Priority preemptive scheduling is a CPU scheduling algorithm where processes with higher priority are given preference over processes with lower priority. The CPU can preempt a running process if a higher priority process becomes available, allowing for better response time and throughput for high-priority tasks.
Peterson's solution is a synchronization algorithm for mutual exclusion in concurrent programming. It ensures that multiple processes or threads can access a shared resource without interfering with each other. The algorithm uses two shared variables and strict turn-taking to guarantee mutual exclusion and prevent deadlock.
First-Come-First-Serve (FCFS) is a disk scheduling algorithm where the requests are processed in the order they arrive. The head of the disk moves in a direction, servicing all requests until it reaches the end and then moves back. It has high waiting time for requests that arrive later in the queue.
Optimal Page Replacement (OPR) is a page replacement algorithm where the page to be replaced is the one that will not be needed for the longest period of time in the future. It provides optimal performance, but requires future knowledge of the reference pattern which is not practical, hence rarely used.