Learn in the textbookMemory Hierarchy and DRAM Standards & Modules
DefinitionCache memory (キャッシュメモリ) sits between the CPU and main memory and is a fast, small memory that holds copies of frequently used data and instructions.
ExplanationThe CPU runs far faster than main memory, so reading main memory every time would leave the CPU waiting. Cache memory therefore holds the data most likely to be needed, raising the share of reads that find their target there (a hit) and cutting the wait. Because it is small, a full cache has to evict something, such as the data that has gone unused the longest (the LRU method).
AnalogyLike a kitchen where any seasoning you just used stays next to the stove, and when that space fills up, the one left unused the longest goes back to the shelf at the back.
Memory hookThe English word cache means a hidden store or stash: a place to quietly keep supplies within reach.