cache

A cache is generally an intermediate region in which data are held, so as to be more accessible after transfer to/from a slower medium. For example, a disk cache contains copies for frequently-used data in memory, in the hope that when a future disk read occurs, the data will already be available. Processors generally contain code and/or data caches for the same reason: modern processors work at much higher speeds than their main memory, and memory accesses for each instruction executed are much slower than reading from a fast local cache.