High Quality Content by WIKIPEDIA articles! In computer storage, disk buffer often ambiguously called disk cache or cache buffer is the embedded memory in a hard drive acting as a buffer between the computer and the physical hard disk platter that is used for storage. Modern hard disks come with 8 to 64 MiB of such memory. Since the late 1980s, nearly all disks sold have embedded microcontrollers and either an ATA, Serial ATA, SCSI, or Fibre Channel interface. The drive circuitry usually has a small amount of memory, used to store the bits going to and coming from the disk platter. The disk buffer is physically distinct from and is used differently than the page cache typically kept by the operating system in the computer's main memory. The disk buffer is controlled by the microcontroller in the hard disk drive, and the page cache is controlled by the computer to which that disk is attached. The disk buffer is usually quite small, from 2 to 32 MiB, and the page cache is generallyall unused physical memory.