Реферат по предмету "Иностранный язык"


Where Did The Internet Come From Essay

, Research Paper

Where Did The Internet Come From?

In the summer of 1969, not everyone was at Woodstock. In laboratories on either side of the continent a small group

of computer scientists were quietly changing the future of communication. Their goal was to build a computer

network that would enable researchers around the country to share ideas (Kantrowitz 56).

The Internet we make so much today — the global Internet which has helped scholars so much, where free speech is

flourishing as never before in history — the Internet was a cold war military project. It was designed for purposes of

military communication in a United States devastated by a Soviet nuclear strike. Originally, the Internet was a

post-apocalypse command grid (Tappendorf 1). The threat of nuclear war was a tangible, and frightening, possibility

during the cold war period. In the 1960s the Vietnam War was grabbing all of the headlines. The history books

describe the decade as brimming with social unrest and change. This decade also witnessed the birth of a military

experiment that was to evolve into what we now call the Net (Net 1).

The history of the Internet begins with the research and development, RAND, group in 1966. Paul Baran was

commissioned by the United States Air Force to do a study on how it could maintain its command control over its

missiles and bombers, after a nuclear attack. Baran’s finished document described several ways to accomplish this

task. What he finally proposes is a packet switched network (Tappendorf 2). Packet switching is a method of

fragmenting messages into sub-parts called packets, routing them to their destinations and reassembling them.

Packetizing information has several advantages. It facilitates allowing several users to share the same connection by

breaking up the data into discrete units which can be routed separately. Because no transmission medium is 100%

reliable, packet switching allows one bad packet to be re-sent while other good packets are uninterrupted in their

transmission (Hardy 6).

Packets may carry information about themselves, where they have been and where they are going. In addition,

packets may be compressed for speed and size advantages or encrypted for security. Most packets carry some sort

of internal check for consistency that helps to weed out bad packets. Packetizing data has advantages in overcoming

certain inherent bandwidth and speed constraints, particularly in older network and modem based communication

(Hardy 6).

The early pioneers of Advanced Research Projects Agency network, ARPAnet, wanted to create a network that was

robust, reliable, and did not have a single point of failure. A single point of failure would be a network designed with

one device that was the master node, or controlling device, for the network. This leads to problems in that when the

master node goes down, the whole entire network is lost. These early pioneers of ARPAnet acknowledged this

single point of failure concept, in turn, created a network that had no central controlling device; rather, it was made

up of individual devices, or nodes that all worked together and participated on the network. Although these first

networks consisted of few machines, it laid the foundation for things to come (Boyce 492).

The reliable networking part involved dynamic rerouting. If one of the network links were to become disrupted by

enemy attack, the traffic on it could automatically be rerouted to other links. Fortunately, the net rarely has come

under enemy attack. But an errant backhoe cutting a cable is just as much of a threat, so it’s important for the net to

be backhoe resistant (Levine 12).

Starting with the ARPAnet the government began researching ways to exchange information among various

government sites located in the United States. The research and implementation of ARPAnet led to the early

beginnings of the Internet. This network allowed government officials at various sites to exchange files, documents,

and messages with one another, even though they were physically separated by many miles (Boyce 492).

In 1969, what would later become the Internet was founded. It contrasts sharply with today’s Internet. The ARPAnet

network had four machines on it, linked together with a packet switched network. Soon afterward other government

agencies became interested in this new network; Department of Defense, NASA, National Science Foundation, and

the Federal Reserve Board. Because of this new interest and the fact that ARPAnet was growing, now 24 nodes in

1972, Information Processing Techniques Office, IPTO, began to look to other ways to transmit data other than

through a wire. Two projects were launched to settle these needs. The first was the use of satellites for data

transmission. IPTO quickly learned that it would be possible to send data via satellite and went into negotiations

with the board of directors of International Telecommunications Satellite Organization. The second project was for

radio transmitted data. It soon also became apparent that a packet switched radio network for mobile computing

would be possible. In 1976, the packet satellite project went into practical use. Atlantic packet Satellite network,

SATNET, was born. This network linked the United States with Europe. This network was interesting in that it used

commercial Intelsat satellites that were owned by the International Telecommunications Satellite Organization as

opposed to government military satellites (Tappendorf 2).

In the same year a man called Ray Tomlinson created an e-mail program that could send personal messages across

the network. Seems harmless enough, but this development played an important role in the nets evolution by helping

it move further away from its military roots. The academics with access to the system were using it predominantly to

communicate with colleagues, and their messages were not always about research. Mailing lists on a variety of

subjects proved to be very popular (Net 2).

In 1973, the United States Defense Advanced Research Projects Agency, DARPA, initiated a research program to

investigate techniques and technologies for interlining packet networks of various kinds. The objective was to

develop communication protocols which would allow networked computers to communicate transparently across

multiple, linked packet networks. This was called the Internetting Project and the system of networks which emerged

from the research was known as the Internet. The system of protocols which was developed over the course of this

research effort became known as the TCP/IP protocol suite, after the two initial protocols developed: Transmission

Control Protocol, TCP, and Internet Protocol, IP (Liener 1). In 1976 the Department of Defense, began to experiment

with this new protocol and soon decided to require it for use on ARPAnet. January 1983 was the date fixed as when

every machine connected to ARPAnet had to use this new protocol (Tappendorf 3). In addition to the selection of

TCP/IP for the NSFNET program, Federal agencies made and implemented several other policy decisions which

shaped the Internet of today (Leiner 11). The creation of the TCP/IP protocol made possible the text based Net

communications systems so popular today, including electronic mail, discussion lists, file indexing, and hypertext.

E-mail, of course, is the most widely used of the Net services, the most convenient and the most functional (Diamond

42).

The backbone had made the transition from a network built from routers out of the research community to

commercial equipment. In its 8 1/2 year lifetime, the backbone had grown from six nodes with 56 kbps links to 21

nodes with multiple 45 Mbps links. It had seen the Internet grow over 50,000 networks on all seven continents and

outer space, with approximately 29,000 networks in the United States (Leiner 12).

Widespread development of Lans, Pcs, and workstations in the 1980s allowed the nascent Internet to flourish.

Ethernet technology, developed by Bob Metcalfe at Xerox PARC in 1973, is now probably the dominant network

technology in the Internet, and Pcs and workstations the dominate computers. This change from having a few

networks with a modest number of time-shared hosts, the original ARPAnet model, to having many networks has

resulted in a number of new concepts and changes to the underlying technology. First, it resulted in the definition of

three network classes A, B, and C to accommodate the range of networks. Class A represented large national scale

networks, a small number of networks with large number of hosts; Class B represented regional scale networks; and

Class C represented local area networks, a large number of networks with relatively few hosts (Leiner 8).

Beginning around 1980, university computing was moving from a small number of large time-sharing machines, each

of which served hundreds of simultaneous users, to a large number of smaller desktop workstations for individual

users. Because users had gotten used to the advantages of time-sharing systems, such as shared directories of files

and e-mail, they wanted to keep those same facilities on their workstations (Levine 12). Workstation manufactures

began to include the necessary network hardware also, so all anyone had to do to get a working network was to

string a cable to connect the workstations, something that universities could do inexpensively because they usually

could get students to do it (Levine 13).

In 1983, the ARPAnet was split into ARPAnet and MILnet. The latter was integrated into the Defense Data Network

created in 1982. ARPAnet was taken out of service in 1990. ARPAnet’s role as network backbone was taken over by

NSFNET which may in time be supplanted by the National Research and Educational Network, NREN (Hardy 8).

In 1988, in a conscious effort to test Federal policy on commercial use of Internet, the corporation for National

research Initiatives approached the Federal Networking Council for permission to experiment with the

interconnection of MCI Mail with the Internet. An experimental electronic mail relay was built and put into operation

in 1989, and shortly thereafter Compuserve, ATTMail, and Sprintmail, followed suit. Once again, a far-sighted

experimental effort coupled with wise policy choice stimulated investment by industry and expansion of the nation’s

infrastructure. In the past few years, commercial use of the Internet has exploded (Cerf 5).

The Internet is experiencing exponential growth in the number of networks, number of hosts, and volume of traffic.

NSFNET backbone traffic more than doubled annually from a terabyte per month in March 1991 to 18 terabytes, a

terabyte is a thousand bytes, a month in November 1994. The number of host computers increased from 200 to

5,000,000 in the 12 years between 1983-1995 — a factor of 25,000 (Cerf 5).

In an extraordinary development, the NSFNET backbone was retired at the end of April 1995, with almost no visible

efforts from the point of view of users. This left all of the hard work to be handled by the Internet service providers.

A fully commercial system of backbones has been erected where a government sponsored system once existed.

Indeed, the key networks that made the Internet possible are now gone — but the Internet thrives (Cerf 6).

In 1990, Hyper Text Markup Language, HTML, a hypertext Internet protocol which would communicate the graphic

info on the Internet, was introduced. Each individual could create graphic pages, a website, which then became part

of a huge, virtual hypertext network called the World Wide Web. The enhanced Internet was informally renamed the

Web and a huge additional audience was created (Wendell 1).

The initial development of the Web was limited to text; it did not have the multimedia capabilities of today’s

browsers. Despite this, Tim Lee’s project was the basis for later developments. In 1992, his software was released to

the public. Its popularity grew steadily, but by February 1993, the Web still only accounted for 0.1 per cent of all

Internet traffic. When we first connected to the Internet through a university account it was a bland textual world. At

this point in time it had not become the major attraction that it is today (Net 3).

One of the major forces behind the exponential growth of the Internet is a variety of new capabilities in the network –

particularly directory, indexing, and searching services that help users discover information in the vast sea of the

Internet. Many of these services have started as university research efforts and evolved into businesses. Examples

include the Wide Area Information Service, Archie, LYCOS from Carnegie Mellon, YAHOO from Stanford, and

INFOSEEK. Aiding and stimulating these services is the recent arrival of a killer ap for the Internet: the World Wide

Web (Cerf 6).

The Web is a hypertext system which has the ability to link documents together. Hypertext is not a new idea, in 1945

Vaneavear Bush, the science adviser to president Eisenhower came up with the idea of a machine that would not

only store vast amounts of information, but also allow readers to link related information. In 1968, the eccentric Ted

Nelson coined the term hypertext, and real efforts were finally made to create working models. Ted Nelson went on to

found the overly ambitious Xanadu project, but the first real system accessible to the public was developed by

Apple computers as late as 1987 (Net 2).

The development of Tim Lee’s World Wide Web project becoming the most successful hypertext system was largely

due to software developments that dramatically improved its look and interface. The major breakthrough came in

June 1993, with the release of the Mosaic browser for Windows. It was created by the National Center for

Supercomputing Applications. The initial versions of Mosaic are very similar to the browsers we use today. With

this new development the Web became far more popular. By 1994, the Web accounted for most of the traffic across

the net. In 1995, Netscape Communications Corp. was founded by Mark Andreessen and others involved in the

original Mosaic project. The new Netscape browser ushered in a new era for the Internet. The fact that Microsoft is

now trying to get a piece of this market is testimony to the part that Mosaic and Netscape have played in the Web’s

commercial and popular appeal (Net 2).

The development of HTML and the Mosaic browser led to the explosion of Internet usage of the World Wide Web

in particular. But the World Wide Web is not the only aspect of the Internet that has grown since 1983. E-mail still

remains the most used application on the Internet. Other usage of the Internet includes: FTP (File Transfer Protocol),

Usenet (Internet newsgroups), Archie, Gopher, Telnet, and IRC (Internet Relay Chat). It is all of these applications

together that have led to the growth of the Internet. Today, there are more than 30 million users who are using the

Internet. This is a 6,000 percent increase over the number of users who were using the Internet in 1983 (Boyce 493).

As of May 1995, there were over 30,000 Web sites on the Internet and the number is doubling every two months.

companies that were formerly unsure about the utility of the Internet have rushed to use the Web as a means of

presenting products and services. The rest of the 1990s belongs to the content providers, who will use the rapidly

evolving infrastructure to bring increasingly sophisticated material to consumers (Cerf 6).

The explosive growth of the Internet has involved millions of individual users with modem-equipped personal

computers. The prime cause of the boom has been development of a far-flung World Wide Web service — a

collection of several hundred thousand independent computers, called Web servers, scattered worldwide. There are

more than 30 million users and two million computers on the Internet. The web has grown to more than 50 million

public pages with millions more private pages behind corporate firewalls (Curtis 9).

In Anthony Curtis’s timeline he states that Bob Metcalfe, inventor of Ethernet, has predicted a meltdown on the

Internet, citing alarming usage figures. Bob Metalfe said that in the first half of 1996, 3.5 million new hosts were

added to the already-congested conglomeration of Internet networks. Netscape alone gets 80 million hits on its Web

site each day. America On-Line, Netcom and small Internet service providers have experienced serious network

crashes and extensive down times for their services. A full 30 percent of telephone calls to service providers get a

busy signal. The rate of growth is a giant tsunami nearing the shores of our accessibility to unlimited information

(Curtis 10).

The Internet has changed much in the two decades since it came into existence. It was conceived in the era of

time-sharing, but has survived into the era of personal computers, client-server, peer-to-peer computer, and the

network computer. It was designed before LANs existed, but has accommodated that new network technology. It

was envisioned as supporting a range of functions from file sharing and remote login to resource sharing and

collaboration, and has spawned electronic mail and ,more recently, the World Wide Web. But most important, it

started as the creation of a small band of dedicated researchers, and has grown to be a commercial success with

billions of dollars of annual investment (Leiner 18).

There is also now talk of Internet2. With the promise of access and transfer rates of up to 1,000 times what is

possible with the Internet today, the Internet2 (I2) project is deserving of the attention it has received. But do not

expect to be cruising at lightning speed anytime soon. Internet2 is currently confined to academia, government

research centers, and non profit organizations (Krueger 302).

It remains to be seen whether Internet2 can accomplish its goals and then merge its findings and advances with the

commercial Internet in the time frame suggested. In the end, improved bandwidth and multimedia solutions that meet

or exceed the goals of the Next Generation Internet, NGI, may be realized — all by the year 2002 deadline. Only time

will tell. If I2 flies, however, we may soon hear the buzzword Internet3 (Krueger 306).

One should not conclude that the Internet has now finished changing. The Internet, although a network in name and

geography, is a creature of the computer, not the traditional network of the telephone or television industry. It will,

indeed it must, continue to change and evolve at the speed of the computer industry if it is to remain relevant. The

most pressing question for the future of the Internet is not how the technology will change, but how the process of

change and evolution itself will be managed. If the Internet stumbles, it will not be because we lack for technology,

vision, or motivation. It will be because we cannot set a direction and march collectively into the future (Leiner 18).

WORKS CITED

A Brief History of the Internet and Related Networks. http://www.isoc.org/internet- history/cerf.html 23 March 1998.

Boyce, Jim. Upgrading Pcs Illustrated. Indianapolis: Que, 1997.

Cerf, Vinton. Computer Networking: Global infrastructure for the 21st Century.

http://www.cs.washington.edu/homes/lazowska/cra/networks.html 3 April 1998.

Curtis, Anthony. Timeline. http://www.tui.edu/Help/History.html 13 April 1998.

Dimond, Edwin and Stephen Bates. “The Ancient History of the Internet.” American Heritage. Oct. 1995: 34-45.

Hardy, Henery. The History of the Net. http://www.ocean.ic.net/ftp/doc/nethist.html

3 April 1998.

Kantrowiz, Barbara, and Adam Rogers. “The Birth of the Internet.” Newsweek 8 Aug. 1994: 56-7.

Krueger, Don. “Internet2 A Learning Experience.” Computer Shopper. May 1998:

302-306.

Levine, John, and Carol Baroudi. The Internet for Dummies 2nd Edition. San Mateo: IDG Books, 1994.

Liener, Barry. A Brief History of the Internet. http://www.isoc.org/internet- history/brief.html 23 March 1998.

Net Hype. http://dove.mtx.net.au/~jrowse/net/hypebeg.html 23 March 1998.

Tappendorf, Sean. ARPANET and Beyond. http://clavin.uinc.edu/sean/ internet_history.html

Wendell, Kyla. Internet History. http:/tdi.uregina.ca/~ursc/internet/history.html

23 March 1998.




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