What does "cache" mean?

Cache (pronounced "cash") is a small fast area of chip memory holding recently-accessed data, designed to speed up subsequent access to the same or nearby data. It is based on the fact that retrieving data from virtually instantaneous electronic memory chips is must faster than retrieving data from a magnetic storage medium such as a disk. When data is read from your hard drive to main memory (RAM) a copy is also saved in the cache, along with some additional nearby data. The cache monitors subsequent requests for data to see if the required data is already in the cache. If it is (a "cache hit") then itís returned immediately and the slower hard drive read isnít needed. If the data is not cached (a "cache miss") then it is fetched from the disk but also saved in the cache in case itís needed again.

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