System Calls

System calls are the interface between the user level programs and the operating system. System calls are used by the user level programs to request the services of the kernel. The kernel then provides the requested service and returns the result to the user level program.

Types of System Calls

There are various types of system calls based on the services they provide. They are:

1. Process Control: These system calls are used to create, manage and terminate processes. Examples include fork(), exec(), wait(), etc.

2. File Management: These system calls are used to create, open, read, write, close, delete, and manipulate files. Examples include open(), read(), write(), close(), etc.

3. Device Management: These system calls are used to control and communicate with the devices attached to the system. Examples include read(), write(), ioctl(), etc.

4. Memory Management: These system calls are used to allocate and deallocate memory to the processes. Examples include malloc(), free(), etc.

5. Network Management: These system calls are used to establish, maintain and terminate network connections. Examples include socket(), bind(), connect(), etc.

Among the given options, BIOS is not a type of system call. BIOS (Basic Input/Output System) is a firmware interface that initializes and tests hardware components during the boot process and provides runtime services to the operating system and applications.

Therefore, the correct answer is option 'C'.