A cache is a type of computer storage that holds data temporarily, usually a copy of the data from the permanent memory storage. Data accessed from the cache by an application is usually faster. Once data has been read once by the computer, a copy is stored on the cache.
The cache stores these data on a storage memory such as the RAM, and an algorithm is used to keep track of data reads and then determines which data will be deposited into the cache. The primary cache memory is built into the device microprocessor chip while the other two secondary levels are responsible for feeding the primary level.