<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (August 2012) (Learn how and when to remove this template message) </Td> </Tr> <P> In computer storage, disk buffer (often ambiguously called disk cache or cache buffer) is the embedded memory in a hard disk drive (HDD) acting as a buffer between the rest of the computer and the physical hard disk platter that is used for storage . Modern hard disk drives come with 8 to 256 MiB of such memory, and solid - state drives come with up to 1 GB of cache memory . </P> <P> 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 data going to and coming from the disk platters . </P> <P> The disk buffer is physically distinct from and is used differently from 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, ranging between 8 and 256 MiB, and the page cache is generally all unused main memory . While data in the page cache is reused multiple times, the data in the disk buffer is rarely reused . In this sense, the terms disk cache and cache buffer are misnomers; the embedded controller's memory is more appropriately called disk buffer . </P>

What is the cache on a hard drive mean