專業(yè)英語計算機(jī)全部文件5版

PART

2INTERNET

APPLICATIONSCHAPTER

4

TRADITIONAL

INTERNET

APPLICATIONSCHAPTER

4

TRADITIONAL

INTERNET

APPLICATIONS4.1.1

ABOUT

WWWKEYWORDSWWW

(Word

Wide

Web)HyperTextclientbrowsersearchaccessdownload萬維網(wǎng)，環(huán)球信息網(wǎng)超文本客戶

瀏覽器搜索

訪問

下載KEYWORDSserverprotocol服務(wù)器協(xié)議HTTP

(Hyper-Text

Transfer

Protocol)超文本傳輸協(xié)議web

page

網(wǎng)頁URL

(Uniform

Resource

Locator)統(tǒng)一資源定位符（地址）search

enginesearch

criteria搜索引擎搜索條件KEYWORDSISP

(Internet

Service

Provider)因特網(wǎng)服務(wù)提供商pathAOL(America

On

Line)exploresurfpersonal

Web

siteregisterhost通路，路徑美國在線

探索沖浪個人網(wǎng)站注冊宿主機(jī)，主機(jī)enabling

users to

enter

search

criteria

on a

topic

and

haveseveral

URLs

returned

for

Web

pages

that

pertain

to

thedesiredinformation.

WWW

or

Web

is

a

large

network

of

Internet

serversproviding

hypertext

and

other

services

to

terminals

runningclient

applications

such

as

a

browser.WWW

enables

users

to

search,access,and

downloadinformation

from

a

worldwide

series

of

networked

serverswhere

information

is

dynamically

interlinked.A

Web

clientpasses

a

user’s

request

for

information

to

a

server,usuallyby

way

of

a

Web

browser.The

server

后面an是d同位c語lientcommunicate

through

a

transfer

protocol,usually

theHypeText

Transfer

Protocol

(HTTP).The

server

thenaccesses

a

Web

page

using

a

Uniform

Resource

Locator(URL).Search

engines

are

available

to

simplify

access

by萬維網(wǎng)是一種由多個因特網(wǎng)服務(wù)器組成的大型網(wǎng)絡(luò)，它向運(yùn)行客戶應(yīng)用程序（如瀏覽器軟件）的終端，提供超文本和其他服務(wù)。萬維網(wǎng)允許用戶從動態(tài)鏈接信息的全球聯(lián)網(wǎng)服

務(wù)器系列中搜索、訪問和下載信息。Web客戶通常通過Web瀏覽器，向服務(wù)器傳送用戶需要信息的請求。服務(wù)器與客戶通過傳輸協(xié)議，通常是超文本傳輸協(xié)

議（HTTP）進(jìn)行通信。然后，服務(wù)器用統(tǒng)一資源定位符（URL）訪問網(wǎng)頁。搜索引擎可用來簡化訪問，允許用戶輸入某一題目的搜索條件，從而使若干

URL返回有關(guān)所需信息的網(wǎng)頁。college

or

university

most

likely

provides

you

with

freeaccess

to

the

Internet

either

through

its

local

area

networksor

through

a dial-up

or

telephone connection.

There arealso

some

companies

that

offer

free

Internet

access.The

most

widely

used

commercial

Internet

serviceproviders

are

national

providers

(e.g.

America

Online(AOL))

and

wireless

providers.1.

ProvidersThe

most

common

way

to

access

the

Internet

isthrough

an

Internet

service

provider

(ISP).

The

providers

arealready

connected

to

the

Internet

and

provide

a

path

orconnection

for

individua很ls可能to

access

the

Internet.Your1.

提供商訪問因特網(wǎng)最常用的方法是通過因特網(wǎng)服務(wù)提

供商（ISP）。這些提供商已經(jīng)連入因特網(wǎng)并為個人訪問因特網(wǎng)提供通路或連接。你們的學(xué)院或大學(xué)，

很可能通過局域網(wǎng)或電話撥號連接，免費(fèi)讓你訪問

因特網(wǎng)。有一些公司也提供免費(fèi)的因特網(wǎng)訪問服務(wù)。最廣泛使用的商業(yè)因特網(wǎng)服務(wù)提供商是全國性的提供商（例如美國在線（AOL））和無線提供商。explore,

or

to

surf

the

Web

by

easily

moving

from

oneWeb

site

to

another.

[5]

Three

well-known

browsers

areMozilla

Firefox,

Netscape

Communications,

andMicrosoft

Internet

Explorer.

(See

Figure

4-1.)2.

BrowsersBrowsers

are

programs

that

provide

access

to

Webresources.

This

software

connects

you

to

remotecomputers,

opens

and

transfers

files,

displays

text

andimages,

and

provides

in

one

tool

an

plicated

interface

tothe

Internet

and

Web

documents.Browsers

allow

y探o索u

to2.

瀏覽器瀏覽器是訪問萬維網(wǎng)資源的程序。這種軟件把你連向遠(yuǎn)端計算機(jī)、打開并傳輸文件、顯示文本和圖像，并在一種工具中提供訪問因特網(wǎng)和萬維網(wǎng)文檔的簡單界面。瀏覽器能使你很容易地從一個網(wǎng)站移動到另一個網(wǎng)站，對萬維網(wǎng)進(jìn)行探索或沖浪。三個著名的瀏覽器是Mozilla

Firefox、Netscape

Communications和微軟公司的因特網(wǎng)瀏覽器（見圖4-

1）。Figure

4-1 Internet

ExplorerBrowser

is

a

GUI-based

hypertext

client

application,used

to

access

hypertext

documents

and

other

serviceslocated

on

innumerable

remote

servers

throughout

theAs

you

see

from

Figure 4-2,

what

goes

on

when

youheavily

on

the

HTML

language.W方W式W狀語a從nd句Internet.主語從句分c詞lic短k語作a

狀h語yperlink

is

a

pretty

significant

series

of

events,

involving

not

only

your

Web

browser

software,but

also

a

Web

server

somewhere,and

the

transactions

involved

rely瀏覽器是一種基于圖形用戶接口的超文本客戶應(yīng)用程序，用于通過萬維網(wǎng)和因特網(wǎng)，對無數(shù)個遠(yuǎn)程服務(wù)器上的超文本文檔和其他服務(wù)進(jìn)行訪問。如圖4-2所示，當(dāng)單擊超鏈接時，所發(fā)生的是一連串十分精彩的事件，不僅包括Web瀏覽器軟件，而且包括某處的Web服務(wù)器，并且所包含的這些事務(wù)緊緊地依賴于HTML語言。3.

Personal

Web

SitesDo

you

have

something

to

share

with

the

world?Would

you

like

a

personal

Web

site,

but

don’t

want

to

dealwith

learning

HTML?

Creating

your

own

home

on

theInternet

is

easy,

and

there

are

many

services

available

to

getyoustarted.

A

service

site

on

the

Web

provides

access

to

tools

tocreate

personal

Web

pages.After

registering

with

the

site,you

create

your

Web

pages

using

the

tools

provided.

Oncecompleted,

the

service

site

acts

as

a

host

for

your

personalWeb

site

and

others

are

free

to

visit

it

from

anywhere

in

theworld.使用3.

個人網(wǎng)站你想和全世界共享某件事情嗎？你是否喜歡個人網(wǎng)站，但又不想學(xué)習(xí)HTML語言？在因特網(wǎng)上創(chuàng)建你自己的主頁很容易，有很多服務(wù)能幫助你開始這項(xiàng)工作。萬維網(wǎng)上的服務(wù)網(wǎng)站提供制作個人網(wǎng)頁的工具。在注冊到該網(wǎng)站之后，你就可以使用所提供的工具

制作你的網(wǎng)頁了。一旦網(wǎng)頁制作完成，該服務(wù)網(wǎng)站

就作為你個人網(wǎng)站的宿主機(jī)使用了，而且其他網(wǎng)站

可以從世界上任何地方免費(fèi)訪問你的個人網(wǎng)站。EXERCISESMultiple

Choices1.

Web

a,c,d

.provides

hypertext

servicesallows

the

user’s

terminals

running

server

programs

tobe

usedallows

the

user’s

terminals

running

client

programs

tobe

usedallows

the

user’s

terminals

running

browser

to

beusedA

Web

client

b,c,d

.passes

a

user’s

request

for

information

to

anotherclientpasses

a

user’s

request

for

information

to

a

serveruses

HTTP

to

transfer

its

requestcan

use

search

enginesEXERCISESMultiple

ChoicesA

Web

server

a,b,d

.accesses

a

Web

page

using

URLcan

communicate

with

client

via

HTTPhas

several

search

engines

to

be

usedcan

send

a

search

result

to

a

client4.

ISP

a,b,c

.is

the

abbreviation

of

Internet

Service

Providercan

provide

a

connection

for

individuals

to

access

theInternethas

always

to

connect

the

Internetusually

offers

you

with

free

access

to

the

Internet.Creating

our

own

Websiteis

difficultis

easierc.

can

use

some

creating

toolsd.

can

ask

some

service

sites

to

give

helpsEXERCISESMultiple

ChoicesBrowsers

a,b,c,d

.are

programs

that

provide

access

to

Web

resourcesprovide

a

simple

interface

to

the

Web

documentsallow

you

to

surf

the

Webconnect

you

to

remote

computersb,c,dEXERCISESMultiple

Choices7.

A

service

site

on

the

Web

a,b,c,d

.offers

some

tools

to

create

personal

Web

pagesshould

ask

you

to

register

to

this

site

before

using

thetools

of

creating

personal

Web

pagescan

act

as

a

host

for

your

personal

Web

siteallows

other

sites

to

visit

the

personal

Web

site

freelyfrom

anywhere

in

the

worldBrowseris

a,c,d

.a

GUI-based

hypertext

client

applicationa

GUI-based

hypertext

server

applicationused

to

access

hypertext

documentsused

to

access

other

services

located

on

innumerableremote

servers

throughout

the

WebEXERCISESMultiple

Choices9.Tocreateapersonal

Website,we

b,c,d

.a.

must

learn

HTML b.

don’t

need

to

learn

HTMLc.

need

some

tools

for

creating

the

Web

site d.

shouldchoice

a

server

site

to

be

a

hostA

Web

browser

wants

to

communicate

with

a

serverviaInternet

a,c

.the

browser

should

send

a

http

requestthe

browser

should

send

a

html

requestthe

server

should

return

a

http

replythe

server

should

return

a

html

replyNOTES[1]terminals是指連入因特網(wǎng)的各種終端。

[2]usually后面是同位語。HTTP(HyperText

TransferProtocol)，超文本傳輸協(xié)議，是互聯(lián)網(wǎng)上應(yīng)用最為廣泛的一種網(wǎng)絡(luò)協(xié)議。所有的WWW文件都必須遵守這個標(biāo)準(zhǔn)。由and

連接的是兩個并列成分，主語為Searchengines；search

criteria是指搜索判據(jù)（關(guān)鍵字）。most

likely

意為“很可能”；either

through…orthrough…方式狀語。dial-uportelephoneconnection是指用modem或ADSL方式連接，有關(guān)這方面的內(nèi)容請參閱3.3節(jié)。explore是探索，surf是沖浪，即在因特網(wǎng)上查看資料的行為。NOTES本段就是一句話。As引導(dǎo)的是方式狀語從句。主句中what引導(dǎo)的是主語從句，involving…現(xiàn)在分詞短語做狀語，其結(jié)構(gòu)為not

only…but

also…。home是指主頁homepage。access

to

此處為“使用”。PART

2INTERNET

APPLICATIONSCHAPTER

4

TRADITIONAL

INTERNET

APPLICATIONSCHAPTER

4

TRADITIONAL

INTERNET

APPLICATIONS4.1.2 SEARCH

ENGINESKEYWORDSsearch

toolspiderindexindex

databasecachequerykey

wordcrawlerfreeware搜索工具網(wǎng)絡(luò)蜘蛛，萬維網(wǎng)查詢工具索引索引數(shù)據(jù)庫高速緩存查詢關(guān)鍵字爬行者，瀏覽器免費(fèi)（自由）軟件，免費(fèi)（自由）件KEYWORDSbuilt-inmajorityminimalisticmergeaddress

bar內(nèi)置的大多數(shù)，大部分

最小的，極小的

合并，融合，融入地址欄1.

Overview定語從句Imagine

walking

into

a

library

where

books

are

piledup

and

strewn

about

without

any

order.Finding賓w語h從a句t

youare

looking

for

would

be

next

to

impossible.As

the

WorldWide

Web

rapidly

grew,it

is

necessary

to

categorizemessage

of

Web

page

and

to

keep

track

of

“what’s

what”and

“what’s

where”.In

the

initial

stages

of

the

Web,it

washard

to

locate

useful

information.In

the

early

days

of

the

World

Wide

Web,

two

graduatestudents

at

Stanford

University,

Jerry

Yang

and

David

Filo,came

up

with

a

way

to

organize

hyperlinks

by

category

andthey

found

it

useful.

In

late

1993

this

way

was

known

as“Jerry

Yang’s

Guide

to

the

WWW.”

The

name

was

soonchanged

to

Yahoo!

and

the

first

search

tool

was

born.1.

概述可以想象，當(dāng)走進(jìn)一個雜亂無章、堆滿了書的圖書館時，要找到所需的資料幾乎是不可能的。隨著WWW的迅速發(fā)展，同樣也需要對網(wǎng)頁信息進(jìn)行分門別類的管理，需要記住“是什么”和“在哪里”。在

Web技術(shù)發(fā)展的初始階段很難查找有用的信息。在WWW的早期，美國斯坦福大學(xué)的兩名研究生

Jerry

Yang和David

Filo提出按照目錄來組織超鏈接的方法，并發(fā)現(xiàn)該方法確實(shí)可行。1993年后期，這種方法被稱為“WWW

Jerry

Yang向?qū)А薄＿@個名字不久被改為Yahoo!，第一個搜索工具就這樣誕生了。Today

there

is

quite

a

collection

of

search

toolsavailable

that

allows

us

to

find

required

information

on

theWeb

quickly

and

easily.

The

collection

of

search

tools

isconstantly

evolving,with

new

ones

coming

onthe

scene

and

others

disappearing.方R式a狀th語e從r

句than

report

on賓h語o從w句each

of

the

popular

search

tools

works,we

will

explain

a

few

of

them

and

suggest

some

Web

presentation定s

語th從a句t

provide

reviews

of

all

of

the

current

search

tools

available.How

search

engines

workA

search

engine

operates,

in

the

following

orderWeb

crawlingIndexingSearching當(dāng)今有許多搜索工具能幫助我們在Web上迅速且方便地找到所需的信息。這些工具不斷地演變，不斷地優(yōu)勝劣汰。與其逐一解釋每個搜索引擎是如何工作的，不如只對其中的少部分進(jìn)行介紹，并且給出一些網(wǎng)頁演示，以回顧現(xiàn)行所有可用的搜索工具。2.

搜索引擎是如何工作的搜索引擎按下列順序操作：①慢慢瀏覽萬維網(wǎng)；②索引；③搜索。Web

search

engines

work

by

storing

informationabout

many

web

pages,

which

they

retrieve

from

the

htmlitself.

These

pages

are

retrieved

by

a

Web

crawler(sometimes

also

known

as

a

spider)

—

an

automated

Webbrowser

which

follows

every

link

on

the

site.

Thecontents

of

each

page

are

then

analyzed

to

determine

how

itshould

be

indexed

(for

example,

words

are

extracted

fromthe

titles,

headings,

or

special

fields

called

meta

tags).

Data

about

web

pages

are

stored

in

an

index

database

foruse

in

later

queries.搜索引擎要存儲很多網(wǎng)頁信息，這些信息都是用html本身檢索的。網(wǎng)頁是用瀏覽器（有時也稱為網(wǎng)絡(luò)蜘蛛）檢索的——一種能自動跟蹤每次網(wǎng)站鏈接的萬維網(wǎng)瀏覽器。然后分析每個網(wǎng)頁的內(nèi)容，以確定如何去索引（例如，從標(biāo)題或稱為元標(biāo)簽的專用字段中提取一些字）。有關(guān)網(wǎng)頁的數(shù)據(jù)，存儲在索引數(shù)據(jù)庫中，便于以后查詢時使用。A

query

can

be

a

single

word.

The

purpose

of

an

index

is

toallow

information

to

be

found

as

quickly

as

possible.

Somesearch

engines,

such

as

Google,

store

all

or

part

of

thesource

page

(referred

to

as

a

cache)

as

well

as

informationabout

the

web

pages,

whereas

others,

such

as

AltaVista,store

every

word

of

every

page

they

find.This

cached

page

always

holds

the

actual

search

tex原t

因si狀n語ce從句it

is

the

one定語th從a句twas

actually

indexed結(jié),果s狀o語i從t

句can

be

very

useful

when

the

content

of

the

current

page

has

been

updated

and

the

search

terms

are

nolonger

init.

查詢可以按單個字進(jìn)行。索引的目的是盡可能快地找到信息。有些搜索引擎，如谷歌，存儲所有或部分源網(wǎng)頁（稱為高速緩存）和有關(guān)該網(wǎng)頁的信息，而其他一些搜索引擎如AltaVista則存儲它們能找到的每頁中的每個字。由于高速緩存的頁是實(shí)際索引的頁，故它保存的總是實(shí)際搜索的文本，因此當(dāng)當(dāng)前網(wǎng)頁的內(nèi)容被更新以后并且搜索的條目不再包含在其中時，這是很有用的。When

a

user

enters

a

query

into

a

search

engine時間狀語(typically

by

using

key

words),the

engine

examines

itsindex

and

provides

a

listing

ofbest-matching

web

pagesaccording

to

its

criteria,usuall狀y語with

a

short

summaryc分o詞nt短a語in做in定g語the

document’s

title

and

sometimes

parts

of

thetext.當(dāng)用戶往搜索引擎中輸入一個查詢時（通常用關(guān)鍵字），該引擎檢查它的索引，并按其自己的標(biāo)準(zhǔn)列出最匹配的網(wǎng)頁，通常還包含文檔標(biāo)題的簡短摘要，有時是部分文本。3.

About

Google

ChromeGoogle

Chrome

is

a

freeware

web

browser

developedby

Google.

It

used

the

WebKit

layout

engine

until

versionand,

with

the

exception

of

its

iOS

releases,

from

versionand

beyond

uses

the

WebKit

fork

Blink

.It

was

first

released

as

a

beta

version

for

MicrosoftWindows

on

September

2,

2008,

and

as

a

stable

publicreleaseonDecember11,2008

As

of

January

2015,

StatCounter

estimates

that

GoogleChrome

has

a

51%

worldwide

usage

share

of

web

browsers,indicating

that

it

is

the

most

widely

used

web

browser

in

theworld3.

有關(guān)Google

ChromeGoogleChrome是谷歌公司開發(fā)的免費(fèi)萬維網(wǎng)瀏覽器，直到第27版，它都使用WebKit布局引擎。隨著iOS各個版本出現(xiàn)異常，從第28版開始及以后的版本，都使用WebKit

fork

Blink引擎。在2008年9月2日，首次為微軟Windows公布了一個beta版，同年12月11日則成為正式公開版本。2015年1月，StatCounter

對Google Chrome進(jìn)行評估，結(jié)果是該瀏覽器在世界范圍內(nèi)的共享率為51%，這表明它是世界上使用最多的瀏覽器。Google

releases

the

majority

of

Chrome’s

source

code

asan

open-source

project

Chromium

A

notable

componentthat

is

not

open

source

is

the

built-in

Adobe

Flash

Player.Google

Chrome

features

a

minimalistic

user

interface,with

its

user-interface

principles

later

being

implementedinto

other

browsers.

For

example,

the

merging

of

theaddress

bar

and

search

bar

into

the

omnibox

.

Chromealso

has

a

reputation

for

strong

browser

performance.作為開源課題Chromium，谷歌公開了Chrome的絕大部分源代碼。而很重要的，內(nèi)置在Adobe

FlashPlayer中的代碼是非開源的。Chrome的特點(diǎn)是極小的用戶界面，而且以后還會植入到其他一些瀏覽器中。例如，將地址欄和搜索欄合并到omnibox

中去。Chrome由于其強(qiáng)勢瀏覽器性能，口碑不錯。EXERCISESTrue/False

F

As

the

WWW

rapidly

grew,

it

is

hard

to

finduseful

information.

F

Google

is

the

first

search

tool

in

the

world.

T

Collection

of

search

tools

is

constantly

evolving,with

new

ones

coming

on

the

scene

and

othersdisappearing.

F

In

order

to

operate

a

search

engine,

we

shouldfollow

five

operations.

F

Search

engines

retrieve

with

http

itself.

T

Web

crawleris

an

automated

Web

browser.

T

Index

database

stores

data

concerning

Web

pages.EXERCISESTrue/False

F

Google

stores

every

word

of

every

page

it

finds.

T

Cached

page

always

holds

the

actu