Broxburn Academy
CfE Computing
Hardware
Notes booklet
This topic covers the following CfE outcomes:
Computing Science 3-08c
Having gained knowledge and understanding of the components of a
computer, I can make an informed choice when deciding on the system
required for a specific purpose.
Computing Science 4-08d
Through research, I can gain knowledge of computer systems or
emerging technologies to understand their differing features and
consider their suitability for the world of work.
Hardware
The computer and the devices connected to it.
For example: keyboard, monitor, printer.
Software
The programs that can be run on the computer.
For example: Windows 7, Google Chrome, Paint.Net.
Basic computer structure
Most computer systems have five key components, as shown below:
Memory
Input devices
Processor
Output devices
Backing Storage
A computer system can be any computerised device.
For example: a desktop computer, a digital watch, a DVD player.
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Processor – the “brain” of the computer, fetches program instructions from
memory and carries them out.
Memory – allows the computer to keep track of the programs and data it is
currently using.
Input devices – allow the user to put information into the computer.
Output devices – allow the user to see or hear what the computer is doing.
Backing storage devices – allow the computer to store data and programs to
use another time.
Input, output and backing storage devices
Some examples of devices are listed below:
Input devices
Output devices
Backing storage devices
Keyboard
Monitor
Hard disc drive (HDD)
Mouse
Speakers
Flash drive (aka USB drive)
Scanner
Printer
CD-ROM / CD-R / CD-RW
Joystick
Headphones
DVD-ROM / DVD-R / DVD-RW
Microphone
Blu-ray disk (BD) / BD-R / BD-RE
Graphics tablet
Magnetic tape
Touchpad
Memory
There are two types of memory in most computer systems.
RAM (Random Access Memory) is the main memory, used to store programs
which are currently running.
 Its contents change constantly, with every action that is carried out on the
computer.
 It loses its contents when the power is switched off.
ROM (Read Only Memory) is used to store programs which will not change, such as
the program which loads up the operating system.
 Its contents cannot be changed, they are set when the ROM chip is
manufactured.
 Its contents are never lost, even when the power is switched off.
Processors
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The speed of a processor is can be used as a very basic way to judge the
performance of a computer system.
A higher processor speed is better.
Modern processors have speeds measured in GHz (Gigahertz), older processor
speeds were measured in MHz (Megahertz).
Units of storage
Capacity of storage devices and memory is measured using the following units:
Bits (b)
Bytes (B)
Kilobytes (KB)
Megabytes (MB)
Gigabytes (GB)
Terabytes (TB)
Petabytes (PB)
A single binary digit, 1 or 0.
8 bits
1024 bytes
1024 KB
1024 MB
1024 GB
1024 TB
Types of computer system
Here are some different types of computer system:
Desktop
Laptop
Tablet
Smartphone
Small enough to fit on a desk, but not easily portable.
Portable computer, generally a bit less powerful than desktop
computers but a smaller physical footprint.
Physically small portable computer with a touchscreen and multitouch capabilities, and no keyboard or mouse. Connects to internet
using wi-fi.
Mobile phone which includes functions such as web access, video
camera, etc and often has a touchscreen. Generally the least
powerful type of device, with relatively low RAM and processor
speeds. Connects to internet using wi-fi or 3G.
Operating System
The Operating System (OS) is the software which is required to make a computer
system work.
For example: Windows 7, Android, iOS.