Secondary Storage is non-volatile storage which isn't directly accessible by the CPU.
Secondary Storage is non-volatile storage which isn't directly accessible by the CPU.
There are three forms of secondary storage: magnetic, flash, and optical, all of which will be covered over the next three pages.
Hard Disk Drives (HDDs) are the main form of magnetic storage in computers.
They are made up of magnetised metal disks, called "platters", spinning at a rate of around 10,000 revolutions per minute.
Binary data is represented by the direction of magnetisation (North is 1 and South is 0).
Each platter is divided into "tracks", and each track into "sectors".
There is a read/write head, like the needle on an old record player.
What are the advantages and disadvantages of using HDDs?
Tap/click to reveal HDDs offer very large storage capacities (several terabytes), and are also very cheap (<5p per GB). However, because of their moving parts, HDDs can be damaged by large impacts like drops.