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Computer Science IGCSEPDF 34
142 pagesrevision 46930
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➤ Secondary Storage
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Magnetic storage is non-volatile media that uses magnetic
polarity to store 0s and 1s.
A magnetic hard disk contains several metal discs coated with
magnetic material.
These discs are called platters.
Iron particles on the platters are magnetised to represent
binary data (0 or 1).
Each platter is divided into concentric circles (tracks) and
wedge-shaped sectors.
The point where they intersect is called a track sector.
Storage devices are non-volatile secondary storage that
retain data on a computer.
They store, access, and retrieve data such as software,
documents, images, and videos.
There are three types of storage:
○ Magnetic
○ Solid-state (flash memory)
○ Optical
Secondary storage provides long-term storage for programs
and data not in use.
It is needed because ROM is read-only and RAM is
volatile.
Stores data and programs while the computer is off
(non-volatile).
Slower than primary storage but has much higher capacity.
Ideal for backups and data archives.
Magnetic Storage