The document defines the key components of a computer system including hardware, software, and input/output/storage devices. It describes hardware as the physical parts like peripherals for input/output and storage. Software are sets of instructions that control the computer's operation. Input devices allow data to enter the system, storage devices save data long-term, and output devices present data to the user. The purpose of each is also outlined.

1. 1
Components of a Computer System
Learning Objectives:
• By the end of this lesson all of you will;
– define the terms hardware, software, input device, storage device and output device;
– describe the purpose of input devices, storage devices and output devices;
Hardware
Hardware are the physical components of a computer – eg the input devices, output devices, primary storage
(memory) and secondary storage (backing store), Central Processing Unit etc. Note that input and output devices are
collectively known as peripherals.
External Hardware
 Printer
 Keyboard
 Mouse
 Microphone
Internal Hardware
 Hard drive
 CPU
 Fan
 Motherboard
 Soundcard
Software
Software are the setsof instructions/programsthatare loadedintothe memoryof the computerinorder to perform
a task or to control the operationof the computer.
SystemsSoftware ApplicationSoftware
Operatingsystems Word processors
Utilities Webbrowsers
User interface Game applications
Input Device
An inputdevice ishardware thatallowsdatatobe enteredintoacomputer.
Manual Input Automatic Input
Keyboard Barcode reader
Mouse Sensor
Microphone Magneticstripe reader
Scanner Optical markreader(OMR)
Storage
A storage device ishardware thatallowsdatato be saved,long-term, afterithasbeeninputtedintothe computer.Examples
include;
• Hard drive
• DVD
• CD
• Flashmemory(USB)
Output Devices
A storage device ishardware that presentsthe dataina suitable formats. Examplesinclude;
• Monitor
• Printer
• Projector
• Speakers
ComputerSystems
A computer systemisone that is able totake a setof inputs,processthem,
and create a set of outputs.Thisisdone usinga combinationof hardware and
software.
Task 1:
Group yourself intofivegroups. Summarizethe lessonvocabularyand describethe central processingunitandhow
computerswork. Presentin5 minutesinourclass.

2. 2
Input Devices
The purpose of an input device is to provide data in a computer system ready for processing.
Storage Devices
The purpose of a storage device tostore data and software forlateruse.The storage device willmake some use of physical
effect to represent the data.
• CD, DVD, Blu-Ray – a laser burns dark pits onto the medium. Each pit is a binary digit.
• Hard drives and magnetic tape use magnetic domains to represent data.
• Flash drive use electric charge to store the data
A primary storage device is the main computer storage device, and a secondary device is one where you can also store
files, but is not the main storage you use.
Task 2: Use your notesand reference booksandothermaterialsinthe library or do a ‘shop search’ to find out about features
of different storage devices and fill in information on the ‘Comparison sheet’.
Item Size Storage Capacity
Mobility (fixed or
movable)
Usage
(Describe
and give
examples)
Is it rewriteable?
(Can it be used again
and again?)
Hard Disk
USB Flash Disk
(Please add as
many as you can)
Task 3:
 Using your smart phone, or a school camera you will need to find 5 different examples of input and output devices
around the school.
 Use your imagination and think of examples other than ones found in a computer room.
 For each image you will need to explain where it is found in the school, and what its purpose is.
Output Devices
Output is the stage where the information obtained by the processing is presented to the user in a suitable format.
Examples include;
• A printout of exam grades
• A digital display on a petrol pump
• A sound from a smoke alarm
Review Learning