Chapter1 fundamentals of computers by reema thareja

Fundamentals of
Computers
Reema Thareja
© Oxford University Press 2016. All rights reserved.

Chapter 1Chapter 1
Introduction toIntroduction to
ComputersComputers

A computer, in simple terms, can be defined as an electronic device
which accepts data, performs the required mathematical and logical
operations at high speed, and outputs the result.
What is a Computer?

• Computer accepts data, processes it, and produces information.
• Data refers to some raw facts or figures, and information implies
the processed data.
• For example, if 12-1-96 is the date of birth of a student, then it is
data (a raw fact/figure). However, when we process this data
(subtract it from the present date) and say that the age of the
student is 18 years, then the outcome is information.
ProcessData Information
Data and Information

Speed: Computers can perform millions of operations per second. The
speed of computers is usually given in nanoseconds (ns) and picoseconds
(ps), where 1 ns = 1×10-9
sec and 1 ps = 1×10-12
sec.
Versatile: Computers can perform multiple tasks of different nature at the
same time.
Memory: Computers have internal or primary memory (storage space) as
well as external or secondary memory to store data and programs.
Characteristics of Computers

Accuracy: A computer always gives accurate results, provided the
correct data and instructions are input to it. If the input data is
wrong, then the output will also be erroneous. This is called
garbage-in, garbage-out (GIGO).
Automation: Computers perform a task without any user
intervention.
Diligence: Unlike humans, computers never get tired of a repetitive
task.

No IQ: Computers do not have any decision-making abilities of
their own. They need guidance to perform various tasks.
Economical: Computers are considered as short-term investments
for achieving long-term gains. They save time, money, and energy.

The word ‘Generation’, when applied to computing, refers to the different
advancements in computer technology.
The focus of every new generation has been on miniaturization, speed,
power, and efficient computer memory.
Generations of Computers

Advantage
 Fastest calculating devices of their time
Disadvantages
 Generated a lot of heat
 Consumed a lot of electricity
 Bulky in size
 Prone to frequent hardware
 Required constant maintenance because of the low mean time
between failures
 Limited commercial use
 Very expensive
First Generation (1940-1956): Vacuum
Tubes

Advantages
 Consumed less electricity
 Generated less heat
 Faster, cheaper, smaller, and more reliable
 Could be programmed using assembly and high-level languages
 Had faster primary memory and a larger secondary memory
Disadvantage
 Transistors had to be assembled manually, which made
commercial production of computers difficult and expensive
Second Generation (1956-1963): Transistors

Advantages
 Faster and could perform one million transactions per second
 Smaller, cheaper, and more reliable
 Faster and larger primary memory and secondary storage
 Widely used for scientific as well as business applications
 Supported time sharing operating systems
Disadvantages
 Difficult to maintain
 Got heated very quickly
Third Generation (1964-1971): Integrated
Circuits

Advantages
 Smaller, cheaper, faster, and more reliable
 Consumed less electricity and generated less heat
 Faster and larger primary memory and secondary storage
 Could be used as general-purpose computers
 GUIs enabled people to learn to work with computers very easily
 Lead to widespread use of computers in offices and at homes
 Networks allowed sharing of resources
Disadvantage
 Not intelligent systems
Fourth Generation (1971-1989): Microprocessors

• Gaming: Computers are programmed to play games such as chess
and checkers. More recent examples of such gaming systems
include PlayStation by Sony.
• Expert systems: Computers are programmed to take decisions in
real-world situations.
• Natural languages: Computers are programmed to understand
and respond to natural human languages.
Fifth Generation (Present and Beyond): Artificial
Intelligence

• Neural networks: Systems are programmed to simulate
intelligence by reproducing the physical connections that take
place in animal brains.
• Robotics: Computers are programmed to look, listen, and react to
other sensory stimuli.
Fifth Generation (Present and Beyond): Artificial
Intelligence

Classification of Computers

Supercomputers
• Fastest, most powerful, and most expensive computer
• Used to process large amounts of data and to solve complex
scientific problems
• Can support thousands of users at the same time
• Mainly used for weather forecasting, nuclear energy research,
aircraft design, automotive design, online banking, etc.
• Some examples of supercomputers are CRAY-1, CRAY-2, Control
Data CYBER 205, and ETA A-10
Supercomputers

Mainframe Computers
• Large-scale computers, but smaller than Supercomputers
• Very expensive
• Need a very large clean room with air conditioning
• Used as servers on the World Wide Web
• Some examples are IBM S/390, Control Data CYBER 176, and
Amdahl 580
Mainframe Computers

Mini Computers
• Smaller, cheaper, and slower than Mainframes
• Can be used as servers in a networked environment
• Widely used in business, education, hospitals, government
• Some examples are AS/400 computers (IBM Corporation),
Data General Corporation, and Prime Computer
Minicomputers

Microcomputers
Desktop PCs
• Most popular model
• Widely used in homes and offices
Laptops
• Very handy and easily portable
• Storage capacity is almost equivalent to that of a desktop computer
• For input, laptops have a built-in keyboard and a touchpad
• More expensive than desktop computers
Microcomputers

Workstations
• Single-user computers
• Same features as PCs but with higher processing speed
• Have advanced processors, more RAM and storage capacity
• Can be used as servers in a networked environment
Microcomputers

Network Computers
• Designed to be used as terminals in a networked environment
• Have less processing power, memory, and storage
• Those used to access Internet or Intranet are often known as
Internet PCs or Internet boxes
• Some used in homes do not even have a monitor. They may be
connected to a TV. They are called WebTV
Microcomputers

Handheld Computers
• Single-user computers
• Can fit in one hand
• Have small-sized screens and keyboards
• Some examples of handheld computers are
 Personal Digital Assistants (PDA)
 Cellular Phones
 H/PC Pro Devices
Microcomputers

Basic Organization of Computers

• Input: The process of entering data and instructions (also known
as programs) into the computer system
• Storage: The process of saving data and instructions
permanently in the computer so that they can be used for
processing. A computer has two types of storage areas:
Primary storage (main memory) is the storage area that is
directly accessible by the CPU at very high speeds
Secondary storage (secondary or auxiliary memory)
supplements the limited storage capacity of the primary
memory

• Processing: The process of performing operations on the data
as per the instructions specified by the user (program)
• Output: The process of giving the result of data processing to
the outside world (external to the computer system)
• Control Unit: It is the central nervous system of the computer
system that manages and controls all the other components

•Word Processing
•Internet
•Digital Video or Audio
Composition
•Desktop Publishing
•Government/Administration
Applications of Computers
•Traffic Control
•Legal System
•Retail Business
•Sports
•Music
•Movies
•Travel and Tourism

•Business and Industry
•Hospitals
•Simulation
•Geology
•Astronomy
•Weather Forecasting
•Education
•Online Banking
•Industry and Engineering
•Robotics
•Decision Support Systems
•Expert Systems
Applications of Computers

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