What are the Process Management System Calls?

System calls provide an interface between user programs and the operating system. When a user program needs to request services from the kernel, it uses system calls as a programmatic way to access OS functionality.

Types of System Calls

The operating system provides different categories of system calls −

• Process Management − Creating, terminating, and controlling processes

• File Management − Creating, reading, writing, and deleting files

• Directory Management − Creating and managing directory structures

• Device Management − Requesting and releasing devices

• Information Maintenance − Getting and setting system information

Process Management System Calls

Process management system calls are used to create, control, and terminate processes. The primary system calls include fork(), exec(), wait(), and exit().

Key Process Management System Calls

fork() System Call

The fork() system call creates a duplicate process (child process) from the parent process. Both processes contain identical copies of the program code, data, and file descriptors. The fork() call returns different values −

• 0 − Returned to the child process

• Child's PID − Returned to the parent process

• -1 − Indicates fork failure

exec() System Call

The exec() family of system calls replaces the current process memory image with a new program. The child process often uses exec() after fork() to run a different program than the parent.

wait() System Call

The wait() system call suspends the parent process execution until one of its child processes terminates. It also allows the parent to obtain the exit status of the terminated child process.

exit() System Call

The exit() system call terminates the calling process and returns an exit status to the parent process. All open file descriptors are closed and resources are released.

Example − Process Management Flow

Conclusion

Process management system calls provide the fundamental mechanisms for creating, controlling, and terminating processes in an operating system. The combination of fork(), exec(), wait(), and exit() enables complex process hierarchies and inter-process communication, forming the backbone of multitasking operating systems.