When using virtual memory, what happens when a page fault occurs and the operating system cannot find a free frame in physical memory?

When a page fault occurs, the operating system attempts to load the required page into memory. If no free frames are available, the OS must replace an existing page using a page replacement algorithm such as FIFO, Optimal, or LRU. The chosen algorithm determines which page is swapped out of physical memory to make room for the new page. This approach is fundamental to virtual memory systems, allowing processes to execute even when their memory demands exceed the available physical memory. Why Other Options are Incorrect: A) The process is terminated: The OS does not terminate the process unless a severe error occurs, such as a protection fault. B) The page is loaded into a random memory frame: Pages are never loaded into random frames; the OS follows a replacement strategy. D) The OS reduces the process’s memory size: Reducing memory size is not a response to page faults; instead, page replacement is used. E) The process continues execution without any changes: The process cannot continue until the required page is loaded into memory.