Unit 1
INTRODUCTION TO COMPUTER
Computer is an electronic device that operates (works) under the control of programs stored in its
own memory unit.
A computer is an electronic machine that processes raw data to give information as output.
An electronic device that accepts data as input, and transforms it under the influence of a set of
special instructions called Programs, to produce the desired output (referred to as Information).
Data: Is a collection of raw facts, figures or instructions that do not have much meaning to the user.
Data may be in form of numbers, alphabets/letters or symbols, and can be processed to produce
information.
TYPES OF DATA.
There are two types/forms of data:
a). Digital (discrete) data:
Digital data is discrete in nature. It must be represented in form of numbers, alphabets or symbols
for it to be processed by a computer. Digital data is obtained by counting. E.g. 1, 2, 3 …
b). Analogue (continuous) data:
Analogue data is continuous in nature. It must be represented in physical nature in order to be
processed by the computer. Analogue data is obtained by measurement. E.g. Pressure,
Temperature, Humidity, Lengths or currents, etc. The output is in form of smooth graphs from which
the data can be read.
CHARACTERISTICS OF COMPUTER:
The characteristics of the computer system are as follows −
Speed
A computer works with much higher speed and accuracy compared to humans while
performing mathematical calculations. Computers can process millions (1,000,000)
of instructions per second. The time taken by computers for their operations is
microseconds and nanoseconds.
Accuracy
Computers perform calculations with 100% accuracy. Errors may occur due to data
inconsistency or inaccuracy.
Diligence
A computer can perform millions of tasks or calculations with the same consistency
and accuracy. It doesn’t feel any fatigue or lack of concentration. Its memory also
makes it superior to that of human beings.
Versatility
Versatility refers to the capability of a computer to perform different kinds of works
with same accuracy and efficiency.
Reliability
A computer is reliable as it gives consistent result for similar set of data i.e., if we
give same set of input any number of times, we will get the same result.
Automation
Computer performs all the tasks automatically i.e. it performs tasks without manual
intervention.
Memory
A computer has built-in memory called primary memory where it stores data.
Secondary storage are removable devices such as CDs, pen drives, etc., which are
also used to store data.
History of Computers
People used sticks, stones, and bones as counting tools before computers were
invented. More computing devices were produced as technology advanced and the
human intellect improved over time. Let us look at a few of the early-age
computing devices used by mankind.
1. Abacus
Abacus was invented by the Chinese around 4000 years ago. It’s a wooden rack
with metal rods with beads attached to them. The abacus operator moves the beads
according to certain guidelines to complete arithmetic computations.
2. Napier’s Bone
John Napier devised Napier’s Bones, a manually operated calculating apparatus.
For calculating, this instrument used 9 separate ivory strips (bones) marked with
numerals to multiply and divide. It was also the first machine to calculate using the
decimal point system.
3. Pascaline
Pascaline was invented in 1642 by Biaise Pascal, a French mathematician and
philosopher. It is thought to be the first mechanical and automated calculator. It was
a wooden box with gears and wheels inside.
4. Stepped Reckoner or Leibniz wheel
In 1673, a German mathematician-philosopher named Gottfried Wilhelm Leibniz
improved on Pascal’s invention to create this apparatus. It was a digital mechanical
calculator known as the stepped reckoner because it used fluted drums instead of
gears.
5. Difference Engine
In the early 1820s, Charles Babbage created the Difference Engine. It was a
mechanical computer that could do basic computations. It was a steam-powered
calculating machine used to solve numerical tables such as logarithmic tables.
6. Analytical Engine
Charles Babbage created another calculating machine, the Analytical Engine, in
1830. It was a mechanical computer that took input from punch cards. It was
capable of solving any mathematical problem and storing data in an indefinite
memory.
7. Tabulating machine
An American Statistician – Herman Hollerith invented this machine in the year
1890. Tabulating Machine was a punch card-based mechanical tabulator. It could
compute statistics and record or sort data or information. Hollerith began
manufacturing these machines in his company, which ultimately became
International Business Machines (IBM) in 1924.
8. Differential Analyzer
Vannevar Bush introduced the first electrical computer, the Differential Analyzer,
in 1930. This machine is made up of vacuum tubes that switch electrical impulses
in order to do calculations. It was capable of performing 25 calculations in a matter
of minutes.
9. Mark I
Howard Aiken planned to build a machine in 1937 that could conduct massive
calculations or calculations using enormous numbers. The Mark I computer was
constructed in 1944 as a collaboration between IBM and Harvard.
GENERATIONS OF COMPUTER
The modern computer took its shape with the arrival of your time. It had been
around 16th century when the evolution of the computer started. The initial
computer faced many changes, obviously for the betterment. It continuously
improved itself in terms of speed, accuracy, size, and price to urge the form of the
fashionable day computer. This long period is often conveniently divided into the
subsequent phases called computer generations:
First Generation Computers (1940-1956)
Second Generation Computers (1956-1963)
Third Generation Computers (1964-1971)
Fourth Generation Computers (1971-Present)
Fifth Generation Computers (Present and Beyond)
First Generation Computers: Vacuum Tubes (1940-1956)
The technology behind the primary generation computers was a fragile glass
device, which was called vacuum tubes. These computers were very heavy and
really large in size. These weren’t very reliable and programming on them was a
really tedious task as they used high-level programming language and used no OS.
First-generation computers were used for calculation, storage, and control purpose.
They were too bulky and large that they needed a full room and consume rot of
electricity.
Mai
rst generation computers are:
ENIAC: Electronic Numerical Integrator and Computer, built by J. Presper Eckert
and John V. Mauchly was a general-purpose computer. It had been very heavy,
large, and contained 18,000 vacuum tubes.
EDVAC: Electronic Discrete Variable Automatic Computer was designed by von
Neumann. It could store data also as instruction and thus the speed was
enhanced.
UNIVAC: Universal Automatic Computer was developed in 1952 by Eckert and
Mauchly.
Main characteristics of first generation computers are:
Main electronic component Vacuum tube.
Programming language Machine language.
Main memory Magnetic tapes and magnetic drums.
Input/output devices Paper tape and punched cards.
Speed and size Very slow and very large in size (often taking up entire room).
Examples of the first generation IBM 650, IBM 701, ENIAC, UNIVAC1, etc.
Second Generation Computers: Transistors (1956-1963)
Second-generation computers used the technology of transistors rather than bulky
vacuum tubes. Another feature was the core storage. A transistor may be a device
composed of semiconductor material that amplifies a sign or opens or closes a
circuit.
Transistors were invented in Bell Labs. The use of transistors made it possible to
perform powerfully and with due speed. It reduced the dimensions and price and
thankfully the warmth too, which was generated by vacuum tubes. Central
Processing Unit (CPU), memory, programming language and input, and output
units also came into the force within the second generation.
Programming language was shifted from high level to programming language and
made programming comparatively a simple task for programmers. Languages used
for programming during this era were FORTRAN (1956), ALGOL (1958), and
COBOL (1959).
Main characteristics of second generation computers are:-
Main electronic
Transistor.
component
Programming language Machine language and assembly language.
Memory Magnetic core and magnetic tape/disk.
Input/output devices Magnetic tape and punched cards.
Smaller in size, low power consumption, and generated less heat (in
Power and size
comparison with the first generation computers).
Examples of second
PDP-8, IBM1400 series, IBM 7090 and 7094, UNIVAC 1107, CDC 3600 etc.
generation
Third Generation Computers: Integrated Circuits. (1964-1971)
During the third generation, technology envisaged a shift from huge transistors to
integrated circuits, also referred to as IC. Here a variety of transistors were placed
on silicon chips, called semiconductors. The most feature of this era’s computer
was the speed and reliability. IC was made from silicon and also called silicon
chips.
A single IC, has many transistors, registers, and capacitors built on one thin slice of
silicon. The value size was reduced and memory space and dealing efficiency were
increased during this generation. Programming was now wiped out Higher level
languages like BASIC (Beginners All-purpose Symbolic Instruction Code).
Minicomputers find their shape during this era.
Main characteristics of third generation computers are:
Main electronic component Integrated circuits (ICs)
Programming language High-level language
Memory Large magnetic core, magnetic tape/disk
Input / output devices Magnetic tape, monitor, keyboard, printer, etc.
Examples of third generation IBM 360, IBM 370, PDP-11, NCR 395, B6500, UNIVAC 1108, etc.
Fourth Generation Computers: Micro-processors (1971-Present)
In 1971 First microprocessors were used, the large scale of integration LSI circuits
built on one chip called microprocessors. The most advantage of this technology is
that one microprocessor can contain all the circuits required to perform arithmetic,
logic, and control functions on one chip.
The computers using microchips were called microcomputers. This generation
provided the even smaller size of computers, with larger capacities. That’s not
enough, then Very Large Scale Integrated (VLSI) circuits replaced LSI circuits.
The Intel 4004chip, developed in 1971, located all the components of the pc from
the central processing unit and memory to input/ output controls on one chip and
allowed the dimensions to reduce drastically.
Technologies like multiprocessing, multiprogramming, time-sharing, operating
speed, and virtual memory made it a more user-friendly and customary device. The
concept of private computers and computer networks came into being within the
fourth generation.
Main characteristics of fourth generation computers are:
Main electronic Very large-scale integration (VLSI) and the microprocessor (VLSI has
component thousands of transistors on a single microchip).
Memory semiconductor memory (such as RAM, ROM, etc.)
Input/output devices pointing devices, optical scanning, keyboard, monitor, printer, etc.
Examples of fourth
IBM PC, STAR 1000, APPLE II, Apple Macintosh, Alter 8800, etc.
generation
Fifth Generation Computers
The technology behind the fifth generation of computers is AI. It allows computers
to behave like humans. It is often seen in programs like voice recognition, area of
medicines, and entertainment. Within the field of games playing also it’s shown
remarkable performance where computers are capable of beating human
competitors.
The speed is highest, size is that the smallest and area of use has remarkably
increased within the fifth generation computers. Though not a hundred percent AI
has been achieved to date but keeping in sight the present developments, it is often
said that this dream also will become a reality very soon.
In order to summarize the features of varied generations of computers, it is often
said that a big improvement has been seen as far because the speed and accuracy of
functioning care, but if we mention the dimensions, it’s being small over the years.
The value is additionally diminishing and reliability is in fact increasing.
Main characteristics of fifth generation computers are:
Based on artificial intelligence, uses the Ultra Large-Scale Integration (ULSI)
Main electronic technology and parallel processing method (ULSI has millions of transistors on a
component single microchip and Parallel processing method use two or more
microprocessors to run tasks simultaneously).
Language Understand natural language (human language).
Size Portable and small in size.
Input / output Trackpad (or touchpad), touchscreen, pen, speech input (recognize
device voice/speech), light scanner, printer, keyboard, monitor, mouse, etc.
Example of fifth
Desktops, laptops, tablets, smartphones, etc.
generation
The concept of hardware and software is explained in detail below −
Hardware
The term hardware refers to mechanical device that makes up computer. Computer
hardware consists of interconnected electronic devices that we can use to control
computer’s operation, input and output. Examples of hardware are CPU, keyboard,
mouse, hard disk, etc.
Hardware Components
Computer hardware is a collection of several components working together. Some
parts are essential and others are added advantages. Computer hardware is made
up of CPU and peripherals as shown in image below.
Software
A set of instructions that drives computer to do stipulated tasks is called a program.
Software instructions are programmed in a computer language, translated into
machine language, and executed by computer. Software can be categorized into two
types −
System software
Application software
System Software
System software operates directly on hardware devices of computer. It provides a
platform to run an application. It provides and supports user functionality. Examples
of system software include operating systems such as Windows, Linux, Unix, etc.
Application Software
An application software is designed for benefit of users to perform one or more
tasks. Examples of application software include Microsoft Word, Excel, PowerPoint,
Oracle, etc.
Differences between Software and Hardware are sorted out below −
Sr. Softwar Hardware
No. e
1 It is a It includes physical
collectio components of computer
n of system.
program
s to
bring
compute
r
hardwar
e
system
into
operatio
n.
2 It It consists of electronic
includes components like ICs,
number diodes, registers, crystals,
s, boards, insulators, etc.
alphabet
s,
alphanu
meric
symbols
,
identifier
s,
keyword
s, etc.
3 Softwar Hardware design is based
e on architectural decisions
products to make it work over a
evolve range of environmental
by conditions and time.
adding
new
features
to
existing
program
s to
support
hardwar
e.
4 It will It is mostly constructed for
vary as all types of computer
per systems.
compute
r and its
built-in
function
s and
program
ming
languag
e.
5 It is The hardware can
designe understand only low-level
d and language or machine
develop language.
ed by
experien
ced
program
mers in
high-
level
languag
e.
6 It is The hardware works only
represe on binary codes 1’s and
nted in 0’s.
any
high-
level
languag
e such
as
BASIC,
COBOL,
C, C++,
JAVA,
etc.
7 The The hardware consists of
software input devices, output
is devices, memory, etc.
categori
zed as
operatin
g
system,
utilities,
languag
e
process
or,
applicati
on
software
, etc.
