A memory device, such as a floppy disk, a hard disk, or a removable cartridge, that is covered with a magnetic coating on which digital information is stored in the form of microscopic, magnetized regions.
A memory device, such as a floppy disk or a hard disk, that is covered with a magnetic coating. Digital information is stored on magnetic disks in the form of microscopically small, magnetized needles, each of which encodes a single bit of information by being polarized in one direction (representing 1) or the other (representing 0).
The definition of a magnetic disk is a type of data storage that uses magnetic patterns on a circular surface.
An example of a magnetic disk is a computer’s hard drive.
The primary computer storage device. Increasingly magnetic disks are being replaced by SSDs (see SSD). Like magnetic tape, disks are magnetically recorded and can be re-recorded over and over. Disks contain rotating platters with a mechanical arm that moves a read/write head across their surface. For more details, see hard disk and hard disk interfaces.Tracks and SpotsA disk's surface is divided into concentric tracks (circles within circles), and the thinner the tracks, the more storage. The data bits are recorded as magnetic spots on the tracks, and the smaller the spot, the greater the storage. See areal density.SectorsTracks are further divided into sectors, which hold a block of data that is read or written at one time; for example, READ SECTOR 782, WRITE SECTOR 5448. In order to update the disk, one or more sectors are read into the computer, changed and written back to disk. The operating system figures out how to fit data into these fixed spaces.Modern disks have more sectors in the outer tracks than the inner ones because the outer radius of the platter is greater than the inner radius (see CAV). See magnetic tape and optical disc.
Magnetic Disk SummaryThe following magnetic disk technologies are summarized below. Except for the hard disk, all of the following drives are no longer manufactured. However, media such as floppy disks, Zip and Rev cartridges are often available.