buffer cache和 cache memory

buffer cache -- Stores the most-recently accessed blocks on block devices. This avoids having to re-read the blocks from the physical device.

buffer flushing daemon -- Writes the contents of delayed-write buffer buffers from the buffer cache to disk.

cache memory -- High-speed, low-access time memory placed between a CPU and main memory in order to enhance performance. See also level-one (L1) cache and level-two (L2) cache.