1. Write a simple program to print the PID (process ID) and PPID (parent process ID) of the underlying process. Repeat the execution multiple times (from the shell), then answer the following questions: (a) Is the PID the same in all runs? Why/why not? (b) Is the PPID the same in all runs? Why/why not? Hint: use the getpid and getppid systems calls to get the PID and PPID of a process respectively. 2. Modify the program in part 1 so that the main process creates a child process, and each of the two processes prints its PID and PPID. The parent process must wait until the child process terminates. (a) Verify the parent-child relationship between the two processes. 3. Write a program that continuously asks the user to enter a command (with no arguments). When the user enters a command, the program forks a child process to execute it (using execlp) while it waits until the child finishes execution. The program quits when the user enters "exit" as a command. 4. Write a program to draw the following process tree. Verify the correctness of your solution using the PIDs and PPIDs of the generated processes. P P3 P Main process P4 Ps P6