Ex. 2.15- In a multi-threaded system with a round-robin scheduling at the process-level, implement a thread-level round-robin scheduler in pseudocode. Ex. 2.17-Write a pseudo-code for exec0, fork0. waidpid0, and exit0 system calls. Explain how these system calls are inter-related Ex. 2.19 -In Unix, there is a category of processes called zombie process. What are these? Ex. 2.15- In a multi-threaded system with a round-robin scheduling at the process-level, implement a thread-level round-robin scheduler in pseudocode. Ex. 2.17-Write a pseudo-code for exec0, fork0. waidpid0, and exit0 system calls. Explain how these system calls are inter-related Ex. 2.19 -In Unix, there is a category of processes called zombie process. What are these