Cambridge O Level Computer Science · Syllabus 2210 · Hardware
Magnetic Storage
What is Magnetic Storage?
Magnetic storage is secondary storage in which data is held as the magnetic polarity of tiny areas on a spinning platter or a tape, read and written by a head that moves across the surface as it turns.
This definition is part of the Hardware chapter in Cambridge O Level Computer Science.
Magnetic Storage in context
Magnetic storage uses platters — rigid spinning discs coated with a magnetic material — which are divided into tracks and sectors. Data is read and written using electromagnets in a read/write head that moves across the spinning platter. A region of the surface is magnetised in one of two directions, and those two directions represent the 1s and 0s. The example named by the syllabus is the hard disk drive (HDD).
Questions students ask about Magnetic Storage
What is the difference between magnetic, optical and solid-state storage?
Magnetic storage, such as a hard disk drive, uses electromagnets in a read/write head to magnetise regions of a spinning platter in one of two directions, representing 1s and 0s. Optical storage, such as a CD, DVD or Blu-ray, uses a laser to read pits and lands on a disc's surface, which reflect light differently. Solid-state storage, such as an SSD, SD card or USB flash drive, has no moving parts and stores data by trapping electrons on floating gate transistors using NAND or NOR flash technology.