This document discusses the components and functions of a basic computer system. It describes how a computer system consists of hardware and software. The key hardware components are the central processing unit (CPU), memory (RAM and ROM), and input/output interfaces. The CPU contains the arithmetic logic unit, control unit, and storage unit. It interprets and executes instructions to perform operations on data. The control unit manages data transfer between components. Memory stores instructions, data, and results. Software enables interaction with the hardware and allows computers to perform tasks. A computer system gathers data as input, processes it, outputs information, and stores data/information in memory.

1. L E C T U R E 2
O C T O B E R , 2 0 1 8
IT in Business - I

2. IT and Computing
Produces and stores results
Electronic device operating under the control of
instructions stored in its own memory
Processes data into
information
Data that is organized,
meaningful, and useful
Accepts data
Raw facts, figures, and
symbols

3. The Components of a Computer
 A computer contains many electric, electronic, and mechanical
components known as hardware
• Allows you to enter data and instructions into a computerInput Device
• Hardware component that conveys information to one or more peopleOutput Device
• Case that contains the electronic components of the computer that are used to process dataSystem Unit
• Records (writes) and/or retrieves (reads) items to and from storage mediaStorage Device
• Enables a computer to send and receive data, instructions, and information to and from one or more
computers or mobile devices
Communications
Device

4. Types Of Computers
(by Functionality)
Analog Computers
 An analog Computer does not operate with digital signals.
 It recognizes data as a continuous measurement of a physical
property.
 It has no state. Analog computer is difficult to operate and use.
 Voltage ,pressure, speed and temperature are some physical properties
that can be measured in this way.
 Analog computer is mainly used in the field of engineering and
medicine.

5. Types Of Computers
(by Functionality)
Digital Computers
 A Digital Computer Works with Digits. Everything Is described in two states i.e.
either on or off.
 The number 1 represents on and 0 represents off state. it operates by counting
numbers or digits and gives output in digital form.
 The digital computers are very fast. These computers store result in digital form.

6. Types Of Computers
(by Functionality)
Digital Computer
1. Digital watch is a good example of digital
computer.
2. Score board that directly count discrete values such
as the time left to play and the score of each team.

7. Types Of Computers
(by Functionality)
Hybrid Computers:
 These types of computers are, as the name suggests, a combination of both Analog and Digital
computers.
 A hybrid computer combines the best characteristics of both the analog and digital computer.
 It can accept data in analog and digital form.
Examples:
 Hybrid computer devices may calculate patient’s heart function ,temperature, blood pressure etc.

8. Types Of Computers
(by Size)
According to size there are four main
types of computer.
Super Computer
Mini computer
 Main frame
 Micro Computer

9. Types Of Computers
(by Size)
Super Computer:
 Supercomputers are one of the fastest computers currently
available.
 Supercomputers are very expensive and are employed for
specialized applications that require immense amount of
mathematical calculations (number crunching).
 For example, weather forecasting, scientific simulations,
(animated) graphics, fluid dynamic calculations, nuclear energy
research, electronic design, and analysis of geological data (e.g.
in petrochemical prospecting).

10. Types Of Computers
(by Size)

11. Types Of Computers
(by Size)
Mainframe:
 Mainframe is very large in size and is an
expensive computer capable of supporting
hundreds or even thousands of users
simultaneously.
 Mainframe executes many programs
concurrently and supports many
simultaneous execution of programs

12. Types Of Computers
(by Size)
Mini Computer
It is a multi-user computer system which is capable of
supporting hundreds of users simultaneously.
It is a midsize multi-processing system capable of supporting
up to 250 users simultaneously.

13. Types Of Computers
(by Size)
Micro Computer:
 Personal Computer
 Work Station

14. Types Of Computers
(by Size)
Personal Computer
 It is a single user computer system having moderately powerful microprocessor.
 A PC can be defined as a small, relatively inexpensive computer designed for an individual user.
 PCs are based on the microprocessor technology that enables manufacturers to put an entire CPU
on one chip.
 Businesses use personal computers for word processing, accounting, desktop publishing, and for
running spreadsheet and database management applications.
 At home, the most popular use for personal computers is playing games and surfing Internet.

15. Types Of Computers
(by Size)
Work Station
 It is also a single user computer system which is similar to personal computer but have
more powerful microprocessor.
 Workstation is a computer used for engineering applications, desktop publishing,
software development, and other such types of applications which require a moderate
amount of computing power and relatively high quality graphics capabilities.
 Workstations generally come with a large, high-resolution graphics screen, large
amount of RAM, inbuilt network support, and a graphical user interface.
 Most workstations also have a mass storage device such as a disk drive, but a special
type of workstation, called a diskless workstation, comes without a disk drive.

16. Application of Computers

17. Computers have transformed every dimension of human life
Application of Computers
CommunicationEducation
Business
Socialisation
Economy
Health & Medicine
Showbiz IoT

18. Application of Computer
Banking
 Today banking is almost totally dependent on computer.
 Banks provide following facilities:
 Banks provide online accounting facility, which includes current
balances, deposits, overdrafts, interest charges, shares, and trustee
records.
 ATM machines are making it even easier for customers to deal
with banks.

19. Application of Computer
Business
 A computer has high speed of calculation, diligence, accuracy,
reliability, or versatility which made it an integrated part in all business
organizations.
 Computer is used in business organizations for:
 Payroll calculations
 Budgeting
 Sales analysis
 Financial forecasting
 Managing employees database
 Maintenance of stocks etc.

20. Application of Computer
Education
 The computer has provided a lot of facilities in the education system.
 The computer provides a tool in the education system known as CBE (Computer
Based Education).
 CBE involves control, delivery, and evaluation of learning.
 The computer education is rapidly increasing the graph of number of computer
students.
 There are number of methods in which educational institutions can use computer
to educate the students.
 It is used to prepare a database about performance of a student and analysis is
carried out on this basis.

21. Application of Computer
Engineering Design
 Computers are widely used in Engineering purpose.
 One of major areas is CAD (Computer aided design). That provides
creation and modification of images. Some fields are:
 Structural Engineering - Requires stress and strain analysis for design
of Ships, Buildings, Budgets, Airplanes etc.
 Industrial Engineering - Computers deal with design, implementation
and improvement of integrated systems of people, materials and
equipments.
 Architectural Engineering - Computers help in planning towns,
designing buildings, determining a range of buildings on a site using
both 2D and 3D drawings.

22. Following are some important capabilities/
characteristics of Computers:
Speed Storage Capacity
Processing Accuracy
Recalling Control sequence
Consistency Communication
Versatility Cost Reduction

23. Capabilities Of Computers
Speed:
Computers can carry out instructions in less than a millionth of a second. For instant , a
small computer can sort a set of hundred names in less than a hundredth of a second.
Storage Capacity:
Computers have the capacity to store large amounts of instructions and data and supply
stored information to us when we ask for it. This is an advantage over our brains where
it is difficult to store all information we acquire for long time
Processing
A computer can process the given instructions. It can perform different types of
processing like addition, subtraction, multiplication and division. It can also perform
logical Functions like comparing two numbers to decide which one is greater.
Accuracy
Accuracy means to provide result without any error. Computer can process large
amount of data and generate error free results.

24. Capabilities Of Computers
Recalling
A computer can recall the stored data and information as and when
required . The data stored in the computer can be used at a later time.
The computer can recall the data within few seconds .
Control Sequence
A computer works strictly according to the given instructions. It follows
the same sequence of instructions that is given to a Program.
Consistency
Computers works in consistent way. It does not lose concentration due to
heavy work. It does not become tired or bore. Computer performs all
the jobs with equal attention.

25. Capabilities Of Computers
Communication
Most computers have the capability to communicate with other computers. We can connect
two or more computers by Communicating device such as modem. These computers can
share data , instructions and information.
Versatile
A computer can perform different types of tasks. We can use computers in hospitals , banks
or at home. A variety of facilities are available through computers.
Cost Reduction
By using computers we can perform a difficult task in less time and less cost. For example
we may have to hire many persons to handled an office. The same work can be performed
by a single person with the help of computer. It reduce the cost.

26. Limitations Of Computers
We have understood the importance of computer in our lives. Does that means that
a computer act like an Obedient assistant who can perform all tasks repeatedly at
high speed without any error?
Lack of Commonsense
Inability to correct
Dependence on human instructions

27. Components of Computer System

28. Computer System
“A system of interconnected computers that share a
central storage system and various peripheral devices such
as a, keyboard, printers, scanners, each computer connected
to the system can operate independently, but has
the ability to communicate with other external devices and
computers.”

29. Computer System
 Computer system can also define as
“A computer system consists of hardware components that have
been carefully chosen so that they work well together and software
components or programs that run in the computer. The main
software component is itself an operating system that manages and
provides services to other programs that can be run in the computer.”

30. Parts of Computer System
There are two major divisions:
Hardware
Software
Hardware:
 Computer hardware is the collection of physical parts of
a computer system. This includes the computer case,
monitor, keyboard, and mouse.
It also includes all the parts inside the computer case, such as
the hard disk drive, motherboard, video card, and many
others.
Computer hardware is what you can physically touch.

31. Software
 Software:
“software is a collection of instructions that enable the user
to interact with a computer, its hardware, or perform tasks.
Without software, computers would be useless.
 For example, without your Internet browser, you could
not surf the Internet or read this page and without
an operating system, the browser could not run on your
computer. The picture to the right is a Microsoft Excel
software box and an example of a spreadsheet software
program”.

32. Computer System
The Four Main Functions of Computer Systems
Computers are designed to:
Gather data(Input)
Process data (Process)
Output information (Output)
Store data and Information (memory)

33. Computer System

34. CPU
BLOCK DIAGRAM OF A BASIC
COMPUTER SYSTEM
ROM RAM I/O
interface
I/O
devices
Basic computer system consist of a Central processing unit (CPU), memory
(RAM and ROM), input/output (I/O) unit.
Block diagram of a basic computer system
Address bus
Data bus Control
bus

35. CPU (Central Processing Unit)
CPU is also called processor.
It interprets and execute instructions to run
the computer system.
It is also called the brain of computer
It performs all operations on the data
according to the instructions
It carries out instruction and tell other parts of
computer system what to do.

36. CPU(Central Processing Unit)
CPU consists of following units
 ALU(Arithmetic and Logic Unit)
 CU (Control Unit)
 Memory or Storage Unit

37. ALU(Arithmetic and Logic Unit)
This unit consists of two subsections namely
 Arithmetic section
 Logic Section
Arithmetic Section
 Function of arithmetic section is to perform arithmetic operations
like addition, subtraction, multiplication and division. All complex
operations are done by making repetitive use of above operations.
Logic Section
 Function of logic section is to perform logic operations such as
comparing and matching of data.

38. CU (Control Unit)
 This unit controls the operations of all parts of computer but does not carry out any actual data
processing operations.
Functions of this unit are:
 It is responsible for controlling the transfer of data and instructions among other units of a computer.
 It manages and coordinates all the units of the computer.
 It obtains the instructions from the memory, interprets them, and directs the operation of the computer.
 fetching, decoding, managing execution and then storing results
 It communicates with Input/output devices for transfer of data or results from storage.
 It does not process or store data.

39. Memory or Storage Unit
 This unit can store instructions, data and intermediate results.
 This unit supplies information to the other units of the computer when
needed. It is also known as internal storage unit or main memory or
primary storage or Random Access Memory(RAM).
 Its size affects speed, power and capability. Primary memory and
secondary memory are two types of memories in the computer.
Functions of memory unit are:
 It stores all the data and the instructions required for processing.
 It stores intermediate results of processing.
 It stores final results of processing before these results are released to an
output device.
 All inputs and outputs are transmitted through main memory.

41. The CPU Instruction Cycle
 The CPU executes a series of instructions by looping through an
instruction cycle.
The speed of the
instruction cycle
is controlled by
the CPU's clock.