Course no: CSE 1100

Course Title: Computer Fundamentals and Ethics

Lecture 3

EMRANA KABIR HASHI

ASSISTANT PROFESSOR
DEPARTMENT OF CSE, RUET
 2
Hardware

 Hardware = The physical

components that make up a
computer system.
 More in a moment…
 3
Hardware

 Physical parts of the computer are called hardware.

 You can touch, see and feel hardware.
 Hardware is constructed using physical materials or components.
 Computer is hardware, which operates under the control of a software.
 If hardware is damaged, it is replaced with new one.
 Hardware is not affected by computer viruses.
 Hardware cannot be transferred from one place to another electronically
through network.
 User cannot make new duplicate copies of the hardware.
 4
Software

 Software = The programs

(instructions) that tell the
computer what to do.
 System Software
 Application Software
 Stored on a storage media such as
hard disk, CD-ROM, floppy disk, tape,
etc.
 More later…
 5
Software

 A set of instructions given to the computer is called software.

 You cannot touch and feel software.
 Software is developed by writing instructions in programming language.
 The operations of computer are controlled through software.
 If software is damaged or corrupted, its backup copy can be reinstalled.
 Software is affected by computer viruses.
 Software can be transferred from one place to another electronically through
network.
 User can make many new duplicate copies of the software.
 6
Hardware Vs Software comparison chart

Hardware Software
Collection of instructions that enables a user
to interact with the computer. Software is a
Devices that are required to store and
Definition program that enables a computer to perform
execute (or run) the software.
a specific task, as opposed to the physical
components of the system (hardware).
Input, storage, processing, control, System software, Programming software,
Types
and output devices. and Application software.
CD-ROM, monitor, printer, video card, Quickbooks, Adobe Acrobat, Winoms-Cs,
Examples scanners , label makers, routers , and Internet Explorer , Microsoft Word , Microsoft
modems. Excel
Inter Hardware starts functioning once To deliver its set of instructions, Software is
dependency software is loaded. installed on hardware.
 7
Hardware Vs Software comparison chart

Hardware Software

Hardware serve as the delivery system for To perform the specific task you need to
software solutions. The hardware of a complete. Software is generally not needed
Function computer is infrequently changed, in to for the hardware to perform its basic level
comparison with software and data, which are tasks such as turning on and responding to
“soft” in the sense that they are readily input.
created, modified, or erased on the compute

Hardware failure is random. Hardware does Software failure is systematic. Software does
Failure
have increasing failure at the last stage. not have an increasing failure rate.

Software does not wear out over time.

Durability Hardware wears out over time. However, bugs are discovered in software as
time passes.
Nature Hardware is physical in nature. Software is logical in nature.
 8
Hardware Components

Know these!
 9
The Processor

Let’s open the box!

 10
The Processor

circuit board = a board with integrated circuits

(microchips)
 system board or motherboard
 interface boards or expansion boards
system board or motherboard = a single circuit
board with the components which make up the
computer’s processor for a microcomputer, including
the:
 CPU (Central Processing Unit)
 Memory
 RAM
 ROM or ROM BIOS
 expansion slots
11
12
 13
The Processor: The CPU

CPU (Central Processing Unit) =

A complex collection of electronic
circuits on one or more integrated
circuits (chips) which:
1. executes the instructions in a
software program
2. communicates with other parts
of the computer system,
especially RAM and input devices
 14
Input and Output Devices

INPUT SYSTEM UNIT OUTPUT

PERMANENT
STORAGE
 15
Input Devices

 Enter information into a

computer
 Examples:
 Mouse
 Keyboard
 Trackball
 Touchpad
 Light pen
 Joystick
 Digital camera
 Microphone
 Bar code reader
 Scanner
 16
Input Devices

Keyboard: The keyboard is very much like a standard typewriter keyboard with a
few additional keys. The basic QWERTY layout of characters is maintained to
make it easy to use the system.
 17
Input Devices

Indirect Pointing Devices

Mouse: A device that controls the movement of the cursor
or pointer on a display screen. A mouse is a small object
you can roll along a hard and flat surface

Trackball: A trackball is an input device used to enter motion

data into computers or other electronic devices. It serves the
same purpose as a mouse, but is designed with a moveable
ball on the top, which can be rolled in any direction.
Touchpad: A touch pad is a device for pointing (controlling
input positioning) on a computer display screen. It is an
alternative to the mouse.
 18
Input Devices

Direct Pointing Devices

Touch Screen: It allows the user to operate/make selections by simply
touching the display screen.
 Often used for applications with occasional use, for example
 Bank ATMs, Information Managements, etc.
 No extra hardware - used for input and for output
 Can be precise to 1 pixel
 Good for menu choice - not so good for other functions
 Tiring if at wrong angle (needs to be 30-45% from horizontal)
 Get greasy, jammy
 Finger can obscure screen
 Alternative - use stylus to touch screen, or lightpen
 19
Microphones - Speech Recognition

• Use a microphone to talk to your computer

• Add a sound card to your computer
• Sound card digitizes audio input into 0/1s
• A speech recognition program can
 process the input and convert it into
 machine-recognized commands or
 input
 20
Audio Input: Speech Recognition

 Speech recognition is a type of

input in which the computer
recognizes words spoken into a
microphone.
 Special software and a microphone
are required.
 Latest technology uses continuous
speech recognition where the user
does not have to pause between
words.
 21
Microphones - Speech Recognition
 22
Digital camera

 A digital camera can store many more pictures than an ordinary

camera. Pictures taken using a digital camera are stored inside its
memory and can be transferred to a computer by connecting the
camera to it. A digital camera takes pictures by converting the light
passing through the lens at the front into a digital image.
 23
Scanner

 A scanner can be used to input pictures and text into a

computer. There are two main types of scanner; Hand-held and
Flat-bed.
 24
Light pen

• A light pen is a small ‘pen-shaped’ wand, which contains light

sensors.
• It is used to choose objects or commands on the screen either
by pressing it against the surface of the screen or by pressing a
small switch on its side.
• A signal is sent to the computer, which then works out the light
pen’s exact location on the screen.
• The advantage of a light pen is that it doesn’t need a special
screen or screen coating.
 25
Bar codes

• A bar code is a set of lines of different thicknesses that

represent a number

• Bar Code Readers are used to input data from bar codes. Most
products in shops have bar codes on them

• Bar code readers work by shining a beam of light on the lines

that make up the bar code and detecting the amount of light
that is reflected back
 27
Output Devices: Engaging our
Senses

 Output devices are peripheral devices that enable us to view or

hear the computer’s processed data.
 Visual output – Text, graphics, and video
 Audio output – Sounds, music, and synthesized speech
 28
Output Devices

 Send information out from a PC

 Examples:
 Speakers
 Monitors
 Visual Display Unit (VDU), Cathode
Ray Tube (CRT), Liquid Crystal
Display (LCD), Light-Emitting Diode
(LED)
 Printers
 29
Monitors

 A monitor is a peripheral device which

displays computer output on a screen.
 Screen output is referred to as soft copy.
 Types of monitors:
 Cathode-ray tube (CRT)
 Liquid Crystal Display (LCD or flat-panel)
 30
Monitors

CRT
 cathode ray tube
 electrongun shoots a stream of electrons at a specially phosphor-
coated screen
 on impact, the phosphor flares up for a fraction of a second
 electron gun sweeps across the screen many times a second
LCD
 liquid crystal display
 one of several types of “flat-panel” displays
 forms output by solidifying crystals and “backlighting” the image
with a light source
 TV sets are CRTs and many desktop monitors use this technology
 LCD is primarily used for laptops and other portable devices
 31
Video Display Terminology

 Pixel
 picture element (smallest unit of an image,
basically a single dot on the screen)
 Resolution
 number of pixels in the image
 Common resolution size is 1024x768
 Refresh rate
 how often a CRT’s electron gun rescans
The CRT electron gun
“shoots” 3 electrons at
 LCD displays do not use an electron gun, so do not
the screen representing
perform refreshing
the amount of red, green
and blue for the pixel
 32
Printers

 Ink Jet Printer

 least expensive, color, slower with a higher per page cost than laser printers

 Laser Printer
 More expensive, faster, lower per page cost than ink jet,
 33
Printers

 A printer is a peripheral device

that produces a physical copy or
hard copy of the computer’s
output.
 Types of Printers
34
Inkjet Laser

  Laser printer works like a copier

Inkjet printer, also called a bubble-jet, makes
characters by inserting dots of ink onto paper  Quality determined by dots per inch (dpi)
 produced
Letter-quality printouts
 Color printers available
 Cost of printer is inexpensive but ink is costly
 Expensive initial costs but cheaper to
operate per page
 35
Plotter

 A plotter is a printer that uses a pen that moves over a large

revolving sheet of paper.
 It is used in engineering, drafting, map making, and
seismology.
 36
Audio Output: Sound Cards and Speakers

 Audio output is the ability of the computer to output sound.

 Two components are needed:
 Sound card – Plays contents of digitized recordings
 Speakers – Attach to sound card