What is the purpose of a system call in an operating system?

The system call is the programming way for executing the requesting the services in the program from kernel in the particular operating system.

The main purpose of the system call in the operating system is that it basically provide the different types of the services to the users by using the API (Application program interface) system.

It basically provide the interface for allowing the users to request the services between the operating system and a processor. In the linux there are basically three types of system call are as follows:

Fork Waitpid Exist