ICT SHSM Certification Test – Part 1

Hardware vs. Software

Hardware refers to the physical parts of the computer – things you can see and touch.

Eg. monitor, keyboard, CPU, RAM

Software refers to the sets of instructions written by programmers so that the computer can perform certain tasks.

Eg. word processor, web browser, spreadsheet program

Bits and Bytes Information is stored within a computer

as a series of 0s and 1s This system of using 0s and 1s is called

the BINARY number system Each 0 or 1 is called a BIT (short for

“binary digit”) Each 0 represents an off “switch” or a

low voltage flowing through a circuit Each 1 represents an on “switch” or a

high voltage flowing through a circuit

Bits and Bytes Bits are arranged in groups of eight Each group of eight bits is called a BYTE Eg. 10110110 is an example of a byte Within a computer, bits and bytes are used

to represent all types of data: letters, numbers, colours, sound, etc.

When hardware components communicate with each other, they send 0s and 1s using voltages across a wire, light pulses, or wireless technology

Simple Model of a Computer Computer hardware can be organized into 7

general categories:Processing – the “brain” of the computer

Input – devices which take data from the user to the CPU

Output – devices which take data from the CPU back to the user

Primary Storage – short-term memory

Secondary Storage – long-term memory

Architecture – connects all the other parts together

Networking – allows computers to talk to each other, either locally or over the Internet

Input Processing Output

Primary

Storage

Secondary

StorageNetworking

Architecture

Simple Model of a Computer

Processing

Each computer contains one or more CPUs, which act as the “brain” of the computer

CPU = Central Processing Unit The CPU is essentially a large computer

chip which plugs into the motherboard The CPU contains millions of electronic

components called transistors, which act like switches

Processing

ControlUnit

Arithmetic-LogicUnit

Storage

There are 3 areas within a CPU:

Processing

ALU – Arithmetic Logic UnitThis part of the CPU does the mathematical

calculations and logical comparisons Control Unit

Directs traffic within the CPU and decides which instructions are to be executed at which time

StorageStores input data, intermediate processing

results, and data waiting to be outputted

Processing

CPUs are compared according to their clock rates, measured in Hertz (Hz).

Current computers contain 2, 4 or more processors within a CPU (dual-core, quad-core, …)

Because processors generate heat, cooling systems including fans and heat sinks are required to prevent over-heating.

Processing

The pins on the underside of a CPU “chip”, which plug into a computer’s motherboard.

A CPU chip plugged into a motherboard. A fan and/or heat sink will be attached to the top to prevent over-heating.

Input Devices

An input device is a piece of computer hardware that takes data from the user to the processor.

Examples of input devices include: mouse, keyboard, microphone, scanner, touch screen, joystick, game controller.

Input Devices

Mouse

Keyboard

Graphics Tablet

Joystick

Microphone

Scanner

Output Devices

An output device is a piece of computer hardware that takes data from the processor back to the user.

Examples of output devices include: monitor, printer, speakers.

Output Devices

Speakers

Monitor

Printer