a cache that stores copies of frequently used disk sectors in random access memory (RAM) so they can be read without accessing the slower disk
Microsoft Computer Dictionary
n. A portion of a computer’s random access memory (RAM) set aside for temporarily holding information read from disk. A disk cache does not hold entire files, as does a RAM disk (a portion of memory that acts as if it were a disk drive). Instead, a disk cache is used to hold information that either has recently been requested from disk or has previously been written to disk. If the required information remains in a disk cache, access time is considerably faster than if the program must wait for the disk drive mechanism to fetch the information from disk. See also cache. Compare disk buffer.
