Minor page fault :If the page is loaded in memory at the time the fault is started, but is not checked in the memory management unit as being loaded in memory, then it is named a minor or soft page fault. The page fault handler in the operating system merely needs to create the entry for that page in the memory management unit point to the page in memory and show that the page is loaded in memory; it does not require reading the page into memory. This would happen if the memory is shared by different process and the page is already send into memory for other process. The page could also have been replaced from a process's Working Set, but not yet erased to disk or written, such as in operating system machines that use Secondary Page Caching. Since these faults do not call disk latency, they are faster and less cost effective than major page faults.