Introduction to computer
Applications Technology
What is CAT
 Computer Applications Technology is the study of
practical techniques for the efficient use of computers
and computer software applications to accomplish
common workplace tasks.
 You will learn how to apply your knowledge and the skills
you gain to solve everyday problems. The solutions
involve the use of either computers and software
applications, or computers and telecommunication
systems, or both.
What is a computer
 A computer is an electronic device which accepts data from he
user stored in memory perform mathematical as well as logical
operation and gives the required results or information.
 A computer is a very smart device that runs on electricity
 A computer is a programmable machine that works on the
instruction given by the user.
 The computer runs only by the combination of hardware and
software.
Overview of the different types of
computers:
 Personal Computer
A personal computer (PC) is a small computer that uses a
microprocessor as its central processing unit (CPU). Desktop
computers, laptop computers, tablet computers and personal digital
assistants (PDA) are different forms of the PC.
Workstation Computer
 Workstation is a high-performance computer system that is basically
designed for a singe user and has advanced graphics capabilities
large storage capacity and a powerful central process unit
 Workstations are used primarily to perform computationally intensive
scientific and engineering tasks.
 They have operating systems that allow several users to work at the
computer at the same time
 Common Uses for workstation include computer-aided design
(CAD),3D graphics and animation, video and audio production,
weather modeling
servers
 A server is a computer that serves information to other computers and
these computers are called clients
 Clients can connect to a sever through either a local area network, or a
wide area network such as internet
 Any computer running the right software can be a server
 Examples include web servers, database server, file server
Mainframes
 A mainframe computer informally called the iron computer is used primary
by large organization for critical applications like bulk data processing for
tasks such censuses, consumer statistics ,enterprise resource planning and
large scale transcations.
Supercomputers
 A supercomputer is faster and more powerful than a mainframe, and is
used for processor intensive calculations and complex modelling scenarios,
such as weather pattern forecasts or the behaviour of molecules.
Dedicated computers
 ● Dedicated computers are computers designed for one specific
task, rather than for general use. Examples of dedicated computers
are:
●video game consoles
●automatic teller machines (ATMs)
●embedded computers in household appliances, such as television
sets, dishwashers and microwave ovens.
Overview and concepts of the main
components of a computer system:
Hardware and software
Hardware includes physical parts of a
computer eg CPU, Keyboard, Mouse etc
Software includes an interface between
the user and the computer eg windows,l
inux, Mac Os etc
Overview and concepts of the main components
of a computer system:
 A computer device is made up of various elements
which help in its effective functioning and processing
 There are five basic components of the computer which
help in making this processing of data easier and
convenient.
 By definition components of a computer system are the
primary elements which make the functioning of an
electronic device smooth and faster. Thus input unit,
output unit, memory unit, control unit and arithmetical
and logical unit
Overview and concepts of the main
components of a computer system:
 Input unit
 A computer will only respond when a command is
given to the device. These commands can be given
using the input unit or the input device
 For example using a keyboard we can type things
on a Notepad and the computer process the
entered data and then displays the output on the
screen.
Overview and concepts of the main
components of a computer system:
 Output
 When we command a computer to perform a task it
reverts for the action performed and gives us a result
and this result is called output
 There are various output device that can be connected
to the computer eg monitor
 Example when we visit an ATM, we enter our details like
language ,pin, amount to be withdrawn etc and then
the final money which the cash dispenser releases is
outcome . In this case the cash dispenser is the output
device
Overview and concepts of the main
components of a computer system:
 Memory unit
 When we enter the data into the computer using an input device , the
entered information immediately gets saved in the memory unit of the
Central Processing Unit (CPU)
 Similarly ,when the output of our command is processed by the computer, it
is saved in the memory unit before giving the output to the user
Overview and concepts of the main
components of a computer system:
 Control Unit
 The control unit collects the data entered using the input unit, leads it on for
processing and once that is done ,receives the output and presents it to
the user
 It can be said to be the center of all processing actions taking place inside
a computer device
Overview and concepts of the main components
of a computer system:
 Arithmetic & Logical Unit
 As the name suggest all the mathematical calculation or arithmetic
operations are performed in the Arithmetic and logical unit of the CPU.
 It can also preform actions like a comparison of data and decision-making
actions
 The ALU comprises circuits using which addition, subtraction, multiplication,
division and other numerical based calculations can performed
Overview and concepts of the main components
of a computer system:
 Central Processing Unit
 The CPU is the core of any computer devices. It comprises three major
components of the computer which have been discussed above
o Memory unit
o Control unit
o Arithmetic and logical unit
ICTs used in everyday life:
 The ICT system refers to the overall set-up, consisting of hardware,
software, data and the people that use it. It commonly includes
communication technology, such as the internet.
 Information and communication technology (ICT) is a field that is
related to computers and communication networks.
 It can also be in the form of audiovisuals, for example, film and digital
productions.
 Digital technologies use data, such as text, numbers, images, sounds
and videos. Computers use this data to show information.
 An ICT system depends on computers, data and people to make the
system work.
 For ICT systems to function correctly, they need to receive, store, retrieve,
manipulate and transmit data.
 Data is often in the form of text, numbers, sounds and images.
EXAMPLE OF AN ICT SYSTEM IN
EVERYDAY LIFE
 Supermarkets and chain stores use ICT systems for a variety of reasons.
 In this example, we will look at the processes of receiving, manipulating, storing
and communicating data at a point-of-sale (POS) system
INPUT AND STORING DATA
 When an item is scanned, the check-out computer checks for the price of
the item in the database. The running total of each item is stored
temporarily in the check-out terminal.
 (There may be other data stored there as well, such as money that was
taken out of the till during the day.)
 MANIPULATING DATA
 After all the items have been scanned, the check-out computer calculates
the data to determine the total cost.
 If the customer pays with cash and requires change, the cashier will enter
the amount given and the check-out computer will calculate any change
that should be given to the customer.
 This is an example of the computer receiving data from the user.
 TRANSMITTING DATA
 When all the items are scanned into the check-out computer, the customer
can see information about the price of each item, which is shown on a
small display.
 After all the items have been scanned, the total amount is shown. The
customer then pays and is given a printed till receipt showing all the items
that were bought and how much each item costs.
 COMMUNICATION
 In some instances, a product’s data can also be sent to the shop’s main
computer for stocktaking purposes, as well as to the manufacturer for their
stock purposes.
Concepts of data and information:
 In computing, it is very important to understand the difference between
data and information. This section will look at the differences between the
two and the importance thereof.
 What do you think of first when you hear the word data? What comes to
mind is raw material, which refers to something that has not yet been
processed.
 Data needs to be processed before it can become useful. Data can be in
the form of text, words, numbers or symbols which, if not put into some type
of context, is pretty useless to us.
 Data is not another word for information.
 Data are the raw materials that are processed to produce information.
 Information is the end result of data processing. In other words, information
is processed data presented in a usable form.
 Accurate and relevant data are essential for producing usable information.
 Managers rely on usable information to make sensible decisions.
The information processing cycle changes data into
information. It consists of:
 ● ●input – the data that goes into a computer
 ● ●processing – the act of manipulating data with a computer to change it
into information
 ● ●output – the information that a computer produces as a result of
processing, usually in the form of an on-screen display or printout
 ● ●storage – computers may store data before or during the processing
and generally store the information produced.
 Tables 1.1 and 1.2 show the difference between data and information. In
Table 1.1, we cannot see how the learners are performing.
 However, after the computer manipulated the test scores, we are given
meaningful information, as can be seen in Table 1.2. Remember, the
information we get out of a computer is only as good as the data that is
entered into it.
THE GIGO PRINCIPLE
 GIGO is an acronym for Garbage In, Garbage Out. Simply put, it
means that bad input will result in bad output.
 It is very important to remember the GIGO principle, because bad
data will give you bad information.
 Using the example of the learners’ test results, if the teacher entered
the incorrect marks into the computer (i.e. bad data), the
information that she would get as a result, will also be incorrect.
 It is quite possible for data to be interpreted incorrectly. This is often
the result of incorrect or incomplete data, or a lack of context.
THE INFORMATION-PROCESSING CYCLE