Cache – A high-speed memory device that is faster than the memory or storage device otherwise used. For example, main memory can be used to cache data from SSDs or HDDs and make it accessible to applications, local or remote, faster than if they accessed the storage drives directly, with no intervening cache. Similarly a chunk of SRAM, faster than DRAM, can be used by CPUs to cache data otherwise held in memory (DRAM) and slower to access.