There are three main categories of storage devices: optical, magnetic and semiconductor.
Explanation:
Optical storage, an electronic storage medium that uses low-power laser beams to record and retrieve digital (binary) data. In optical storage technology, a laser beam encodes digital data onto an optical, or laser, disk in the form of tiny pits arranged in a spiral track on the disk's surface.
Magnetic storage or magnetic recording is the storage of data on a magnetized medium. ... The information is accessed using one or more read/write heads. Magnetic storage media, primarily hard disks, are widely used to store computer data as well as audio and video signals.
Semiconductor memory is a digital electronic semiconductor device used for digital data storage, such as computer memory. ... Non-volatile memory (such as EPROM, EEPROM , and flash memory) uses floating-gate memory cells, which consist of a single floating-gate MOS transistor per cell.
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