Fundamental definitions

• Block: a $B \times N$-word cache provides fast storage for up to B blocks, each consisting of N words

• Tag: Each block held in the cache must be tagged with its main memory address

• Read Hit: If tag matches address, the data is supplied to the processor

• Read Miss: no match: a block must be fetched from memory

• Allocate: when a new block is fetched, it is stored in the cache

• Replacement: to make space for a new block to be allocated in the cache, it may be necessary to displace an existing block.