CentralNotice From Wikipedia, the free encyclopedia Jump to: navigation , search For the Black Eyed Peas song, see The Time (Dirty Bit) . A dirty bit or modified bit is a bit that is associated with a block of computer memory and indicates whether or not the corresponding block of memory has been modified. [ 1 ] The dirty bit is set when the processor writes to (modifies) this memory. The bit indicates that its associated block of memory has been modified and has not yet been saved to storage . When a block of memory is to be replaced, its corresponding dirty bit is checked to see if the block needs to be written back to secondary memory before being replaced or if it can simply be removed. Dirty bits are used by the CPU cache and in the page replacement algorithms of an operating system . Dirty bits can also be used in Incremental computing by marking segments of data...