation
An operating system is a lower level of software that user programs run on. OS is built directly on the hardware interface and provides an interface between the hardware and the user program. It shares characteristics with both software and hardware.
We can view an operating system as a resource allocator. OS keeps track of the status of each resource and decides who gets a resource, for how long, and when OS makes sure that different programs and users running at the same time but do not interfere with each other. It is also responsible for security, ensuring that unauthorized users do not access the system.
The primary objective of operating systems is to increase productivity of a processing resource, such as computer hardware or users.
The operating system is the rust program run on a computer when the computer boots up. The services of the OS are invoked with a system call instruction that is used just like any other hardware instruction.
Name of the operating systems are: DOS, Windows 95, Windows NT/2000, UNIX, Linux etc.