INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGIES.
(Types and Classifications of Computers Lecture # 02
By:
M.Nadeem Akhtar. Lecturer.
Department of CS & IT. Department of CS & IT.
URL:
T
YPES OF
C
OMPUTER
(
O
N THEB
ASIS OFF
UNCTIONALITY)
According to functionality computer can be divided in to three types:
1) Analog
2) Digital
Hybrid
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3) Hybrid
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1-A
NALOG
C
OMPUTER
An analog computer is a form of computer that uses the continuously-changeable aspects of physical
fact such as electrical, mechanical, or hydraulic(moved
or operated or effected by liquid) quantities to model the problem being solved.”
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Analog means continuity of associated quantity just
like an analog clock measures time by means of the distance traveled by the hand of the clock around a dial.
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1-A
NALOG
C
OMPUTER
(C
ONTI
.)
Analog computer measures and answer the questions by the method of “HOW MUCH”. The input data is not a number infect a physical quantity like temperature, pressure, speed, velocity
Used in World War II and the Korean War.
They were commonly used in science and industry
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They were commonly used in science and industry before the Digital Computer
EXAMPLES:
Thermometer Analog clock Speedometer
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2-D
IGITAL
C
OMPUTERS
.
“A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system of “0” and “1”. “Computer capable of solving problems by processing information expressed in discrete form.
Digital computer counts and answer the questions
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Digital computer counts and answer the questions by the method of “HOW Many”. The input data is represented by a number. These are used for the logical and arithmetic operations.
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2-D
IGITAL
C
OMPUTERS
(C
ONTI
.)
By manipulating combinations of binary digits (“0”, “1”)
o Mathematical calculations
o Organize and analyze data
Control industrial and other processes.
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o Control industrial and other processes.
EXAMPLES:
IBM PC
Apple Macintosh Calculators
Digital watches etc
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3-H
YBRID
C
OMPUTERS
:
o “A computer that processes both analog and digital
data”.
o “Hybrid computer is a digital computer that accepts
analog signals, converts them to digital and processes them in digital form”
o Hybrid Machines are generally used in scientific
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o Hybrid Machines are generally used in scientific
applications or in controlling industrial processes.
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3-H
YBRID
C
OMPUTERS
:
Examples:
Hybrid computer is the computer used in
hospitals to measure the heartbeat of the patient. Radar is also an example of hybrid computer
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C
LASSIFICATION OFC
OMPUTERS.
(ON THE BASIS OF SIZE CAPACITY AND SPEED)
On the basis of size capacity and speed,
Computers can be divided into following four classifications:
1) Super Computers.
2) Main frame Computers.
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2) Main frame Computers.
3) Mini frame Computers.
4) Micro Computers.
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1-SUPER COMPUTERS.
Leads the world in terms of processing capacity, particularly speed of calculation
Can handle gigantic amount of scientific computation About 50,000 times faster than micro-computers
Used primarily for engineering and scientific problem analysis as well as for computerized graphics and
special effects seen in films.
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special effects seen in films.
Cost as much as $20 million
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A super computer contains a number of CPU which operate in parallel to make it faster. It also known as grand father computer.
In areas like:
Defense(Missile Technology)
1-SUPER COMPUTERS.(Conti.)
Defense(Missile Technology) Weather forecasting
Scientific research Drug discoveries
Hollywood movies
2-M
AIN FRAMEC
OMPUTERSSmaller and less powerful than supercomputer
Can support hundreds and thousands of users
used mainly by large used mainly by large
organizations for critical
applications, typically bulk data processing(i.e. huge storage
2-M
AIN FRAMEC
OMPUTERS(C
ONTI.)
These are large and fast computers usually housed in a controlled environment.
Multi-user environment, have the ability to service more than 100 terminals at a time
TERMINALS – are the points from which users can have access to the services of a multi-user computer.
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computer.
Terminals (which look like a microcomputer) are used to enter and retrieve data from mainframe computers.
They can support the processing requirements of hundreds and even thousands of users.
Are the largest, fastest and most expensive computers in commercial use today.
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Of all types of computers, mainframe have been around the longest. ENIAC(Electronic Numerical Integrator
And Calculator) and UNIVAC(Universal Automatic
Computer) were mainframe computers.
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2-Main frame Computers. (Conti.)
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3-M
INIC
OMPUTERS.
Is the smallest computer designed specifically for the multi-user environment.
This type of computer can allow several persons to use the
machine at the same time. Can process up to millions of characters.
characters.
Before the late 60’s, most computers produced were
mainframe computers and they were very expensive.
The prohibited price of
A smaller and more affordable version of mainframe and thus what the minicomputer was born.
Their storage capacities are smaller and they service fewer terminals as compared to mainframes.
A computer servicing more than 100 terminals is no longer called a minicomputer.
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3-Mini Computers.(Conti.)
longer called a minicomputer.
The major difference between the mainframe and
minicomputer is in the number of terminals they can service.
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4-M
ICROC
OMPUTERS.
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
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as word processing, photo editing, e-mail, and internet.
The major difference between microcomputers and the larger minicomputers and mainframes is that micros are generally single-user but a multi-tasking machine.
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4-M
ICROC
OMPUTERS.(C
ONTI.)
Personal Computers (PC)
occupy physically small
amounts of space
Low Power Consumption
Example:
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Example:
Desktop computers laptop computers handhelds
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4-M
ICROC
OMPUTERS.(C
ONTI.)
DESKTOP MICROCOMPUTERBigger in Size No Portability Input & Output
devices are connected separately to System Unit
separately to System Unit
Has separate
components (keyboard, mouse, etc.) that are each plugged into the computer.
4-M
ICROC
OMPUTERS.(C
ONTI.)
L
APTOPC
OMPUTERA portable, compact computer that can run on an electrical wall outlet or a battery unit. All components
(keyboard, mouse, etc.) are in one compact
(keyboard, mouse, etc.) are in one compact
unit.
Usually more
expensive than a comparable desktop. Sometimes called a Notebook.
4-MICRO COMPUTERS.(CONTI.)
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.
Smaller in Size and Fully Portable
Portable
Speed is less than Desktops & Laptops
Capable of running specific Application Software (System Software are limited)
Can operate for days on its batteries.
4-M
ICROC
OMPUTERS.
(C
ONTI.)
T
ABLETPC.
A tablet PC is a wireless personal computer (PC) that allows a user to
take notes using natural handwriting with a
stylus or digital pen on a touch screen.
The user's handwritten The user's handwritten notes, which can be
edited and revised, can also be indexed and
searched or shared via e-mail or cell phone. Touch Panel with
Workstations are similar like Desktop PCs but unlike desktops, they have high end processing speed for
specific software
Used for Graphic Designing, Special effects for movies, CAD applications
Special Input and Output devices are provided to Power Users
4-Micro Computers.(Conti.)
Workstation
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Special Input and Output devices are provided to Power Users
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E
MBEDDEDC
OMPUTERS.
An embedded computer is a special-purpose computer
that functions as a component in a larger product
S
ERVERSA server is a large shared computer
several times the power of a workstation several times the memory of a workstation hardware and operating system optimised
for multi-user, no-crash operation
A server may act as one or more of functions like:
compute server: to run programs
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compute server: to run programs file server: to store files centrally mail server: to route mail messages web server: to store web files etc Print server: to print the document
Proxy server: to provide internet access.
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