SCIENCE AND
TECHNOLOGY
Religion
From the beginning of time, religion has been considered as
the panacea for all ills, and mankind, despite moment of doubt, has always
leaned on religious faith for solace.
Religion has been defined as a system of faith and worship in
practice within a group of people living in a community. Belief in god or
Supreme Being is the basic premise of all religions and even those who worship
Nature bow down to a super power who make all the marvels of nature possible.
Thousands of believers have pursued with single mindedness, the path of
devotion for future salvation.
By religious behavior human seeks to adopt to cope with, or
understand dimensions of life beyond
their explanations or control. These manifestations differed according to place
and time. The simple folk never really doubted the existence of god.
Unfortunately although a number of people believe in him
vaguely, each set of believers had its own version of God. They had their own
theories of what he looked like and what he said to them. The most effective
way to identify religious faith in society had always been through the
ritualistic expressions. When divisions began to appear in these ritualistic
expressions, conflict between various practitioners of faith resulted.
Religion has played a phenomenal role in shaping our history
from the ancient to the modern times. When the age of reasoning succeeded the
age of faith, God was temporarily buried and people wondered if human reason
was so powerful did men need God?
Critical thinkers in 19th and 20th centuries began to say that religion is the opium of the
people. According to Karl marks, religion suppressed social change. Darwin’s
theory blew up basic religious tenets. Karl Marks saw close links between the
ruling class and the heads of religions and was eager to blow up both. God was
dead, announced Nietzsche.
Traditional function of religion seems to have been one of
providing a system of meaningful interaction by defining taboos or reinforcing
rules without which society could disintegrate. Young people today are
perplexed looking for a fresh concept of faith which will give them freedom,
side by side with stability.
E. M. Forster asserts that tolerance, good temper, and
sympathy- they are what matter really, and if the human race is not to
collapse, they must come to the front before long. The function of our
universities is to produce in the students the quality of compassion for the
suffering humanity and the quality which enables the individuals to treat one
another in a truly democratic spirit.
Economic growth
Scientific discoveries and the consequential technological
changes have completely revolutionized the life style and living standards of
people.
Since the advent of industrial revolution, different periods
have been marked by advances in different clusters of inventions. The first
wave of invention that lasted for 60 years beginning 1785 was marked by
progress in water, power, textiles and iron. The second wave lasted for 55
years between 1845 and 1900 and this was propelled by inventions in rail and
steel. The third wave beginning 1900 and going up to the end of the first half
of the century was marked by inventions in electricity, chemicals and internal
combustion engine. The fourth wave was powered by oil, electronics, aviation
and mass production. India is in the midst of fifth wave dominated by
semiconductors, fiber optics, genetics and software.
Strides in the 20th century
The century opened on a bright note—with the electric powered
lamp. Science then advanced at supersonic speed.
The automobile rolled out, the airplane took off, and man in
a great leap conquered space. Information technology made possible a global
village and artificial intelligence opened new windows to cyberspace. Man
played God to create and to destroy. He split the atom to destroy his brothers
and cloned beings to create a brave new world.
Information Technology
Information technology (IT), which comprises electronic
computer technology and telecommunication technology, has in a few decades
changed our society. Behind this development lies an advanced scientific and
technical development originating from fundamental scientific inventions.
Information technology has been in the process of bringing
about openness, networking, democratic functioning and social transformation.
Technology is changing societies across the globe in terms of work, education
thought process and overall work and life style. It brings transparency,
responsibility, accountability and better social justice.
The rapid development of electronic computer technology
started with the invention of the integrated circuit (IC) around 1960 and the
microprocessor in 1970s; when the number of components on a chip became
sufficiently large to allow the creation of a complete microcomputer.
Chip development has been marked to be equally dynamic and
powerful development in telecommunication technology. Just as the IC has been
and is a prime mover for electronic computer technology, ultra-rapid
transistors and semiconductor lasers based on hetero structures of
semiconductors are playing a decisive part in telecommunication.
The invention of the transistor just before1947 is usually
taken to mark the start of the development of modern semiconductor technology
(Nobel prize in physics 1956 to William B Shockley, John Bardeen and Walter H
Brattain). With the transistor there came a component that was considerably
smaller, more reliable and less energy consuming than the radio valve, which
thus lost its importance.
In the beginning of the 1950s there were ideas and thoughts
about manufacturing transistors resisters and condensers in a composite
semiconductor block, an IC. The IC is more a technical invention than a
discovery. However it is evident that it embraces many physical issues. One
example is the question of how aluminum and gold, which are part of an IC,
differ regarding their adhesion to silicon. Another question is how to produce
dense layers that are only a few atoms thick.
M. J. Kelly director of research of Bell Laboratories had the
fore-sight to recognize that reliable, expanded telephone communication
required electronic, rather than electro-mechanical switching and better
amplifiers. He formed a solid-state research group consisting of theoretical
and experimental physicists.
The Transistor was born on 16-12-1947.
In 1951, three years after the discovery of amplifier in
solid, transistors were produced commercially. Silicon transistor was produced
in 1954 by Texas. By 1961, Texas and others commercially produced ICs in USA.
- discrete transistors
- small scale integration <100 components
- medium scale integration 100 to 1000 components
- large scale integration 1000 to 10000 components
- very large scale integration >10000 components
Junction field effect transistor (JFET) was produced by
Terzner in France in 1958.Metal oxide semiconductor field effect transistor
(MOSFET) by Bell laboratories in 1960. Operation amplifier (a709) ICs were
produced in 1964.
ICs have made the marriage of communication and computation
possible-the digital signal processing.
The first microprocessor the Intel 4004 was launched in 1971.
It contained 2300 transistors and ran at 0.1 MHz. in the early eighties, at the
dawn of the PC era, the clock speed of a PC’s processor was 5 MHz. Fifty years
on, we are surrounded by millions of transistors – in radios, television,
telephone and computers.
THE PERSIONAL
COMPUTER (PC)
California—the first Silicon Valley in USA; started in
1970-the experimental PC. The 1975 saw an Altair 8800 PC. But fully developed
PC of Intel hardware and Microsoft software- emerged in 1981 only. Within two
decades from 1981 to 2001, one billion PCs were sold all over the world.
INTERNET BACKGROUND
Advanced Research Project Agency (ARPA) was launched in USA
around 1969 to set up a pocket switched network consisting of a subnet and host
computers. By 1974 ARPA invented a model
of protocols known as TCP/IP for data communication over internetwoks. The
TCP/IP model and protocols were specifically designed to handle communication
over internetworks. By 1983 ARPANET was stable and successful. By 1984 NSF
decided to build a backbone network. By 1990 internet was born in USA 3000
networks and 200,000 computers. In 1992
internet society was formed. By 1995 there was exponential growth of internet
services throughout the world.
TCP/IP reference model and TCP/IP protocol stack makes
universal service possible and can be compared to telephone system.
INTERNET
Internet is a network of connections through which
information from one point can be transmitted to another; in a way it is quite
similar to the network of roads which facilitate movement of vehicles from one
place to another. In road transport, a highway is a rather wide road
unencumbered by obstacles so that a vehicle can move on them at very high
speeds. Information super highways are similar connections that permit
communication of digital information at very high speeds.
The rules of communication are often referred to as
protocols. When a message is sent through internet, it is not transmitted
through a dedicated line, as is the case with telephone. Instead the message is
broken up into pieces (pockets) using a transmission protocol and the internet
protocol assigned to each pocket, its distinctive identification, which
includes the address of the sender as well as the receiver. The message is then
re-assembled at the received end.
The transmission control protocol (TCP) breaks up the
information sent on the internet, each containing 1-150 bytes. It numbers each
of the units, puts each into a pocket and thus helps to send it over the
network. Internet protocol (IP) governs the way these pockets are addressed and
routed along the internet. Thus the various pockets that comprise a message may
travel a different route and take a different time to arrive at its
destination. Some may even get damaged on the way. At the recipient’s end TCP
extracts the data from each pocket, checks for its accuracy, and reassembles
them into their original order. If it finds that any data are lost or damaged,
it requests the sender computer to transmit them again. Thus these protocols
(TCP/IP) really make communication through the internet possible.
A machine (PC) is on the internet if it runs the TCP/IP
protocol stack, has an IP address, and has the ability to send IP pockets to
all the other machines on the internet. Internet had four main applications: E
mail, news, remote login and file transfer.
Internet as a
global information system
Transmission control protocol (TCP) and the internet protocol
(IP) – these protocols are usually lumped together as TCP/IP and are embedded
in the software for operating systems.
Servers
Servers are computers dedicated to the purpose of providing
information to the internet. They run specialized software for each type of
internet application. These include e-mail, discussion groups, long distance
computing and file transfers.
Routers
Routers are computers that form part of the communication net
and that route or direct the data along the best available paths into the
networks.
The network architecture is referred to as TCP/IP. The data
are transmitted in pockets. Many separate functions are to e performed in
pocket transmission; such as pocket addressing, routing, and coping with pocket
congestion.
Internet protocol (IP)
In this layer, the pockets of information are passed along
the internet from router to router and to the host stations. No exact path is
laid out before hand and the IP layers in the routers must provide the
destination address for the next leg of the journey so to speak. This
destination address is part of the IP header attached to the pocket. The source
address is also included as part of the IP header. The problems of lost pockets
or pockets arriving out of sequence are not a concern of the IP layer.
Transmission control protocol (TCP)
With TCP, information is passed back and forth between
transport layers, which control the information flow. This includes such
information as the correct sequencing of the pockets, replacement of lost
pockets and adjusting the transmission rate of pockets to prevent congestion.
The TCP layer is termed connection oriented, because sender and receiver must
be in communication with each other to implement the protocol.
All TCP connections are full duplex and point to point. Every
byte on a TCP connection has its own 32-bit sequence number. Sending and
receiving TCP entities exchange data in the form of segments. The TCP protocol
has to address the following:
- the TCP segment header
- TCP connection management
- TCP transmission policy
- TCP congestion control
- TCP time management.
TCP link
A virtual communication link exists between corresponding
layers in the network. The send and receive layers have buffer memories. The
receive buffer holds incoming data while they are being processed. The send
buffer holds data until they are ready for transmission. It also holds copies
of data already sent until it receives an acknowledgement that the original has
been received correctly.
The receive window is the amount of receive buffer space
available at any given time. This changes as the received data are processed
and removed from the buffer. The receive layer sends an acknowledgement signal
to the send TCP layer when it has cleared data from its buffer, and the
acknowledgement also provides an update on the current size of the received window, and so on.
IP Address
Every host and router on the internet has as IP address,
which encodes its network number and host number. The combination is unique: no
two machines have the same IP address. All IP addresses are 32 bit long and are
used in the source address and destination address fields of IP pockets. The 32
bit numbers are usually written in dotted decimal notation. Example, the
hexadecimal address C0290614 is written as 192.41.6.20. The lowest IP address
is 0.0.0.0 and the highest is 255.255.255.255.
Subnet
Subnet means the set of all routers and communication lines
in a network. Each router has a table listing some number of network IP
addresses and some number of host IP addresses. The first kind tells how to get
to distant networks. The second kind tells how to get to local hosts. When an
IP pocket arrives, its destination address is looked up in the routing table.
If the pocket is for a distant network, it is forwarded to the next router on
the interface given in the table. If it is a local host, it is sent directly to
the destination. If the network is not present, the pocket is forwarded to a
default router with more extensive tables. Subnet reduces router table space by
creating a three level hierarchy.
Necessity of Modem
Attenuation and propagation speed are frequency dependent.
Square waves in digital data have a wide spectrum and thus are subject to
strong attenuation and delay distortion. These effects make base band (DC)
signaling unsuitable except at slow speed and over short distances. To get
around the problems associated with DC signaling, especially on telephone
lines, AC signaling is used. A continuous tone in the 1000 to 2000 Hz range is
introduced. Its amplitude, frequency, or phase can be modulated to transmit
information.
Internet services
Telephone companies and others have begun to offer networking
services to any organization that wishes to subscribe. The subnet is owned by
the network operator, providing communication service for the customers’
terminals.
