1. TYPES AND COMPONENTS
OF COMPUTER SYSTEM
1.3 OPERATING SYSTEM
Pages 10-14
REMINDER HOMEWORK#1 – DUE:
THEORY WORKBOOK
Q7 page 9
LEARNING OBJECTIVES:
 Differentiate analogue and digital data.
 Discuss the general tasks of a typical operating system.
• Identify the different types of user interfaces.
• Describe each type of user interfaces.
ANALOGUE VS. DIGITAL DATA
ANALOGUE VS. DIGITAL DATA
• Digital data consists of 0 and 1, the values or data that can be read only
by the computer. It can only have discrete, and discontinuous values.
• Analogue data consists of data in real world. It is the physical data that
changes smoothly from one value to the next.
• If analogue data is being sent to a computer, it must be first converted
into digital data by a hardware known analogue to digital converter
(ADC)
• If the computer is controlling a device then the digital output from the
computer needs to be converted into analogue form by a digital to
analogue converter (DAC)
OPERATING SYSTEM
 Enables computer systems to function and allow the users to
communicate with computer systems.
 General tasks of a typical OS includes:
 Control of the operation of the input, output and backing storage devices
 Supervising the loading, running and storage of application programs
 Dealing with errors that occur in application programs
 Maintaining security of the whole computer system
 Maintaining a computer log
 Allowing communication between user and the computer system through the
user interface
Types of user interfaces.
Operating systems offer various types of user
interface.
• command line interface (CLI)
• graphical user interface (GUI)
• dialogue-based user interface
• gesture-based user interface
7
Command Line Interface (CLI)
• requires a user to type in instructions to
choose options from menus, open a file, etc.
• user needs to learn a number of commands
just to carry out basic operations
8
Graphical User Interface (GUI)
•
•
•
allows the user to interact with a computer using
pictures or icons (symbols)
WIMP (Windows Icons Menu and Pointing) – use on
personal computers (PCs), where a mouse is used to
control a cursor and icons are selected to open/run
windows
touch screen devices use
post-WIMP where fingers
are in contact with the
screen allowing actions
such as pinching and rotating
9
CLI vs. GUI
Interface
Advantages
Disadvantages
CLI
• user is in direct communication
with computer
• user is not restricted to a
number of predetermined
options
• possible to alter computer
configuration settings
• user needs to learn a number of commands
to carry out basic operations
• all commands need to be typed in, which
takes time and can be error prone
• each command must be typed in using the
correct format, spelling and so on
• more difficult to edit once commands are
entered
GUI
• user doesn’t need to learn any
• uses up considerably more computer
commands
memory than CLI
• more user-friendly; icons are
• user is limited to the icons provided on the
used to represent applications
screen
• a pointing device is used to click • needs an operating system, to operate which
on an icon to launch the
uses up considerable memory
10
application which is simpler that
typing commands
Who do you
think will use
each interface
mentioned? CLI
and GUI
11
Dialogue-based User Interface
12
Dialogue-based User Interface
• use human voice to give commands to
computer system (voice activation control)
• could be find in phones, cars, home control
system
• Amazon Alexa, Google Now, Apple Siri,
Microsoft Cortana – personal assistants
using voice commands
13
Dialogue-based User Interface
14
Gesture-based User Interface
•
•
•
•
rely on human interaction by the moving of hands, head
or even the feet
allows human to interface with computer in a more
natural fashion without the need for any mechanical
devices
uses techniques known as computer vision and image
processing
either a sensor or a camera is used to pick up the
gesture and a signal is sent to an on-board computer to
carry out the required action.
15
Dialogue-based vs. Gesture-based Interfaces
Interface
Advantages
Disadvantages
Dialoguebased
Interface
• no need for a driver to take their hands • still unreliable, with many commands
off the steering wheel
not being recognized or needing to be
• in home, very useful for people with
repeated several times (especially if
disabilities, because many tasks can
there is background noise)
be carried out by spoken word only
• can be quite complex to set up
• possible to use as a security feature,
• user needs to know which commands
because voice recognition could be
can be used
used to identify a person
Gesturebased
Interface
• replaces mechanical input devices
• no physical contact required
• very natural interface for a human
operator
• no training needed to interface with
the computer
• possible for unintentional movement
to be picked up
• only works fairly near to the camera or
sensor (maximum of 1.5 meters)
• may only accept a limited number of
movements (for example, it may take
several attempts to find out exactly 16
what finger movements are
recognized)
Are you in favor
of self driving
cars? Explain
why or why not?
17
Answer theory
workbook Q#4,
Q#10DE on pages 6 and
11.
4mins
Pair with your
seatmates, and
discuss your
answers.
2MINS
Volunteers will be
called to answer
the questions
Answer Q#6 on
page 8 of your
theory WB.
22
HAND ASSESSMENT
5 –I learn everything, everything is clear
4 – I learn some, but there are few which are unclear
3 – I learn few, and there are some which are unclear
2- I learn very few and there are a lot which are unclear
1- I learn nothing and lesson should be repeated
I CARE WHY?
Explain the importance of
operating system.