Introduction to Computers
&
Computer Types
Md Fazlul Kader, Assistant Professor
Dept. of APECE, Faculty of Engineering
University of Chittagong
An Overview of the Computer System
What is a Computer? A computer is an electronic device used to process
data.
A computer can convert data into information that is useful to people.
A complete computer system includes four distinct parts:
Hardware
Software
Data
User
3
A computer is an electronic machine that can be programmed to accept
data (input), process it into useful information (output), and store it in a
storage media for future use
System Unit
What is a Computer?
Block Diagram of Computer
Basic Terminology
Input Whatever is put into a computer system.
Data Refers to the symbols that represent facts, objects, or ideas.
Information The results of the computer storing data as bits and bytes; the words,
numbers, sounds, and graphics.
Output Consists of the processing results produced by a computer.
Processing Manipulation of the data in many ways.
Memory Area of the computer that temporarily holds data waiting to be
processed, stored, or output.
Storage Area of the computer that holds data on a permanent basis when it is
not immediately needed for processing.
An Overview of the Computer System
Hardware
Hardware
Includes the electronic and mechanical devices
that process the data; refers to the computer as
well as peripheral devices.
A computer's hardware consists of electronic
devices; the parts we can see and touch.
The term "device" refers to any piece of
hardware used by the computer, such as a
keyboard, monitor, modem, mouse, etc.
Hardware
Software
Software
A computer program that tells the computer
how to perform particular tasks.
Software – also called programs – consists of
organized sets of instructions for controlling the
computer.
Some programs exist for the computer's use, to help it
manage its own tasks and devices.
Other programs exist for the user, and enable the
computer to perform tasks for you, such as creating
documents.
Data
Raw, unprocessed facts
Processing creates information
Stored electronically in files
Document files
Worksheet files
Database files
Presentation files
Presentation
Database
Worksheet
Document
Users
People are the computer's operators, or
users.
Some types of computers can operate without
much intervention from people, but personal
computers are designed specifically for use
by people.
Types of Computers
Classification of computer depending on signal /
nature of I/O
Computers can also be divided into three
categories depending upon their instruction
and form of input data that they accept and
process. These are:
Analog Computers
Digital Computers
Hybrid Computers
Analog Computers
The word “Analog” means continuously
varying in quantity.
The analog computers accept input data in
continuous form and output is obtained in the
form of graphs.
These computers accept input and give
output in the form of analog signals. The
output is measured on a scale.
These are used in industrial units to control
various processes and also used in different
fields of engineering
Analog Computers
Digital Computers
The word “Digital” means discrete. It refers to binary system, which consists of only two digits, i.e. 0 and 1. Digital data consists of binary data represented by OFF (low) and ON (high) electrical pulses. These pulses are increased and decreased in discontinuous form rather than in continuous form.
The main features of the computers are:
Give accurate result.
Having high speed of data processing.
Can store large amount of data.
Easy of program and are general purpose in use.
Consume low energy.
Hybrid Computers
The hybrid computers have best features of both analog and digital computers.
These computers contain both the digital and analog components. In hybrid computers, the users can process both the continuous (analog) and discrete (digital) data.
These are special purpose computers. These are very fast and accurate.
These are used in scientific fields. In hospitals, these are used to watch patient’s health condition in ICU (Intensive Care Unit). These are also used in telemetry, spaceships, missiles etc.
Hybrid Computers
Differentiate between Analog and Digital Computers
Types of Computers on the basis of size and
capacity
Supercomputers
Mainframe Computers
Minicomputers
Workstations
Microcomputers,
or Personal Computers
Wearable computer
Supercomputers are the most
powerful computers. They are
used for problems requiring
complex calculations.
Because of their size and
expense, supercomputers are
relatively rare.
Supercomputers are used by
universities, government
agencies, and large businesses
Typical uses
Breaking codes
Modeling weather
systems
Supercomputers
"FLOPS" (FLoating Point Operations Per
Second), commonly used with an SI prefix
such as tera-, combined into the shorthand
"TFLOPS" (1012 FLOPS, pronounced
teraflops),
or peta-, combined into the shorthand
"PFLOPS" (1015 FLOPS, pronounced
petaflops.)
Mainframe Computers
Occupies specially wired, air-conditioned rooms
Capable of great processing speeds and data
storage
Not as powerful as supercomputers
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Mainframe
Large expensive computer capable of simultaneously processing data for hundreds or thousands of users.
Used to store, manage, and process large amounts of data that need to be reliable, secure, and centralized.
Usually housed in a closet sized cabinet.
Minicomputers
Known as midrange computers
Used by medium-size companies
Used by departments of large companies
Minicomputers are smaller than mainframes but larger than microcomputers.
Minicomputers usually have multiple terminals.
Minicomputers may be used as network servers and Internet servers.
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Microcomputers
Least powerful
Widely used
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Microcomputer
A personal computer;
designed to meet the
computer needs of an
individual.
Provides access to a
wide variety of
computing applications,
such as word
processing, photo
editing, e-mail, and
internet.
Four Types of Microcomputers
Desktop
Notebook or laptop
Tablet PC
Handheld
Desktop Notebook
Tablet PCHandheld
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1.Desktop Microcomputer
A microcomputer that fits on a desk and runs on power from an electrical wall outlet.
The CPU can be housed in either a vertical or a horizontal case.
Has separate components (keyboard, mouse, etc.) that are each plugged into the computer.
2.Laptop Computer
A portable, compact computer that can run on an electrical wall outlet or a battery unit.
All components (keyboard, mouse, etc.) are in one compact unit.
Usually more expensive than a comparable desktop.
Sometimes called a Notebook.
3.Tablet PC
Is a type of notebook computer that
accepts your handwriting. This input is
digitized and converted to standard text
that can be further processed by
programs such as a word processor.
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4.Handheld
Also called a PDA (Personal
Digital Assistant).
A computer that fits into a
pocket, runs on batteries,
and is used while holding the
unit in your hand.
Typically used as an
appointment book, address
book, calculator, and
notepad.
Can be synchronized with a
personal microcomputer as a
backup.
Handheld
Are the smallest and are also known as
palm computers. These systems typically
combine pen input, writing recognition,
personal organizational tools, and
communications capabilities.
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Microcomputer Hardware
System unit
Input/output devices
Secondary storage
Communications
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Workstation
Powerful desktop computer designed for specialized tasks.
Can tackle tasks that require a lot of processing speed.
Can also be an ordinary personal computer attached to a LAN (local area network).
Workstations are powerful single-user computers.
Workstations are used for tasks that require a great deal of number-crunching power, such as product design and computer animation.
Workstations are often used as network and Internet servers.
Workstation
Wearable computer
Wearable computers are computers that are worn on the body.
This type of wearable technology has been used in behavioral modeling, health monitoring systems, information technologies and media development.
Wearable computers are especially useful for applications that require computational support while the user's hands, voice, eyes, arms or attention are actively engaged with the physical environment.
Wearable computer
Wearable computer
Types of Computers on the basis of purpose
General purpose
Special purpose
General Purpose Computers
General-purpose computers are designed to solve a large variety of problems. That is they can be given different programmes to solve different types of problems.
General-purpose computers can process business data as readily as they process complex mathematical formulas. General-purpose computers can store large amount of data and the programmes necessary to process them.
Because general-purpose computers are so versatile, most businesses today use them. Most digital computers are general computers and it is mainly such computers that are used in business and commercial data processing.
Special Purpose Computers
Special purpose computers are designed to solve a specific problems; the computer programme for solving the problem is built right into the computer.
Special purpose computers have many features of general-purpose computers but are designed to handle specific problems and are not applied to other computerized activities.
For example, special purpose computers may be designed to process only numeric data or to completely control automated manufacturing processes. Moat analogue computers are special purpose computers.
Server
Purpose is to “serve.”
A computer that has the
purpose of supplying its
users with data; usually
through the use of a
LAN (local area
network).
•designed to support a computer network that allows you to share
files, application software, hardware, such as printers and other
network resources.
•Mainframes, personal computers can be used as a server.
•Server computers usually have following characteristics:
•Designed to be connected to one or more networks
•The most powerful CPUs available
•Multiple CPUs to share the processing tasks
•Large memory and disk storage
•High-speed communications capabilities
Servers
