Hard drive is a device that stores information in virtually all desktop and laptop computers. The drive includes one or more rigid magnetic disks that hold the data. These disks are called hard disks or platters. Many people use the term hard disk to refer to the entire hard drive. The platters are usually fixed inside the drive and cannot be removed. They are stacked on top of one another. Data are stored on each side of a platter's surface, on circular bands called tracks. A hard drive has thousands of tracks. Each side of a platter has a device called a read/write head that moves in and out to specific tracks of the spinning platter to store or to call up data for the computer to use. Hard drives are also known as fixed-disk drives.