Forking Processes: Practical Examples and Execution Flow

This lecture provides a detailed exploration of the fork system call in operating systems, illustrated through three practical examples. The instructor begins by introducing the concept of process management, highlighting the four essential system calls: fork, exec, wait, and exit. The first example demonstrates a simple program that forks itself, producing output that identifies the parent and child processes. The instructor explains the significance of header files and the entry point of the program, emphasizing the non-deterministic nature of process execution. The second example builds on the first, incorporating error checking and the wait system call, which allows the parent process to wait for the child to complete. This example illustrates a deterministic execution order, contrasting with the first example's non-determinism. Finally, the third example introduces the exec system call, showing how a child process can replace its memory space with a new program. The lecture concludes with a discussion on the synchronization of processes and the expected output of the programs.