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browser hypertext packet router bandwidth host

client-server architecture hyperlink downloading packet-switching

UNIT 7

Internet basics

1 In pairs or groups of three ask and answer the following questions. Take it in turns.

a) What is a network protocol?

b) How is client-server architecture different from peer-to-peer (P2P) architecture?

c) How is email sent and received via the Internet? What is the header/trailer of the message? What is a frame?

d) What is a data packet? What happens to it between the starting point and the destination?

e) What do you call an information retrieval system that helps you to find information on the Internet?

f) What do you call a related collection of Internet files, which includes a beginning file called home page?

g) Can you decipher the following abbreviations (initialisms): XML, POP, SMTP, TCP/IP, URL,

LAN, IM? What do they refer to?

Reading

1 Look at the words in the box. First try to explain what they mean, then fill them into the gaps.

The Internet is based on the concept of (1) ________________, where some computers act as servers,

or information providers, while other computers act as clients, or information receivers. The (1)

________________ is not one-to-one, that is, a single client computer may access different servers, and

a single server may be accessed by a number of different client computers.

To access information on the Internet, a user must log on to the client computer’s

(2) ________________ network, usually a local area network (LAN). If the information requested by

the user is on a remote server, the (2) ________________ network connects to other networks. In this

process, the (2) ________________ may need to access a (3) ________________, a device that

determines the best connection path between networks and helps networks to make connections.

Once a connection has been made, the server sends the information to the client in the form of a file.

A special program called (4) ________________ enables the user to view the file. The process of

retrieving files from a remote server to the user’s terminal is called (5) ________________.

The Internet is structured around the concept of (6) ________________ - an interlinked

system of documents in which a user may jump from one document to another in a nonlinear way.

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By clicking on the (7) ________________, which is linked to other related documents, the user is

immediately connected to the respective document.

All data transmitted over the Internet is divided up into small units of information called (8)

________________s, each of which is labelled with a unique number indicating its place in the data

stream. When the various (8) ________________s arrive at their destination, they are re-assembled

using the unique labels. Other features make sure that all the data (8) ________________s arrive intact,

automatically requesting that missing or incomplete (8) ________________ be re-sent from the source.

This system called (9) ________________ uses a series of international standards collectively called

TCP/IP (Transmission Control Protocol/Internet Protocol.) The amount of data a computer network can

transmit is called the (10) _______________ of the network and is usually measured in Kbps or Mbps.

2 Look at the following quotations from some 20 years ago. Are they still valid? Which of them do you consider most striking or typical of cyberspace? Which do you agree/disagree with?

“…The virtual world is objectively present like the physical world, composable like a work of art, and as

unlimited and harmless as a dream. When it becomes widely available, it will not be seen as a medium

within physical reality, but rather as an additional reality.” A

“...When T. Leary gave his blessing to

cyberspace, mainstream America shuddered.

They had seen this before – the typical self-

indulgent, hedonistic, drop-out scene. Virtual

space attracted the attentions of self-styled

‘cyberpunks’ and ‘hackers’ – and suspicions were

confirmed.” C

...If I have no body there,

no one knows I’m

female. There aren’t

many places where no

one notices that. And

there’s a big difference

between hiding my

gender and choosing to

be a man. But is it

possible that I can be

entirely without gender?

If my body is female,

isn’t my mind also

female?” E

“…The worst lie going around? Internet cheerleaders talk

about the technology “community”. Aww, c’mon, there’s no

such thing. You can’t even see the person you are talking with

- how can a community be based upon only written

communication? And for the most part it’s a shouting match.

Would you want to live in a neighbourhood where everyone

yelled at you continually?” D

“…As people worship cathode ray tubes, maybe the disintegration of

community is inevitable. The Internet is advancing that destruction at an

alarming rate.” F

“...Just as the alphabet and the printing

press changed the way people thought,

virtual space will shape our notions of

community, self, shape and time”. B

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3 a) Based on the above statements, which ideas and concepts does the Internet challenge?

b) Tick the quotations whose authors sound worried. What are they worried about?

c) Which aspects of the Internet do you find annoying, frustrating, exciting?

Vocabulary

HOW TO READ A WEBSITE ADDRESS

1 Label the parts of a web site address.

top-level domain extension - ___ domain name - ___ protocol -___ path - ___

URL - ___ query string - ___ subdomain - ___

A B C D E F G

2 Match each keyboard symbol to its name.

1 # a equals/equality sign 10 : j inequality signs, angular (angle) brackets

2 “ b asterisk 11 [ ] k parentheses (round brackets)

3 ( ) c “at” sign 12 < > l dot (full stop)

4 . d semicolon 13 , m hyphen (dash)

5 - e exclamation mark (bang) 14 / n quotation marks (quotes)

6 @ f oblique (forward slash) 15 { } o hash (hashtag)

7 ~ g comma 16 \ p square brackets

8 ; h colon 17 ! q braces

9 * i backslash 18 = r tilde

3 Which of the above symbols are used in web site addresses and email addresses?

4 Fill in the names of the above symbols.

Curly brackets – also called ___________ – are used in mathematics to delimit sets. In many

programming languages, they enclose groups of statements. The _____________ is used in the sense

of “located at”, especially in e-mail addresses. _________________, also called simply brackets (UK),

or _______________ contain material that could be omitted without destroying or altering the meaning

of a sentence. ______________ or inverted commas are used in pairs to set off speech, a phrase or a

word. A _______ function is a mathematical function that converts a large amount of data usually into

a small integer that serves as an index to an array; it may be used to accelerate finding items in a

“…Computers can replace legions of people across every industry. But where does it end? Should we

eliminate teachers? Do you want your kid taught by a software package? I have doubts about the

applicability of computers in many situations, and although they’re always touted as better and cheaper than

people, well, frankly, they’re not. Computers are wonderful. Still, I worry about their impact on our future.”

G

https://www.facebook.com/help/199655413426788/?ref=u2u

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database. A /________________ and a \ _________________ are characters used for specifying the

path – an indicator pointing to the location of a file or folder in a file system. Email addresses are

sometimes wrapped in _________________, which are preceded by display names (Usernames).

Language points

CONDITIONALS III

1 Look at the following example. What happened in reality?

If I had spoken more confidently at the interview, they would have offered me the job.

2 Read the description of the third conditional and complete the rules below.

The third conditional is used to talk about unreal or situations in the past. The “If” clause usually

contains a _______________ tense (simple or continuous) while the main clause contains ________,

could” “might” + past infinitive (“present perfect”)

3 Read the following stories. Then read the sentences below the stories and put the verbs in

brackets into the correct form of the third conditional.

a) A British doctor volunteering in DR Congo used text message instructions from a colleague to

perform a life-saving amputation on a boy. The boy's left arm had been ripped off and was badly

infected. Dr Nott, 52, had never performed the operation but followed instructions from a colleague

who had. He texted his colleague, who texted back step-by-step instructions on how to do it. Mr Nott

had just an elementary operating theatre, but the operation was a success and the teenager made a

full recovery.

b) A tow-truck driver crashed into a car and ended up in a swimming pool. N. Sparks, 25, admitted

he was texting on one mobile phone while he was speaking on the other when his vehicle struck a car

in the upstate Oxford town of Lockport. The tow-truck ended up with its front end in the home's in-

ground pool. The homeowner said it sounded 'like a bomb went off.'

c) A teenage girl trying to walk and text-message at the same time fell into an open sewer manhole,

which was left uncovered and unattended. Alexa L., 15, was walking on Victory Boulevard,

preparing to send a text, when she felt the ground give way. Alexa suffered scrapes on her arms and

back as she slid into the sewer, which had some muck at the bottom.

If there (be) _____________ no mobile phones in the hospital, the operation (not succeed)

_________________. If the driver (not text) _______________ while driving, he (not crash)

___________________ into the pool. If the teenage girl (look) ______________ under her feet, she

(not fall) _______________ into the manhole.

4 Read the following examples.

a) If I had accepted the job, I would be much better off now.

b) If the boss didn’t trust him, he would have sacked him months ago.

Now complete the sentences referring to what happened in reality. Put the verbs in brackets into the

correct form, positive or negative.

I (accept) _______________ the job, so I (be) _______________ much better off.

The boss (trust) _______________ him, so he (sack) _______________ him.

a) and b) are both examples of the mixed conditional. This means that the time in the if-clause is not

the same as the time in the main clause.

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Discussion

NETWORK TOPOLOGIES

1 First, read the introduction and match each type of network topology with the correct illustration.

Topology refers to the physical or logical layout of a network. The topology of a network is a

geometric representation of all devices connecting to each other in the network.

2 Now read the following descriptions and label them.

a) this topology consists of a main run of cable with a terminator at either end; there is a single line

to which all nodes are connected, and the nodes connect only to this line.

b) each node connects directly to a central network hub; data passes through the hub before

continuing to its destination, which manages and controls all the functions of the network.

c) this topology resembles an interconnection of star networks in that individual peripheral nodes are

required to transmit to and receive from any peripheral node to all peripheral nodes including the

original one. This topology allows for the expansion of an existing network, and enables institutions

to configure the network to meet their needs. The function of the central node may be

distributed. As in the conventional star network, individual nodes may thus still be isolated from the

network by a single-point failure of a transmission path to the node.

d) a topology in which every node has exactly two branches connected to it; these nodes and branches

form a circle – if one of the nodes fails, the configuration is broken and cannot work.

e) this topology, similar in structure to d), is more resistant to failures as there are four branches

connected to each node.

f) a network topology in which there is a direct link between any two nodes.

g) a network topology in which there are at least two nodes with two or more paths between them.

star ring bus fully connected tree mesh hybrid dual ring

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h) A combination of any two or more network topologies. Note that sometimes two basic network

topologies, when connected together, can still retain the character of one basic network. Thus, the

_______ network accrues only when two basic networks are connected and the resulting network

topology fails to meet one of the basic topology definitions.

3 Discuss the following questions in groups of three.

Which of the following networks would you recommend for business intelligence; for data

archiving; for central administration offices; for a dynamic company that is likely to scale up; for

start-up companies with limited resources? Here are factors to be considered (apart from costs):

frequency of data exchange – how would heavy traffic affect the performance?

need for frequent reconfiguring and extension (flexibility)

data security /integrity and privacy

time needed for the exchange of information

reliability of data and data retention

need for a hierarchical structure.

4 In groups of three, read the following descriptions (2 topologies each), listing the pros and cons of

each topology, then exchange the information and compare what you have learned with your

observations from the previous exercise. Tick the points you have mentioned.

Mesh topology

Every device is connected with every other device through a point-to-point link, which is a dedicated

one, i.e., it carries traffic only between the two devices. This link ensures that each connection

transports its own load of data. This helps avoid the traffic problems that would crop up if the links

were shared by many devices. The mesh topology is a robust one. Even if a particular link becomes

useless, it will not affect the entire system. Also, it ensures security and privacy. The point-to-point

links help in identifying faults easily and traffic can then be rerouted to avoid suspect links.

However, this topology requires a huge amount of cabling and a number of I/O ports and is difficult

to install and reconfigure. It is rarely used in LANs.

Star topology

Each device is connected to a centrally located hub through a point-to-point link. The star topology

does not permit direct traffic between the devices and there is no direct link between them. The hub

acts as an intermediary between the devices. If a computer wants to send data to another, it first

sends the data to the hub, which in turn transmits the data to other devices. It is most commonly used

in LAN. If any node or cable fails, other nodes are not affected. New nodes can easily be added or

removed.

Bus topology

All the devices are linked through a long cable. Drop lines connect the nodes of the devices to the

cable. When a signal travels along the backbone, some energy gets transformed into heat. Thus, the

signal gets weaker and weaker along the distance it has to travel. The bus topology is easy to install,

but difficult to reconfigure. It uses less cabling than the star, the tree, or the mesh topologies. Adding

new devices is difficult as it requires modifications or replacement of the cable. Any puncture or

break in the bus stops transmission.

Ring topology

Each device is linked to its immediate neighbours on either side of it through a dedicated point-to-

point connection. Signals are passed in one direction until they reach their destination. Each device

has a repeater, which regenerates the bits and passes them whenever a signal is received that is meant

for another device. It is easy to install and reconfigure. A device can be easily added or deleted as it

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requires only two connections. Ring topologies, however, are subject to traffic and media constraints,

i.e., the number of devices and the length of the ring. Another disadvantage is that the traffic is

unidirectional. Any rupture in the ring would disable the whole network. However, this problem can

be solved by using a switch for closing the rupture or a dual ring.

Tree topology

The nodes of some devices are linked to a central hub. The other nodes are indirectly connected to

the hub through a secondary hub, which in turn, is connected to the main hub. The central hub is

active while the secondary hubs are usually passive. The active hub has a hardware device called the

repeater, which regenerates the received bit patterns before sending them out. This strengthens the

transmission and increases the traveling distance of a signal. A passive hub gives a simple

connection to the devices. Tree topologies have advantages similar to those of star topologies;

however, they allow more devices to connect to the central hub. A secondary hub enables more

devices to be connected to the active hub, thus increasing the travelling distance between the devices.

The secondary hub can also isolate or prioritize communications between different computers. Cable

TV network is an example of this.

Hybrid topologies

In hybrid topologies, different topologies can be used in a single network. For example, if one

department in a business organization uses a ring topology, while another uses a bus topology, a

centrally located hub using star topology can be used to connect these two departments.

Language points

REPORTED SPEECH

We use reported speech to report what other people say, think or believe.

A When we are reporting events and ideas in the present, present perfect or future, we do not

change the tense.

Examples:

She says she doesn’t use Facebook.

I have always believed that this is a better model.

They will think that you don’t like their product.

B In reported speech, however, we usually report what was said at a different time, and so we

change the tense to reflect the time that we are reporting.

1 Now complete the table to show the tense shift in the reported speech.

DIRECT SPEECH REPORTED SPEECH

Present Tense Past Tense

Past Tense

Present Perfect

“could”, “would”, “might”

C When we are reporting something said in the past, and we see it from the same viewpoint as the

original speaker and it is still true, it is not necessary to change the tense. The choice is up to the speaker.

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D When we are reporting someone else’s words, we often have to change pronouns and words

referring to the place and/or time.

PLACE SIGNIFIERS TIME SIGNIFIERS

come – go today – that day/then

bring – take tomorrow – the next/following day

this – that yesterday – the day before

these – those next month – the following month

here – there now – then

E Verbs introducing reported speech include those that merely inform, such as reply, answer,

explain, mention, and those that show the attitude/ opinion of the speaker, such as insist, warn,

threaten, promise, complain, claim, demand.

F When reporting questions, the tense changes are the same as when we are reporting statements but

the word order is the one we would use in a statement.

2 Now report the following questions. Make any necessary changes.

Direct question: “When did you last have a security problem?”

Reported question: The operator wanted to know when ___________________________________.

Direct question: “Have you updated your antivirus program?”

Reported question: They asked me if/whether ___________________________________________.

3 During a fictitious interview with V. Bush (1890 – 1974), Jim Marinetti discussed Bush’s early vision

of the “Memex” - a system for indexing, storing, and accessing information, which inspired the

concept of hypertext. Read the interview and complete the exercise below.

J.M.: Dr. Bush, how did you think up such a contraption so long ago?

V.B.: There was a great deal of scientific information after World War II. We had a problem

keeping it all organized. We alphabetized or sorted by number. However, the human mind does not

work that way; it operates by association. I conceived the Memex as a mechanized private library

storing books, records, communications.

J.M.: It sounds very promising - even today. Have you seen modern-day computers? Are they similar

to what you thought the Memex would be?

V. B.: Computers are physically very similar to my Memex but the World Wide Web seems to be a

bit different from it.

J.M.: First, how is it similar?

V. B.: One of the fundamental provisions of the Memex was that any item may select another. The

Web's hyperlinks seem to do this associative indexing work, but it's a bit disorganized because so

many different people can add to the information on the Web.

J. M.: So, are you disappointed with the World Wide Web?

V. B.: Yes and no. I just thought the content of the Memex would be more academic... The Web is

struggling because it’s trying to fulfil many uses. The vision of the Memex was not as interactive as

the Web; you couldn't buy anything using your Memex. Consumer trails can be coded differently

than reference trails and computers can be smart enough to locate the right information.

J.M.: Well, let’s hope that your ideas will help all those information designers out there.

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First, J. Marinetti wanted to know how ___________________________________. V. Bush replied

that there _________________________________ and that they _____________ a problem keeping

it organized. He then added that he ________________ the Memex as a private library storing

books and records. The reporter then asked if V. Bush__________________ modern-day computers

and whether they ______________ similar to his idea of Memex. He also wanted to know if V. Bush

___________________ disappointed with the World Wide Web, to which V. Bush replied that he

_________________ it __________ more academic. He continued, saying that the Web ________

struggling because it ________ trying to fulfil so many uses. In the end, J. Marinetti expressed his

hope that V. Bush’s ideas ___________ help all the information designers to organize information

better.

4 List down similarities and differences between WWW and Memex. Would you approve of the idea

of keeping academic, commercial and user-generated contents separately? Why/Why not?

SIMILARITIES: ___________________________________________________________________

DIFFERENCES: __________________________________________________________________

Revision

1 Answer the following questions.

a) What network protocols are used for the incoming and the outgoing mail, respectively?

b) What are search engines used for?

c) How is the abbreviation for the network protocol separated from the domain name in a web site address?

d) When are the header and the trailer appended to a data packet during email exchange?

e) Which of the topologies is easy to install and requires minimum initial costs; is easiest to

reconfigure; has no direct link between the nodes; has a dedicated link to connect each pair of nodes,

so that a potential rupture has no effect on the other nodes?

2 Put the verbs in brackets into the correct form of the conditional or of the modal verb.

What if there (be) _____________no Google? It's hard to say exactly what the world (look)

__________ like without Google. Perhaps without the mathematical and programming wizardry of

co-founders Larry Page and Sergey Brin, no other company (develop) _______________ a search

engine on par with Google's. And if no one (create) _________ such a search engine, it's hard to say

how profoundly different your Web experiences (be) ____________. First, without Google, the

Internet may not (make)___________ its way so quickly into every aspect of our lives. Without

Google's expertise, you (have) ___________ to remember more things, instead of pulling out your

phone to “google“ the instant answer. Then again, what if Google (turn) ____________ into just

another search engine that joined so many other tools in the Web’s dustbin? Perhaps without a solid

marketing and business plan, another Silicon Valley duo (steal) ___________ Google’s momentum

to create an entirely different phenomenon. And maybe your Internet experiences (be) ________

even better than they are now.

3 Turn the following sentences into the reported speech, using the tense shift where applicable.

Make any other necessary changes.

a) Jane: “My computer has caught a virus”.

Jane complained that _______________________________________________________________

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b) Male colleague: “I am going to replace this faulty drive”.

My colleague said that ______________________________________________________________

c) Expert: “Smartphones and tablets may soon replace desktop computers.”

An expert predicted that _____________________________________________________________

d) Note: “The system will shut down in 10 minutes”.

The note said that __________________________________________________________________

e) Bob: “I was too busy to check this material.”

Bob explained that _________________________________________________________________

f) Mary: “What does www mean?”

Mary wanted to know _______________________________________________________________

g) Tom: “Did you receive my email yesterday?”

Tom asked if ______________________________________________________________________

4 Choose the correct word. Then use the other words from the pairs in sentences of your own.

Both in the star topology and in the tree topology, nodes can be INSULATED/ISOLATED from the

network in the case of malfunction.

In some INSTANTS/INSTANCES, two connected basic network topologies often retain the

character of one basic network and thus cannot qualify as a hybrid network.

The star topology does not permit direct TRANSPORT/TRAFFIC between the devices.

The mesh topology is so robust that even if a particular link becomes useless, it will not

AFFECT/EFFECT the entire system.

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