In computing, a system call is how a program asks for a service from an operating system''s kernel. This may contain hardware related services (for example accessing the hard disk), creating and executing new methods, and communicating with integral kernel services (like scheduling). System calls give the interface among a process and the operating system.
The major types of system calls are as follow:
1. Process Control: These types of system calls are used to manage the processes. Some illustrations are end, abort, execute, create process, load, terminate process etc.
2. File Management: These types of system calls are used to organize files. Some illustrations are Create file, delete file, close, read, open, and write etc.
3. Device Management: These types of system calls are used to control devices. Some examples are release device, request device, read, write, get device attributes etc.
4. Information Maintenance: These types of system calls are used to put system data and get process information. Some illustrations are time, id, OS parameters, time used etc.
5. Communications: These types of system calls are used to set up a connection. Some examples are send message, receive messages, terminate etc