Internet and world wide web
Internet
The origins of the Internet date back to research commissioned by the United States federal government in the 1960s to build robust, fault-tolerant communication via computer networks. The primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and military networks in the 1980s. The funding of the National Science Foundation Networkas a new backbone in the 1980s, as well as private funding for other commercial extensions, led to worldwide participation in the development of new networking technologies, and the merger of many networks. The linking of commercial networks and enterprises by the early 1990s marks the beginning of the transition to the modern Internet, and generated a sustained exponential growth as generations of institutional, personal, and mobile computers were connected to the network. Although the Internet was widely used by academia since the 1980s, the commercialization incorporated its services and technologies into virtually every aspect of modern life.
Internet use grew rapidly in the West from the mid-1990s and from the late 1990s in the developing world. In the 20 years since 1995, Internet use has grown 100-times, measured for the period of one year, to over one third of the world population. Most traditional communications media, including telephony, radio, television, paper mail and newspapers are being reshaped or redefined by the Internet, giving birth to new services such as email, Internet telephony, Internet television music, digital newspapers, and video streaming websites. Newspaper, book, and other print publishing are adapting to website technology, or are reshaped into blogging,web feeds and online news aggregates. The entertainment industry was initially the fastest growing segment on the Internet.[citation needed] The Internet has enabled and accelerated new forms of personal interactions through instant messaging,Internet forums, and social networking. Online shopping has grown exponentially both for major retailers and small businesses and entrepreneurs, as it enables firms to extend their "bricks and mortar" presence to serve a larger market or even sell goods and services entirely online. Business-to-business and financial services on the Internet affect supply chains across entire industries.
The Internet has no centralized governance in either technological implementation or policies for access and usage; each constituent network sets its own policies.[7] Only the over reaching definitions of the two principal name spaces in the Internet, the Internet Protocol address space and the Domain Name System (DNS), are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers (ICANN). The technical underpinning and standardization of the core protocols is an activity of the Internet Engineering Task Force (IETF), a non-profit organization of loosely affiliated international participants that anyone may associate with by contributing technical expertise.
Web browser
Internet Explorer
Internet Explorer was one of the most widely used web browsers, attaining a peak of about 95% usage share during 2002 and 2003. This came after Microsoft used bundling to win the first browser war against Netscape, which was the dominant browser in the 1990s. Its usage share has since declined with the launch of Firefox (2004) and Google Chrome (2008), and with the growing popularity of operating systems such as macOS, Linux, iOS and Android that do not run Internet Explorer. Estimates for Internet Explorer's overall market share range from 5.45% to 27.38% or by Stat Counter's numbers ranked 3rd, just after Firefox (or even as low as 6th when counting all platforms, after Opera (and behind Safari), as of August 2016(browser market share is notoriously difficult to calculate). Microsoft spent over US$100 million per year on Internet Explorer in the late 1990s, with over 1,000 people working on it by 1999.
Versions of Internet Explorer for other operating systems have also been produced, including Internet Explorer for Mac andInternet Explorer for UNIX (Solaris and HP-UX), an Xbox 360 version called Internet Explorer for Xbox and an embedded OEM version called Pocket Internet Explorer, later rebranded Internet Explorer Mobile made for Windows Phone, Windows CE, and previously, based on Internet Explorer 7 for Windows Mobile.
On March 17, 2015, Microsoft announced that Microsoft Edge will replace Internet Explorer as the default browser on its Windows 10 devices. This effectively makes Internet Explorer 11 the last release. Internet Explorer will, however, remain on some versions of Windows 10 primarily for enterprise purposes. Starting January 12, 2016, only Internet Explorer 11 is supported
The browser has been scrutinized throughout its development for use of third-party technology (such as the source code of Spyglass Mosaic, used without royalty in early versions) and security and privacy vulnerabilities, and the United States and the European Union have alleged that integration of Internet Explorer with Windows has been to the detriment of fair browser competition with more security than older versions, according to Microsoft. Support varies based on the operating system's technical capabilities and its support life cycle.
Internet address
IP address
IP versions
Subnetting
In the early stages of development of the Internet Protocol, network administrators interpreted an IP address in two parts: network number portion and host number portion. The highest order octet (most significant eight bits) in an address was designated as the network number and the remaining bits were called the rest field or host identifier and were used for host numbering within a network.
This early method soon proved inadequate as additional networks developed that were independent of the existing networks already designated by a network number. In 1981, the Internet addressing specification was revised with the introduction of classful network architecture.
Classful network design allowed for a larger number of individual network assignments and fine-grained subnetwork design. The first three bits of the most significant octet of an IP address were defined as the class of the address. Three classes (A, B, and C) were defined for universal unicast addressing. Depending on the class derived, the network identification was based on octet boundary segments of the entire address. Each class used successively additional octets in the network identifier, thus reducing the possible number of hosts in the higher order classes (B and C). The following table gives an overview of this now obsolete system.
Classful network design served its purpose in the startup stage of the Internet, but it lacked scalability in the face of the rapid expansion of the network in the 1990s. The class system of the address space was replaced with Classless Inter-Domain Routing (CIDR) in 1993. CIDR is based on variable-length subnet masking (VLSM) to allow allocation and routing based on arbitrary-length prefixes.
Today,remnants of classful network concepts function only in a limited scope as thedefault configuration parameters of some network software and hardwarecomponents (e.g. netmask), and in the technical jargon used in network administrators'discussions.
Private
addresses
Private
addresses
IP subnetworks
IP address
assignment
Methods
Uses of
dynamic address assignment
Sticky
dynamic IP address
Address
autoconfiguration
Uses of
static addressing
Conflict
Routing
Unicast
addressing
Multicast
addressing
Anycast
addressing
Public address
Modifications to IP
addressing
IP
blocking and firewalls
IP
address translation
The World Wide Web (abbreviated WWW or the Web) is an information space where documents and other web resources are identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and can be accessed via the Internet.[1]English scientist Tim Berners-Lee invented the World Wide Web in 1989. He wrote the first web browser computer programme in 1990 while employed at CERN in Switzerland.
Electronic mail, or email, is a method of exchanging digital messages between people using digital devices such as computers, tablets and mobile phones. Email first entered substantial use in the 1960s and by the mid-1970s had taken the form now recognized as email. Email operates across computer networks, which in the 2010s is primarily the Internet. Some early email systems required the author and the recipient to both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simultaneously; they need to connect only briefly, typically to a mail server or a webmail interface, for as long as it takes to send or receive messages.Originally an ASCII text-only communications medium, Internet email was extended by Multipurpose Internet Mail Extensions (MIME) to carry text in other character sets and multimedia content attachments. International email, with internationalized email addresses using UTF-8, has been standardized, but as of 2016 it has not been widely adopted.[citation needed]The history of modern Internet email services reaches back to the early ARPANET, with standards for encoding email messages published as early as 1973 (RFC 561). An email message sent in the early 1970s looks very similar to a basic email sent today. Email played an important part in creating the Internet, and the conversion from ARPANET to the Internet in the early 1980s produced the core of the current services.
Classful network design allowed for a larger number of individual network assignments and fine-grained subnetwork design. The first three bits of the most significant octet of an IP address were defined as the class of the address. Three classes (A, B, and C) were defined for universal unicast addressing. Depending on the class derived, the network identification was based on octet boundary segments of the entire address. Each class used successively additional octets in the network identifier, thus reducing the possible number of hosts in the higher order classes (B and C). The following table gives an overview of this now obsolete system.
Historical classful
network architecture
|
|||||||
Class
|
Leading
bits |
Size of network
number bit field |
Size of rest
bit field |
Number
of networks |
Addresses
per network |
Start address
|
End address
|
A
|
0
|
8
|
24
|
128 (27)
|
16,777,216 (224)
|
0.0.0.0
|
127.255.255.255
|
B
|
10
|
16
|
16
|
16,384 (214)
|
65,536 (216)
|
128.0.0.0
|
191.255.255.255
|
C
|
110
|
24
|
8
|
2,097,152 (221)
|
256 (28)
|
192.0.0.0
|
223.255.255.255
|
Classful network design served its purpose in the startup stage of the Internet, but it lacked scalability in the face of the rapid expansion of the network in the 1990s. The class system of the address space was replaced with Classless Inter-Domain Routing (CIDR) in 1993. CIDR is based on variable-length subnet masking (VLSM) to allow allocation and routing based on arbitrary-length prefixes.
Today,remnants of classful network concepts function only in a limited scope as thedefault configuration parameters of some network software and hardwarecomponents (e.g. netmask), and in the technical jargon used in network administrators'discussions.
Private
addresses
Early
network design, when global end-to-end connectivity was envisioned for
communications with all Internet hosts, intended that IP addresses be uniquely
assigned to a particular computer or device. However, it was found that this
was not always necessary as private
networks developed
and public address space needed to be conserved.
Computers
not connected to the Internet, such as factory machines that communicate only
with each other via TCP/IP, need not have globally unique IP addresses. Three
non-overlapping ranges of IPv4 addresses for private networks were reserved in RFC 1918. These
addresses are not routed on the Internet and thus their use need not be
coordinated with an IP address registry.
Today,
when needed, such private networks typically connect to the Internet through network address translation (NAT).
IANA-reserved private
IPv4 network ranges
|
|||
Start
|
End
|
No. of addresses
|
|
24-bit block (/8 prefix, 1 × A)
|
10.0.0.0
|
10.255.255.255
|
16777216
|
20-bit block (/12 prefix, 16 × B)
|
172.16.0.0
|
172.31.255.255
|
1048576
|
16-bit block (/16 prefix, 256 × C)
|
192.168.0.0
|
192.168.255.255
|
65536
|
Any
user may use any of the reserved blocks. Typically, a network administrator
will divide a block into subnets; for
example, many home routers automatically
use a default address range of 192.168.0.0 through 192.168.0.255
(192.168.0.0/24).
IPv4 address exhaustion
Highlevels of demand have decreased the supply of unallocated Internet Protocol Version 4 (IPv4) addresses available for assignmentto Internet service providers and end user organizations since the 1980s.This development is referred to as IPv4 address exhaustion. IANA's primary addresspool wasexhausted on 3 February 2011, when the last five blocks were allocated to thefive RIRs. APNIC was the first RIR to exhaust its regionalpool on 15 April 2011, except for a small amount of address space reserved forthe transition to IPv6, intended to be allocated in a restricted process.
IPv6 addresses
The
rapid exhaustion of IPv4 address space prompted the Internet Engineering Task
Force (IETF)
to explore new technologies to expand the addressing capability in the
Internet. The permanent solution was deemed to be a redesign of the Internet
Protocol itself. This new generation of the Internet Protocol was eventually
named Internet Protocol Version 6 (IPv6) in 1995. The address size was increased from 32 to
128 bits (16 octets), thus
providing up to 2128 (approximately3.403×1038)
addresses. This is deemed sufficient for the foreseeable future.
The
intent of the new design was not to provide just a sufficient quantity of
addresses, but also redesign routing in the Internet by more efficient
aggregation of subnetwork routing prefixes. This resulted in slower growth of
routing tables in routers. The smallest possible individual allocation is a
subnet for 264 hosts,
which is the square of the size of the entire IPv4 Internet. At these levels,
actual address utilization rates will be small on any IPv6 network segment. The
new design also provides the opportunity to separate the addressing
infrastructure of a network segment, i.e. the local administration of the
segment's available space, from the addressing prefix used to route traffic to
and from external networks. IPv6 has facilities that automatically change the
routing prefix of entire networks, should the global connectivity or the
routing policy change, without requiring internal redesign or manual
renumbering.
The
large number of IPv6 addresses allows large blocks to be assigned for specific
purposes and, where appropriate, to be aggregated for efficient routing. With a
large address space, there is no need to have complex address conservation
methods as used in CIDR.
All
modern desktop and enterprise server operating systems include native support
for the IPv6 protocol, but it is not yet widely deployed in other devices, such
as residential networking routers, voice
over IP (VoIP)
and multimedia equipment, and network peripherals.
Private
addresses
Just
as IPv4 reserves addresses for private networks, blocks of addresses are set
aside in IPv6. In IPv6, these are referred to as unique local addresses (ULA). RFC 4193reserves
the routing prefix fc00::/7 for this block which is divided into two /8 blocks
with different implied policies. The addresses include a 40-bit pseudorandom
number that minimizes the risk of address collisions if sites merge or packets
are misrouted.
Early
practices used a different block for this purpose (fec0::), dubbed site-local
addresses. However, the definition of what constituted sites remained unclear and the poorly defined
addressing policy created ambiguities for routing. This address type was
abandoned and must not be used in new systems.
Addresses
starting with fe80:, called link-local addresses,
are assigned to interfaces for communication on the attached link. The
addresses are automatically generated by the operating system for each network
interface. This provides instant and automatic communication between all IPv6
host on a link. This feature is required in the lower layers of IPv6 network
administration, such as for the Neighbor Discovery Protocol.
Private
address prefixes may not be routed on the public Internet.
IP subnetworks
IP
networks may be divided into subnetworks in both IPv4 and IPv6. For this purpose, an IP
address is logically recognized as consisting of two parts: the network prefix and thehost identifier, or interface identifier (IPv6). The subnet mask or the
CIDR prefix determines how the IP address is divided into network and host
parts.
The
term subnet
mask is only
used within IPv4. Both IP versions however use the CIDR concept and notation.
In this, the IP address is followed by a slash and the number (in decimal) of
bits used for the network part, also called the routing prefix. For
example, an IPv4 address and its subnet mask may be 192.0.2.1 and
255.255.255.0, respectively. TheCIDR
notation for the
same IP address and subnet is 192.0.2.1/24, because the first 24 bits of the IP
address indicate the network and subnet.
IP address
assignment
Internet
Protocol addresses are assigned to a host either anew at the time of booting,
or permanently by fixed configuration of its hardware or software. Persistent
configuration is also known as using a static
IP address. In contrast, in situations when the computer's IP address is
assigned newly each time, this is known as using a dynamic IP address.
Methods
Static
IP addresses are manually assigned to a computer by an administrator. The exact
procedure varies according to platform. This contrasts with dynamic IP
addresses, which are assigned either by the computer interface or host software
itself, as in Zeroconf, or
assigned by a server using Dynamic Host Configuration
Protocol (DHCP).
Even though IP addresses assigned using DHCP may stay the same for long periods
of time, they can generally change. In some cases, a network administrator may
implement dynamically assigned static IP addresses. In this case, a DHCP server
is used, but it is specifically configured to always assign the same IP address
to a particular computer. This allows static IP addresses to be configured
centrally, without having to specifically configure each computer on the
network in a manual procedure.
In
the absence or failure of static or stateful (DHCP) address configurations, an
operating system may assign an IP address to a network interface using
state-less auto-configuration methods, such as Zeroconf.
Uses of
dynamic address assignment
IP
addresses are most frequently assigned dynamically on LANs and broadband
networks by the Dynamic Host Configuration
Protocol (DHCP).
They are used because it avoids the administrative burden of assigning specific
static addresses to each device on a network. It also allows many devices to
share limited address space on a network if only some of them will be online at
a particular time. In most current desktop operating systems, dynamic IP
configuration is enabled by default so that a user does not need to manually
enter any settings to connect to a network with a DHCP server. DHCP is not the
only technology used to assign IP addresses dynamically. Dialup and some
broadband networks use dynamic address features of the Point-to-Point Protocol.
Sticky
dynamic IP address
A sticky dynamic IP address is an informal term used by cable and DSL
Internet access subscribers to describe a dynamically assigned IP address which
seldom changes. The addresses are usually assigned with DHCP. Since the modems
are usually powered on for extended periods of time, the address leases are
usually set to long periods and simply renewed. If a modem is turned off and
powered up again before the next expiration of the address lease, it will most
likely receive the same IP address.
Address
autoconfiguration
RFC 3330 defines an address block, 169.254.0.0/16,
for the special use in link-local addressing for IPv4 networks. In IPv6, every interface, whether using static or dynamic address assignments,
also receives a local-link address automatically in the block fe80::/10.
These
addresses are only valid on the link, such as a local network segment or
point-to-point connection, that a host is connected to. These addresses are not
routable and like private addresses cannot be the source or destination of
packets traversing the Internet.
When
the link-local IPv4 address block was reserved, no standards existed for
mechanisms of address autoconfiguration. Filling the void, Microsoft created an implementation that is called
Automatic Private IP Addressing (APIPA).
APIPA has been deployed on millions of machines and has, thus, become a de facto
standard in the
industry. In RFC 3927, the IETF defined
a formal standard for this functionality.
Uses of
static addressing
Some
infrastructure situations have to use static addressing, such as when finding
the Domain Name System (DNS)
host that will translate domain
names to IP
addresses. Static addresses are also convenient, but not absolutely necessary,
to locate servers inside an enterprise. An address obtained from a DNS server
comes with a time to
live, or caching time, after which it should be looked up to
confirm that it has not changed. Even static IP addresses do change as a result
of network administration (RFC 2072).
Conflict
An
IP address conflict occurs when two devices on the same local physical or
wireless network claim to have the same IP address – that is, they conflict
with each other. Since only one of the devices is supposed to be on the network
at a time, the second one to arrive will generally stop the IP functionality of
one or both of the devices. In many cases with modern Operating
Systems, the Operating System will notify the user of one of the
devices that there is an IP address conflict (displaying the symptom error
message) and
then either stop functioning on the network or function very poorly on the
network. If one of the devices is the gateway, the network will be crippled.
Since IP addresses are assigned by multiple people and systems in multiple
ways, any of them can be at fault.
Routing
IP
addresses are classified into several classes of operational characteristics:
unicast, multicast, anycast and broadcast addressing.
Unicast
addressing
The
most common concept of an IP address is in unicast addressing, available in both IPv4 and IPv6. It normally refers to a single sender or a single receiver,
and can be used for both sending and receiving. Usually, a unicast address is
associated with a single device or host, but a device or host may have more
than one unicast address. Some individual PCs have several distinct unicast
addresses, each for its own distinct purpose. Sending the same data to multiple
unicast addresses requires the sender to send all the data many times over,
once for each recipient.
Broadcast addressing
In
IPv4 it is possible to send data to all possible destinations ("all-hosts
broadcast"), which permits the sender to send the data only once, and all
receivers receive a copy of it. In the IPv4 protocol, the address
255.255.255.255 is used for local broadcast. In addition, a directed (limited)
broadcast can be made by combining the network prefix with a host suffix
composed entirely of binary 1s. For example, the destination address used for a
directed broadcast to devices on the 192.0.2.0/24 network is 192.0.2.255. IPv6
does not implement broadcast addressing and replaces it with multicast to the
specially-defined all-nodes multicast address.
Multicast
addressing
A multicast
address is associated
with a group of interested receivers. In IPv4, addresses 224.0.0.0 through
239.255.255.255 (the former Class D addresses) are designated as multicast
addresses. IPv6 uses the address block with the prefix
ff00::/8 for multicast applications. In either case, the sender sends a single
datagram from its unicast address to the multicast group address and the
intermediary routers take care of making copies and sending them to all
receivers that have joined the corresponding multicast group.
Anycast
addressing
Like
broadcast and multicast, anycast is a one-to-many routing topology. However,
the data stream is not transmitted to all receivers, just the one which the
router decides is logically closest in the network. Anycast address is an
inherent feature of only IPv6. In IPv4, anycast addressing implementations
typically operate using the shortest-path metric ofBGP routing and do
not take into account congestion or other attributes of the path. Anycast
methods are useful for global load balancing and are commonly used in
distributedDNS systems.
Public address
A
public IP address, in common parlance, is a globally routable unicast IP
address, meaning that the address is not an address reserved for use in private
networks, such as those reserved by RFC 1918, or
the various IPv6 address formats of local scope or site-local scope, for
example for link-local addressing. Public IP addresses may be
used for communication between hosts on the global Internet.
Modifications to IP
addressing
IP
blocking and firewalls
Firewalls perform Internet
Protocol blocking to
protect networks from unauthorized access. They are common on today's Internet.
They control access to networks based on the IP address of a client computer.
Whether using a blacklist or a whitelist, the
IP address that is blocked is the perceived IP address of the client, meaning
that if the client is using aproxy
server or network address translation,
blocking one IP address may block many individual computers.
IP
address translation
Multiple
client devices can appear to share IP addresses: either because they are part
of a shared
hosting web
server environment
or because an IPv4 network address translator(NAT)
or proxy
server acts as
an intermediary agent on behalf of its customers, in which
case the real originating IP addresses might be hidden from the server
receiving a request. A common practice is to have a NAT hide a large number of
IP addresses in a private
network. Only the "outside" interface(s) of the NAT need to
have Internet-routable addresses.
Most
commonly, the NAT device maps TCP or UDP port numbers on the side of the
larger, public network to individual private addresses on the masqueraded
network.
In
small home networks, NAT functions are usually implemented in a residential gateway device,
typically one marketed as a "router". In this scenario, the computers
connected to the router would have private IP addresses and the router would
have a public address to communicate on the Internet. This type of router
allows several computers to share one public IP address.
Internet service provider
"ISP" redirects here.
For other uses, see ISP (disambiguation).
"Internet service"
redirects here. It is not to be confused with Web service.
Internet
connectivity options from end-user to tier 3/2 ISPs
An Internet service provider (ISP) is an organization that
provides services for accessing and using the Internet.
Internet service providers may be organized in various forms, such as
commercial,community-owned, non-profit, or
otherwise privately
owned.
Internet
services typically provided by ISPs include Internet
access, Internet transit, domain
name registration, web hosting, Usenet service, and colocation.
Internet services
World Wide Web
The World Wide Web has been central to thedevelopment of the Information Age and is the primary toolbillions of people use to interact on the Internet.[4][5][6] Web pages are primarily text documents formatted and annotated with Hypertext MarkupLanguage (HTML). In addition toformatted text, web pages may contain images, video, audio, and software components that are rendered in the user's web browser as coherent pages of multimedia content. Embedded hyperlinks permit users tonavigate between web pages.Multiple web pages with a common theme, a common domain name, or both, make up awebsite. Website content can largely be provided by thepublisher, or interactive where users contribute content or the content dependsupon the user or their actions. Websites may be mostly informative, primarilyfor entertainment, or largely for commercial, governmental, or non-governmentalorganisational purposes. In the 2006 Great British Design Quest organised bythe BBC and the Design Museum, the World Wide Web was voted among the top 10British design icons.
Email.
 |
| The symbol used for email |
Social network
A social network is a social structure made up of a set of social actors (such as
individuals or organizations), sets of dyadic ties, and other social interactions between actors. The
social network perspective provides a set of methods for analyzing the
structure of whole social entities as well as a variety of theories explaining
the patterns observed in these structures.[1] The study of these
structures uses social network analysis to identify local and
global patterns, locate influential entities, and examine network dynamics.
Social networks and the analysis of them is an inherently interdisciplinary academic field which emerged from social psychology,sociology, statistics, and graph theory. Georg Simmel authored early structural theories in sociology emphasizing the dynamics of triads and "web of group affiliations". Jacob Moreno is credited with developing the first sociograms in the 1930s to study interpersonal relationships. These approaches were mathematically formalized in the 1950s and theories and methods of social networks became pervasive in the social and behavioral sciences by the 1980s. Social network analysis is now one of the major paradigms in contemporary sociology, and is also employed in a number of other social and formal sciences. Together with other complex networks, it forms part of then ascent field of network science.Surfing to the Internet
Introduction:
Surfing the Internet is a term typically used to describe an undirected type of web of browsing where users whimsically follow one interesting link to another without a planned search strategy or definite objective. Surfing the net has become a popular pastime, for many Internet users.
Surfing the Internet' is not to be confused with the phrase 'browsing the Internet' which refers to exploring the web with a clear-cut objective but without any planned search strategies. Searching the web refers to exploring the Internet with a definite in both strategy and objective.
Surfing the Internet has been likened to the ironic term 'channel surfing', which is used to describe randomly changing TV channels. Its only relation to actual surfboarding has to do with the notion of 'going with flow' when surfing.
For more details about Internet surfing click the link bellow:
Using search engine
Introduction
You do not always have to know a website’s address in order to use the Internet. It is important to know how to search for information. One of the best methods to search is to use a search engine. A search engine is a software system on the Internet that will conduct a search of its own database of websites based on terms you have entered. As a result, you will be shown a list of web addresses that contain the term you were looking to find. An example of a popular search engine is www.google.com.
How to Use Google
First you will need to open Internet Explorer then enter www.google.com in the address bar. Here is what www.google.com looks like:
To conduct the search, point and click your mouse in the search textbox. Type in the textbox the words or words you would like to search. Then point and click your mouse on the Google Searchbutton below the search textbox.
Every phrase in either blue with an underline may be clicked on to visit that particular site. These are hyperlinks to websites. The websites deemed most fitting for the search are found at the near the top of the list. There are also paid sponsors found at the top (shaded) and to the right of the screen that you may visit if you wish. You can see actual web addresses in green text.
In addition, notice the results area:
These results are found on the top right of the page. 233,000,000 would be impossible to go through therefore you will need to learn ways to reduce the amount of results. To continue reviewing the search results pages, scroll to the bottom of the Google webpage until you see:
Important Notes:
You may not always get the results you are looking for so you will need to play with searchable terms. Using more words in combination, and especially more specific words will help. Be aware that not all websites that are found in the results are appropriate to your search. Read the blurb under the result name on the list before you click. In addition, do not click on anything that seems inappropriate, too good to be true, or dangerous. Use your gut instinct before you click. There are many websites out there on the Internet that will mislead and try to take advantage of beginners. Use caution.
Additional contents for finding Information on the Internet
Using Search Engines
There is an enormous
amount of information on the Web! However, there's an easy way for you to find
specific information without searching through every site yourself. Just use a
search engine. Here are some tips to help you make the most of search engines
How to Use a Search Engine
Most search engines
work the same basic way. You type into a search box the information you're
looking for and PRESTO! the search engine lists Web sites that contain this
information. These results are known as "hits." The words you type
into the search box are called "keywords." The keywords you use will
greatly affect your results. Other search engines, like Ask Jeeves for Kids,
let you type in questions without having to choose keywords.
Four Tips to Help Make the Most of a Search
1. Make your keywords as
precise as possible. If you're looking for
information on Tyrannosaurus rex, don't type in "dinosaurs." You'll
get too much general information about dinosaurs and not enough specific hits
about T-rex.
2. Use two or more
keywords in your search. But put the most
important keywords first. For example, if you wanted information about what the
T-rex ate, you might use the following keywords in this order: Tyrannosaurus
rex diet. The search engine will look for Web pages that contain all these
words.
3. Make sure you spell
the keywords correctly. If you typed
"dinasour" as a keyword, your search would turn up empty. If you're
not sure of a word's correct spelling, use a dictionary.
4. Always try more than
one search engine. Each search engine doesn't
look through every site on the Web. Instead, most search engines check Web site
pages every once in a while to create their own databases. So when you use a
search engine, you're actually looking at one small slice of sites. Different
search engines will usually come up with different results. So it makes sense
to use more than one.
Three Tips for Getting More Precise Hits
1. Use AND
Sometimes you may need to use more than one
keyword when searching, without making a phrase. You usually need to let the search
engine know whether you want to see sites that contain all the keywords or
whether it should find those in which just one of the words appears. If you
want to get results with all the keywords you type, then you should use
"AND" to let the search engine know. Make sure you use capital
letters when typing "AND."
Example: If you were searching for Web pages
about dinosaurs and lizards, you would type:
The search engine will list sites that contain
both words. Some search engines require a plus sign (+) instead of the word
AND. Then you would add a plus sign before any keyword that must appear in your
results:
2. Use OR
Let's say you perform a search using two
keywords. What can you do if you actually want to find Web sites in which
either one word or the other appears? You can use the word "OR." This
will let the search engine know you want Web sites that contain any of the
keywords you type in. For the best results, you should always enclose OR
searches in parentheses:
The search engine will list Web sites that
contain either keyword.
3. Use NOT
Sometimes by typing one keyword, you'll get
many results that have nothing to do with your topic. For example, if you
wanted to find Web sites about dinosaurs, but not dinosaur fossils, you could
type this into the search box:
The search engine will look for Web pages that
contain the word "dinosaur." But if the page contains the word
"fossil," the search engine will not list it. Some search engines
require you to use a minus sign (-) in place of the word NOT. You would then
add a minus sign in front of any word that you didn't want to appear in your
results.
These types of searches are known as Boolean
searches. AND (+), OR, and NOT (-) are known as Boolean operators. They are
named after the British mathematician George Boole, who developed a system of
logic in the 1800s.
0 comments:
Post a Comment