Computer Hardware and Software
Computer Hardware and Software
1. Computer hardware
1.1 Inter-relationship between basic hardware
Input
Unit
Central
Processing Unit
Output
Unit
Storage Unit
For the typical computer system shown below. Fill in each of the blanks by one of the following:

input device

output device

storage unit
Speaker ( ________________)
Optical disc drive
Monitor
( ______________ )
( ____________ )
Floppy disk drive
( _________________ )
Keyboard
Mouse
( _________________ )
( _______________ )
A typical computer system
Do you where is the central processing unit (CPU) inside a computer system?
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Computer Hardware and Software
1.2 Functions of basic hardware components
Central Processing Unit (CPU) – controls all operations of the computer system.
Input unit – accepts input data and pass them to the CPU.
Output unit – produces information to users in the form of hard copies or screen display.
Storage unit – stores programs and data.
1.3 Examples of input devices and output devices
Categorize the following devices into input devices and output devices.
keyboard, monitor, printer, mouse, memory card reader, speaker,
graphics scanner, video projector, bar code scanner, handwriting
tablet
Input devices
Output devices
Can you suggest more input devices and output devices?
Input devices _____________________________________________________________
__________________________________________________________________________
Output devices ____________________________________________________________
__________________________________________________________________________
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Computer Hardware and Software
1.4 Storage unit
Storage devices can be divided into main memory and secondary storage.
Main memory
There are two types of main memory:

RAM – Random Access Memory

ROM – Read Only Memory
A RAM chip
Differences between RAM and ROM
RAM
Read and write – data can be read from or
ROM
Read only – data can only be read from
written to RAM.
ROM.
Temporary storage – when the computer
Permanent storage – data will not be lost
is switched off, all data stored in RAM will
when the computer is switched off.
be lost.
Secondary storage / Backing storage
Secondary storage can hold programs and data permanently for future use. It is needed because:

main memory can be used only temporarily

size of main memory is limited

main memory is expensive
1.5 Examples of secondary storage
Capacity
Unit Storage
Cost
Access Speed
Hard disk
Very high
Low
Very fast
DVD/CD
High
Low
Fast
USB thumb
drive
High
High
Very fast
Memory card
High
High
Very fast
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Computer Hardware and Software
2. Computer Software
2.1 System software
System software refers to software that controls the operation of computer equipment. For
example, starting up a computer, storing and retrieving files, executing of application software.
Operating system – a collection of system programs that
provides
an interface between the hardware and the user
controls
the overall operation of the computer system
Examples: Windows, Linux, DOS
Users
Operating system
Hardware
Application software
Chinese operating system is an operating system supporting Chinese characters. User can input
and edit Chinese characters. The system can accept Chinese characters, store the characters and
output the characters to the screen and to the printer. It also lets user create their own Chinese
characters.
Examples: Chinese Windows
Program to control
date and time
Program to
control fonts
Program to control
monitor display
Program to control
input methods
A part of a Chinese operating system
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Computer Hardware and Software
Chinese characters input method
Since Chinese characters are entered to the computer by normal keyboard. Chinese input methods
must be developed to help user entering Chinese characters. For examples, Changjei input method
(倉頡輸入法), Simplified Changjei (速成輸入法), phonetics (注音輸入法), Q9(九方輸入法).
Handwriting input method is the easiest method but the speed cannot be very fast.
A handwriting pad
2.2 Programming language
Programming languages are artificial languages designed to generate or express programs. Users
can use programming language to write programs in order to tell the computer what to do and
how to do.
Examples: Logo, BASIC, Pascal
FD 50
REPEAT 4 [FD 40
RT 90]
A Logo program to control the movement
of a turtle on the screen
SUM=0
FOR X=1 TO 100
SUM=SUM+X
NEXT X
PRINT X
sum:=0;
for x:=1 to 100 do
sum:=sum+x;
writeln(sum);
A BASIC program to calculate
1+2+3+...+99+100
A Pascal program to calculate
1+2+3+...+99+100
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Computer Hardware and Software
2.3 Application software
An application software is a program or a set of programs designed for a specific task.
Common types of application software:
Function
Create, edit, format, store
and print of text documents
Examples
MS Word, OpenOffice
Writer, Google Docs,
Spreadsheet
Perform automatic
calculations, format tabular
reports, prepare statistical
charts
MS Excel, OpenOffice Calc,
Google Docs
Database
Store, organize, modify and
searching of data records
Access, MySQL,
OpenOffice Base
Graphics
Create, modify and print
drawings, pictures or images
PowerPoint, Photoshop,
PhotoImpact
Web browser
Browse webpages in the
internet
Internet Explorer, FireFox,
Opera
Word processing
A database program
A word processor
A spreadsheet program
A web browser
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