System, sub-system, computer system, advantages, disadvantages, types of computers, classes by size and functions, server, workstations, information appliances, embedded computers etc.

1. Introduction to computer
IT-101
Lecture #1

2. System
Def #1:
• A set of detailed methods, procedures, and
routines established or formulated to carry
out a specific activity, perform a duty, or solve
a problem.
Def #2:
• A group of interacting, interrelated, or
interdependent elements forming a complex
whole.

3. Sub-system
• A major part of a system which itself has the
characteristics of a system, usually consisting
of several components.

4. Computer System
• A complete, working system. Computer
systems will include the computer along with
any software and peripheral devices that are
necessary to make the computer function.
Every computer system, for example, requires
an operating system.

5. Computer System

6. Why we use Computers ?
Why we need IT ?

7. Introduction to Computer
• An electronic device designed to accept data,
perform prescribed mathematical and logical
operations at high speed, and display the
results of these operations.

8. Advantages
• It helps you automate various tasks that you
cannot do manually.
• It helps you organize your data and
information in a better way.
• It has much more computing and calculating
power then an ordinary human.
• It may help your work to be a lot easier.
• It may be the storage of your important data
and files.

9. Advantages
• It may be your handy book.
• It may help you solve problems faster than an
ordinary human being can do.
• It has speed, storage, reliability, consistency
and communications.
• It helps you to find useful information using
the Internet.
• It helps in businesses, factories, offices,
schools and homes.

10. Disadvantage
• It destroys your social life and interactions with
humans if you do not maintain the balance.
• It may effect to the destruction of your eye sight
due to radiation.
• It may cause pimples and wrinkles.
• It may damage your studies and life.
• Too much time in front of monitor may adverse
effect your eye sight and can also make you fat.

11. Disadvantage
• The way it distracts and can deviate our thoughts
and activities towards unproductive activities.
• It could cause violation of privacy, impact on
labor force, health risks, impact on environment,
distraction from work, and possible antisocial
influences.
• Getting away from their real life and getting into
bad lines.

12. Types of Computer
Computer types can be divided into 3 categories
according to electronic nature.
• Analog Computer
• Digital Computer
• Hybrid Computer

13. Analogue Computer
• Analogue types of Computer uses what is
known as analogue signals that are
represented by a continuous set of varying
voltages and are used in scientific research
centers.

14. Digital Computer
• A computer that stores data in terms of digits
(numbers) and proceeds in discrete steps from
one state to the next. The states of a digital
computer typically involve binary digits which
may take the form of the presence or absence
of magnetic markers in a storage medium. In
digital computers, even letters, words and
whole texts are represented digitally.

15. Hybrid Computers
• Hybrid computers are the form of computers
which had been designed to display the features
and characteristics of both computers which are
the analog and the digital computers. When the
hybrid computers are used in the form of digital
computers then they are deigned to act as the
controller for the operations carried out in the
system. When analog is taken into account then
in that case the computer acts as a solution
provider for different problems that exit and thus
by depicting both the feature, it is found to be a
beneficial computer.

16. Classification of Computer
• There are two types of classes
• Classes by size
• Classes by Functions

17. Classes by size
• Microcomputers (Personal computers)
• Minicomputers (Midrange computers)
• Mainframe computers
• Supercomputer

18. Classes by functions
• Servers
• Workstations
• Information appliances
• Embedded computers

19. Microcomputers
• Microcomputers are the most common type of
computers used by people today, whether in a
workplace, at school or on the desk at home. E.g.:
• Desktop computers
• Game consoles Laptops
• Notebook computers
• Palmtop computers
• Tablet PC
• Programmable calculator

20. Minicomputers (Midrange computers)
• A minicomputer is a class of multi-user
computers that lies in the middle range of the
computing variety, in between the smallest
multi-user systems (mainframe computers)
and the largest single-user systems
(microcomputers or personal computers ).

21. Minicomputers (Midrange computers)
• Computer that possesses the same
components as large mainframes but has
reduced memory and slower processing
speeds.
• Contemporary term for this class of system is
midrange computer, such as the higher-end
SPARC, POWER and Itanium -based systems
from Sun Microsystems, IBM and Hewlett-
Packard.

22. Mainframe Computers& Supercomputer
• A very large and expensive computer capable of
supporting hundreds, or even thousands, of users
simultaneously. In the hierarchy that starts with a
simple microprocessor (in watches, for example) at the
bottom and moves to supercomputers at the top,
mainframes are just below supercomputers.
• In some ways, mainframes are more powerful than
supercomputers because they support more
simultaneous programs. But supercomputers can
execute a single program faster than a mainframe. The
distinction between small mainframes and
minicomputers is vague, depending really on how the
manufacturer wants to market its machines.

23. Servers
• Server is a physical computer (a hardware
system) dedicated to running one or more
such services (as a host) to serve the needs of
users of the other computers on the network.
Depending on the computing service that it
offers it could be a database server, file server,
mail server, print server, web servers, or other.

24. Workstations
• In networking, workstation refers to any
computer connected to a local-area network.
It could be a workstation or a personal
computer.

25. Information Appliance
• In information appliance or information
device is any machine or device that is usable
for the purposes of computing,
telecommunicating, reproducing, and
presenting encoded information in myriad
forms and applications.

26. Information Appliance
• “Information Appliance" (IA) is more specific
an appliance that is specially designed to
perform a specific user-friendly function such
as playing music, photography, or editing text.
• Smart Phones
• Personal Digital Assistants (PDAs)

27. Embedded Computers
• Embedded computers can be compared to
"computers on a chip". All in one so to speak.
You will find them in all kind of appliances that
surround us. Washing machines, ticket
machines at the subway, camera's, cars,
motors, sewing machines, clocks. Everywhere
needing something to regulate, control of
check something.