DBMSs also support another type of lock called a latch, which is held for a much shorter
duration than a normal lock. A latch can be used before a page is read from, or written to,
disk to ensure that the operation is atomic. For example, a latch would be obtained to write
a page from the database buffers to disk, the page would then be written to disk, and the
latch immediately unset. As the latch is simply to prevent conflict for this type of access,
latches do not need to conform to the normal concurrency control protocol such as two-
phase locking.