The document discusses different CPU scheduling algorithms used by an operating system's process scheduler to assign processes to the CPU. It describes First-Come, First-Served (FCFS) scheduling, Shortest-Job-First (SJF) scheduling, Round Robin (RR) scheduling, and Multiple-Level Queues scheduling. It also defines key timing metrics for processes like arrival time, completion time, burst time, turnaround time, and waiting time. FCFS scheduling follows the principle of processing processes in the order of their arrival in the ready queue on a first-come, first-served basis.