3683477
Mind Map by James Hawksley, updated more than 1 year ago
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Created by James Hawksley
over 4 years ago
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3
Description
Computer Hardware
1 Devices
1.1 Input
1.2 Output
1.3 Hybrid
1.4 Assistive Technology
2 Secondary Storage
2.1 Purpose
2.1.1 Non-volatile device that holds data until it is deleted or overwritten.
2.1.2 Secondary storage is about two orders of magnitude cheaper than primary storage.
2.2 Types
2.2.1 Magnetic
2.2.1.1 Examples
2.2.1.1.1 Magnetic
tape
2.2.1.1.2 Floppy
Disk
2.2.1.1.3 Hard Disk Drives
2.2.1.2 How it works
2.2.1.2.1 It is coated
with iron
oxide.
2.2.1.2.2 This oxide is a
ferromagnetic
material.
2.2.1.2.3 As it is a ferromagnetic material,
meaning that if you expose it to a
magnetic field it becomes permanently
magnetized.
2.2.2 Optical
2.2.2.1 How it works
2.2.2.1.1 The spiral bumps on a CD starts in the center. CD tracks are so small that they have to be measured in microns which are millionths