World Wide Web
World Wide
Web
The World
Wide Web (WWW) is an open source information space where
documents and other web resources are
identified by URLs, interlinked by hypertext links, and can be accessed
via the Internet. The World
Wide Web was invented by English scientist Tim Berners-Lee in
1989. He wrote the first web browser in 1990 while employed at CERN in Switzerland.
It
has become known simply as the Web. The World Wide Web was central to the
development of the Information Age and
is the primary tool billions of people use to interact on the Internet.
Web pages are primarily text documents formatted and
annotated with Hypertext Markup Language (HTML).
In addition to formatted text, web pages may contain images, video, and software components that are
rendered in the user's web browser as
coherent pages of multimedia content.
Embedded hyperlinks permit
users to navigate between web pages. Multiple web pages with a
common theme, a common domain name, or both, may
be called a website. Website content can largely be
provided by the publisher, or interactive where users contribute content or the
content depends upon the user or their actions. Websites may be mostly
informative, primarily for entertainment, or largely for commercial purposes.
Domain
name extensions and their meaning
|
Extensions
|
|
.aero
.biz
.com (.co in UK)
.coop
.edu (.ac in UK)
.gov
.info
.int
.mil
.museum
.name
.net
.org
.pro
|
|
Meaning
|
|
Aviation
industry
Businesses
Commercial
Cooperatives
Educational
and research
government
general
use
international
organization
military
agency
museums
individuals
gateway
or host
non-profit
organization
professionals
|
|
Suggested
extension
|
Meaning
|
|
.firm
.store
.web
.arts
.rec
.info
.nom
|
Firm
or agency
Online
retail shop
Web-related
Cultural
or entertainment
Recreational
Informative
personal
|
History
Berners-Lee's
vision of a global hyperlinked information system became a possibility by the
second half of the 1980s. By 1985 the global Internet began to proliferate in
Europe and in the Domain Name System (which the Uniform Resource Locator is built upon) came into
being. In 1988 the first direct IP connection between Europe and North America
was made and Berners-Lee began to openly discuss the possibility of a web-like
system at CERN.
In
March 1989 Tim Berners-Lee issued a proposal to the management at CERN for a
system called "Mesh" that referenced ENQUIRE, a database and software project
he had built in 1980, which used the term "web" and described a more
elaborate information management system based on links embedded in readable
text: "Imagine, then, the references in this document all being associated
with the network address of the thing to which they referred, so that while
reading this document you could skip to them with a click of the mouse."
Such a system, he explained, could be referred to using one of the existing
meanings of the word hypertext, a term that he says was coined in
the 1950s. There is no reason, the proposal continues, why such hypertext links
could not encompass multimedia documents including graphics, speech and video,
so that Berners-Lee goes on to use the term hypermedia.
With
help from his colleague and fellow hypertext enthusiast Robert Cailliau he
published a more formal proposal on 12 November 1990 to build a "Hypertext
project" called "World Wide Web" (one word) as a "web"
of "hypertext documents" to be viewed by "browsers" using
a client–server architecture. At this point HTML and HTTP
had already been in development for about two months and the first Web server
was about a month from completing its first successful test.
This
proposal estimated that a read-only web would be developed within three months
and that it would take six months to achieve "the creation of new links
and new material by readers, [so that] authorship becomes universal" as
well as "the automatic notification of a reader when new material of
interest to him/her has become available." While the read-only goal was
met, accessible authorship of web content took longer to mature, with the wiki concept, WebDAV, blogs, Web 2.0 and RSS/Atom.
The
proposal was modeled after the SGML reader Dynatext by Electronic Book
Technology, a spin-off from the Institute for
Research in Information and Scholarship at Brown University.
The Dynatext system, licensed by CERN, was a key player in the extension of
SGML ISO 8879:1986 to Hypermedia within HyTime, but it was considered too
expensive and had an inappropriate licensing policy for use in the general high
energy physics community, namely a fee for each document and each document
alteration.
A NeXT Computer was used
by Berners-Lee as the world's first web server and also
to write the first web browser, World Wide Web,
in 1990. By Christmas 1990, Berners-Lee had built all the tools necessary for a
working Web: the first web browser (which
was a web editor as well) and the first web server. The first web
site, which described the project itself, was published on 20 December
1990.
The
first web page may be lost, but Paul Jones of UNC-Chapel Hill in
North Carolina announced in May 2013 that Berners-Lee gave him what he says is
the oldest known web page during a 1991 visit to UNC. Jones stored it on
a magneto-optical drive and on his NeXT computer.
On
6 August 1991, Berners-Lee published a short summary of the World Wide Web
project on the newsgroup alt.
hypertext. This date also marked the debut of the Web as a publicly available
service on the Internet, although new users only accessed it after 23 August.
For this reason this is considered the internet’s day. Several news media
have reported that the first photo on the Web was published by Berners-Lee in
1992, an image of the CERN house band Les Horrible Cernettes taken by Silvano de Genaro;
Genaro has disclaimed this story, writing that media were "totally
distorting our words for the sake of cheap sensationalism.
The
first server outside Europe was installed at the Stanford Linear Accelerator Center (SLAC) in Palo Alto,
California, to host the SPIRES-HEP database. Accounts differ
substantially as to the date of this event. The World Wide Web Consortium's
timeline says December 1992, whereas SLAC itself claims December 1991, as does
a W3C document titled A Little History of the World Wide Web.
The
underlying concept of hypertext originated in previous projects from the 1960s,
such as the Hypertext Editing System (HES) at Brown University, Nelson’s Project,
and Douglas Engelbart's oN-Line System (NLS). Both Nelson and Engelbart were in turn
inspired by Vannevar Bush's microfilm-based memex, which was described in the 1945
essay "As We May Think".
Berners-Lee's
breakthrough was to marry hypertext to the Internet. In his book weaving the Web,
he explains that he had repeatedly suggested that a marriage between the two
technologies was possible to members of both technical communities,
but when no one took up his invitation, he finally assumed the project himself.
In the process, he developed three essential technologies:
·
a
system of globally unique identifiers for resources on the Web and elsewhere,
the universal document identifier (UDI), later known as uniform resource locator(URL) and uniform resource identifier (URI);
The
World Wide Web had a number of differences from other hypertext systems
available at the time. The Web required only unidirectional links rather than
bidirectional ones, making it possible for someone to link to another resource
without action by the owner of that resource. It also significantly reduced the
difficulty of implementing web servers and browsers (in comparison to earlier
systems), but in turn presented the chronic problem of link rot.
Unlike
predecessors such as HyperCard, the World Wide Web was
non-proprietary, making it possible to develop servers and clients
independently and to add extensions without licensing restrictions. On 30 April
1993, CERN announced that the World Wide Web would be free to anyone, with no
fees due. Coming two months after the announcement that the server
implementation of the Gopher protocol was no longer free
to use, this produced a rapid shift away from Gopher and towards the Web. An
early popular web browser was ViolaWWW for UNIX and the X Windowing System.
Robert Cailliau,
Jean-François Abramatic formerly of INRIA, and Tim Berners-Lee at
the 10th anniversary of the World Wide Web Consortium.
Scholars
generally agree that a turning point for the World Wide Web began with the
introduction of the Mosaic web
browser in
1993, a graphical browser developed by a team at the National Center
for Supercomputing Applications at
the University (NCSA-UIUC), led by Marc Andreessen. Funding
for Mosaic came from the U.S. High-Performance Computing and Communications
Initiative and the High
Performance Computing and Communication Act of 1991, one of several computing developments
initiated by U.S. Senator Al Gore. Prior
to the release of Mosaic, graphics were not commonly mixed with text in web
pages and the web's popularity was less than older protocols in use over the
Internet, such as Gopher and Wide Area Information Servers (WAIS). Mosaic's graphical
user interface allowed the Web to become, by far, the most popular Internet
protocol.
The World Wide Web Consortium (W3C) was founded by Tim
Berners-Lee after he left the European Organization for Nuclear Research (CERN)
in October 1994. It was founded at the Massachusetts Institute of Technology Laboratory for Computer
Science (MIT/LCS) with support from the Defense
Advanced Research Projects Agency (DARPA),
which had pioneered the Internet; a year later, a second site was founded
at INRIA (a French national computer
research lab) with support from the
European DG InfSo; and in 1996, a
third continental site was created in Japan at Keio University.
By the end of 1994, the total number of websites was still relatively small,
but many notable websites were already active that
foreshadowed or inspired today's most popular services.
Connected
by the existing Internet, other websites were created around the world, adding
international standards for domain names and HTML. Since then, Berners-Lee has
played an active role in guiding the development of web standards (such as
the markup languages to
compose web pages in), and has advocated his vision of a Semantic Web. The World
Wide Web enabled the spread of information over the Internet through an
easy-to-use and flexible format. It thus played an important role in
popularizing use of the Internet. Although the two terms are
sometimes conflated in
popular use, World Wide Web is not synonymous with Internet. The
Web is an information space containing hyperlinked documents and other resources, identified
by their URIs. It is implemented as both client and server software using
Internet protocols such as TCP/IP and HTTP.
Tim
Berners-Lee was knighted in 2004 by Queen Elizabeth II for
"services to the global development of the Internet.
Functions
The World Wide Web functions as a layer on top of the
Internet, helping to make it more functional. The advent of the Mosaic web
browser helped to make the web much more usable.
The
terms Internet and World Wide Web are often used without
much distinction. However, the two are not the same. The Internet is a global
system of interconnected computer networks.
In contrast, the World Wide Web is one of the services transferred over these
networks. It is a collection of text documents and other resources, linked by
hyperlinks and URLs, usually accessed by web browsers, from web
servers.
Viewing
a web page on the
World Wide Web normally begins either by typing the URL of the page into a web browser, or by following a
hyperlink to that page or resource. The web browser then initiates a series of
background communication messages to fetch and display the requested page. In
the 1990s, using a browser to view web pages—and to move from one web page to
another through hyperlinks—came to be known as 'browsing,' 'web surfing'
(after channel surfing),
or 'navigating the Web'. Early studies of this new behavior investigated user
patterns in using web browsers. One study, for example, found five user
patterns: exploratory surfing, window surfing, evolved surfing, bounded
navigation and targeted navigation.
The
following example demonstrates the functioning of a web browser when accessing
a page at the URLhttp://www.example.org/home.html. The
browser resolves the server name of the URL (www.example.org)
into an Internet using the globally distributed Domain Name System (DNS). This lookup returns an IP address such
as 203.0.113.4 or 2001:db8:2e: 7334. The browser then requests
the resource by sending an HTTP request across the Internet to the computer at
that address. It requests service from a specific TCP port number that is well
known for the HTTP service, so that the receiving host can distinguish an HTTP
request from other network protocols it may be servicing. The HTTP protocol
normally uses port number 80. The content of the HTTP request
can be as simple as two lines of text:
GET
/home.html HTTP/1.1
Host:
www.example.org
The
computer receiving the HTTP request delivers it to web server software
listening for requests on port 80. If the web server can fulfill the request it
sends an HTTP response back to the browser indicating success:
HTTP/1.0
200 OK
Content-Type:
text/html; charset=UTF-8
followed
by the content of the requested page. Hypertexts Markup Language (HTML) for a basic web page might look
like this:
<html>
<head>
<title>Example.org – The World Wide
Web</title>
</head>
<body>
<p>The World Wide Web, abbreviated as
WWW and commonly known ...</p>
</body>
</html>
The
web browser parses the HTML and interprets the
markup (<title>, <p> for paragraph, and
such) that surrounds the words to format the text on the screen. Many web pages
use HTML to reference the URLs of other resources such as images, other
embedded media, scripts that
affect page behavior, and Cascading Style Sheets that affect page layout. The
browser makes additional HTTP requests to the web server for these other Internet media types. As it receives their content from the web server, the
browser progressively renders the page onto the screen as
specified by its HTML and these additional resources.
Linking
Most
web pages contain hyperlinks to other related pages and perhaps to downloadable
files, source documents, definitions and other web resources. In the underlying
HTML, a hyperlink looks like this: <a href="http://www.example.org/home.html">Example.org
Homepage</a>
Graphic representation of a minute fraction of the WWW,
demonstrating hyperlinks
Such
a collection of useful, related resources, interconnected via hypertext links
is dubbed a web of information. Publication on the Internet created
what Tim Berners-Lee first called the Worldwide Web (in its
original Camel Case, which was subsequently discarded) in November 1990.[9]
The
hyperlink structure of the WWW is described by the web graph: the nodes of the web graph
correspond to the web pages (or URLs) the directed edges between them to the
hyperlinks.
Over
time, many web resources pointed to by hyperlinks disappear, relocate, or are
replaced with different content. This makes hyperlinks obsolete, a phenomenon
referred to in some circles as link rot, and the hyperlinks affected by it are
often called dead links. The
ephemeral nature of the Web has prompted many efforts to archive web sites.
The Internet Archive, active since 1996, is the best known of such efforts.
Dynamic updates of web pages
JavaScript is a scripting language that was initially developed
in 1995 by Brendan Eich, then
of Netscape, for use
within web pages. The standardized version is ECMAScript. To
make web pages more interactive, some web applications also use JavaScript
techniques such as Ajax (asynchronous JavaScript
and XML). Client-side script is delivered with the page that can make
additional HTTP requests to the server, either in response to user actions such
as mouse movements or clicks, or based on elapsed time. The server's responses
are used to modify the current page rather than creating a new page with each
response, so the server needs only to provide limited, incremental information.
Multiple Ajax requests can be handled at the same time, and users can interact
with the page while data is retrieved. Web pages may also regularly poll the server to check whether new information is
available.
WWW prefix
Many
hostnames used for the World Wide Web begin with www because of the
long-standing practice of naming Internet hosts according to the services they
provide. The hostname of
a web server is
often www, in the same way that it may be ftp for an FTP server,
and news or nntp for a USENET news server. These host
names appear as Domain Name System (DNS) or subdomain names, as
in www.example.com. The use of www is not required by any technical
or policy standard and many web sites do not use it; indeed, the first ever web
server was called nxoc01.cern.ch. According to Paolo
Palazzi, who worked at CERN along with Tim Berners-Lee, the popular use
of www as subdomain was accidental; the World Wide Web project page
was intended to be published at www.cern.ch while info.cern.ch was intended to
be the CERN home page, however the DNS records were never switched, and the
practice of prepending www to an institution's website domain name was
subsequently copied. Many established websites still use the prefix, or they
employ other subdomain names such as www2, secure or for
special purposes. Many such web servers are set up so that both the main domain
name (e.g., example.com) and the www subdomain (e.g.,
www.example.com) refer to the same site; others require one form or the other,
or they may map to different web sites.
The
use of a subdomain name is useful for load balancing incoming web traffic by
creating a CNAME record that
points to a cluster of web servers. Since, currently, only a subdomain can be
used in a CNAME, the same result cannot be achieved by using the bare domain
root.
When
a user submits an incomplete domain name to a web browser in its address bar
input field, some web browsers automatically try adding the prefix
"www" to the beginning of it and possibly ".com",
".org" and ".net" at the end, depending on what might be
missing. For example, entering 'Microsoft' may be transformed
tohttp://www.microsoft.com/ and 'open office'
to http://www.openoffice.org. This feature started appearing in early
versions of Mozilla Firefox, when it still had the working
title 'Firebird' in early 2003, from an earlier practice in browsers such
as Lynx. It
is reported that Microsoft was granted a US patent for the same idea in 2008,
but only for mobile devices.
In
English, www is usually read as double-u double-u
double-u. Some users pronounce it dub-dub-dub, particularly in New
Zealand. Stephen Fry, in his "Podgrammes" series of podcasts,
pronounces it wuh wuh wuh. The English writer Douglas Adams once
quipped in The Independent on Sunday (1999):
"The World Wide Web is the only thing I know of whose shortened form takes
three times longer to say than what it's short for". In Mandarin
Chinese, World Wide Web is commonly translated via a phono-semantic matching to wàn wéi wǎng (万维网), which
satisfies www and literally means "myriad dimensional
net", a translation that reflects the design concept and
proliferation of the World Wide Web. Tim Berners-Lee's web-space states
that World Wide Web is officially spelled as three separate words,
each capitalized, with no intervening hyphens.
Use
of the www prefix is declining as Web 2.0 web applications seek
to brand their domain names and make them easily pronounceable. As
the mobile web grows in
popularity, services like Gmail.com, Outlook.com, MySpace.com, Facebook.com and Twitter.com are most often mentioned
without adding "www." (or, indeed, ".com") to the domain.
Scheme
specifiers
The
scheme specifiers http:// and https:// at the start of a
web URI refer to Hypertext Transfer Protocol or HTTP Secure, respectively.
They specify the communication protocol to use for the request and response.
The HTTP protocol is fundamental to the operation of the World Wide Web, and
the added encryption layer in HTTPS is essential when browsers send or retrieve
confidential data, such as passwords or banking information. Web browsers
usually automatically prepend http:// to user-entered URIs, if omitted.
Web security
For criminals, the web has become the preferred
way to spread malware. Cybercrime on the web can include identity theft, fraud, espionage and intelligence gathering. Web-based vulnerabilities now outnumber traditional
computer security concerns, and as measured by Google, about one in ten web pages may
contain malicious code. Most web-based attacks take
place on legitimate websites, and most, as measured by Sophos, are hosted in the United States,
China and Russia. The most common of all malware threats is SQL injection attacks
against websites. Through HTML and URIs, the Web was vulnerable to attacks
like cross (XSS) that came with the introduction of
JavaScript and were exacerbated to some degree by Web 2.0 and Ajax web design that favors
the use of scripts. Today by one estimate, 70% of all websites are open to
XSS attacks on their users. Phishing is another common threat to
the Web. "SA, the Security Division of EMC, today announced the findings
of its January 2013 Fraud Report, estimating the global losses from phishing at
$1.5 Billion in 2012". Two of the well-known phishing methods are
Covert Redirect and Open Redirect.
Proposed
solutions vary to extremes. Large security vendors like McAfee already design governance and
compliance suites to meet post-9/11 regulations, and some, like Finjan have recommended active
real-time inspection of code and all content regardless of its
source. Some have argued that for enterprise to see security as a business
opportunity rather than a cost center, "ubiquitous, always-on digital
rights management" enforced in the infrastructure by a handful of
organizations must replace the hundreds of companies that today secure data and
networks. Jonathan Zittrain has said users sharing responsibility for
computing safety is far preferable to locking down the Internet.
Privacy
Every
time a client requests a web page, the server can identify the request's IP
address and usually logs it. Also, unless set not to do so, most web browsers
record requested web pages in a viewable history feature, and
usually cache much of the content locally.
Unless the server-browser communication uses HTTPS encryption, web requests and
responses travel in plain text across the Internet and can be viewed, recorded,
and cached by intermediate systems.
When
a web page asks for, and the user supplies, personally identifiable information—such as their real name, address,
e-mail address, etc.—web-based entities can associate current web traffic with
that individual. If the website uses HTTP cookies, username and
password authentication, or other tracking techniques, it can relate other web
visits, before and after, to the identifiable information provided. In this way
it is possible for a web-based organization to develop and build a profile of
the individual people who use its site or sites. It may be able to build a
record for an individual that includes information about their leisure
activities, their shopping interests, their profession, and other aspects of
their demographic profile. These profiles are obviously of potential interest to
marketers, advertisers and others. Depending on the website's terms and conditions and the local laws that apply information from
these profiles may be sold, shared, or passed to other organizations without
the user being informed. For many ordinary people, this means little more than
some unexpected e-mails in their in-box, or some uncannily relevant advertising
on a future web page. For others, it can mean that time spent indulging an
unusual interest can result in a deluge of further targeted marketing that may
be unwelcome. Law enforcement, counter terrorism and espionage agencies can
also identify, target and track individuals based on their interests or
proclivities on the Web.
Social networking sites
try to get users to use their real names, interests, and locations. They
believe this makes the social networking experience more realistic, and
therefore more engaging for all their users. On the other hand, uploaded
photographs or unguarded statements can be identified to an individual, who may
regret this exposure. Employers, schools, parents, and other relatives may be
influenced by aspects of social networking profiles that the posting individual
did not intend for these audiences. On-line bullies may
make use of personal information to harass or stalk users. Modern social
networking websites allow fine grained control of the privacy settings for each
individual posting, but these can be complex and not easy to find or use,
especially for beginners.
Photographs
and videos posted onto websites have caused particular problems, as they can
add a person's face to an on-line profile. With modern and potential facial recognition technology, it may then be possible to relate
that face with other, previously anonymous, images, events and scenarios that
have been imaged elsewhere. Because of image caching, mirroring and copying, it
is difficult to remove an image from the World Wide Web.
Standards
Many
formal standards and other technical specifications and software define the
operation of different aspects of the World Wide Web, the Internet, and
computer information exchange. Many of the documents are the work of the World
Wide Web Consortium (W3C), headed by Berners-Lee, but some are produced by
the Internet Engineering Task Force (IETF) and other
organizations.
Usually,
when web standards are discussed, the following publications are seen as
foundational:
·
Recommendations
for markup languages, especially HTML and XHTML, from the W3C. These define the
structure and interpretation of hypertext documents.
Additional
publications provide definitions of other essential technologies for the World
Wide Web, including, but not limited to, the following:
·
Uniform
Resource Identifier (URI), which is a universal system for referencing
resources on the Internet, such as hypertext documents and images. URIs, often
called URLs, are defined by the IETF's RFC 3986 / STD 66: Uniform Resource Identifier (URI):
Generic Syntax, as well as its predecessors and numerous URI scheme-defining RFCs;
·
Hypertexts
Transfer Protocol (HTTP), especially as defined by RFC 2616: HTTP/1.1 and RFC 2617: HTTP Authentication, which specify how the
browser and server authenticate each other.
Accessibility
There
are methods for accessing the Web in alternative mediums and formats to
facilitate use by individuals with disabilities. These disabilities may be
visual, auditory, physical, speech related, cognitive, neurological, or some
combination. Accessibility features also help people with temporary
disabilities, like a broken arm, or aging users as their abilities
change. The Web receives information as well as providing information and
interacting with society. The World Wide Web Consortium claims it essential
that the Web be accessible, so it can provide equal access and equal opportunity to
people with disabilities. Tim Berners-Lee once noted, "The power of
the Web is in its universality. Access by everyone regardless of disability is
an essential aspect." Many countries regulate web accessibility as
a requirement for websites. International cooperation in the W3C Web Accessibility Initiative led to simple guidelines that
web content authors as well as software developers can use to make the Web
accessible to persons who may or may not be using assistive technology.
Internationalization
The
W3C Internationalization Activity assures that web
technology works in all languages, scripts, and cultures. Beginning in
2004 or 2005, Unicode gained ground and eventually
in December 2007 surpassed both ASCII and Western European as the
Web's most frequently used character encoding. Originally RFC 3986allowed resources to be identified by URI in a subset of
US-ASCII. RFC 3987 allows
more characters—any character in the Universal Character Set—and now a resource can be
identified by IRI in any language.
Statistics
Between
2005 and 2010, the number of web users doubled, and was expected to surpass two
billion in 2010. Early studies in 1998 and 1999 estimating the size of the
Web using capture/recapture methods showed that much of the web was not indexed
by search engines and the Web was much larger than expected. According to a
2001 study, there was a massive number, over 550 billion, of documents on the
Web, mostly in the invisible Web, or Deep Web. A 2002 survey of 2,024 million web
pages determined that by far the most web content was in the English language:
56.4%; next were pages in German (7.7%), French (5.6%), and Japanese (4.9%). A
more recent study, which used web searches in 75 different languages to sample
the Web, determined that there were over 11.5 billion web pages in the publicly index able web as
of the end of January 2005. As of March 2009, the index able web contains
at least 25.21 billion pages. On 25 July 2008, Google software engineers
Jesse Alpert and Nissan Hajaj announced that Google Search had
discovered one trillion unique URLs. As of May 2009, over 109.5 million
domains operated. Of these, 74% were commercial or other domains operating
in the generic top-level domain com.
Statistics
measuring a website's popularity are usually based either on the number
of page views or on
associated server 'hits' (file requests) that it receives.
Speed issues
Frustration
over congestion issues
in the Internet infrastructure and the high latency that
results in slow browsing has led to a pejorative name for the World Wide Web:
the World Wide Wait. Speeding up the Internet is an ongoing
discussion over the use of peering and QoS technologies.
Other solutions to reduce the congestion can be found at W3C. Guidelines for web response times are:
·
0.1
second (one tenth of a second). Ideal response time. The user does not sense
any interruption.
·
1
second. Highest acceptable response time. Download times above 1 second
interrupt the user experience.
·
10
seconds. Unacceptable response time. The user experience is interrupted and the
user is likely to leave the site or system
Web caching
A web cache is a server computer located
either on the public Internet, or within an enterprise that stores recently
accessed web pages to improve response time for users when the same content is
requested within a certain time after the original request.
Most
web browsers also implement a browser cache for
recently obtained data, usually on the local disk drive. HTTP requests by a
browser may ask only for data that has changed since the last access. Web pages
and resources may contain expiration information to control caching to secure
sensitive data, such as in online banking,
or to facilitate frequently updated sites, such as news media. Even sites with
highly dynamic content may permit basic resources to be refreshed only
occasionally. Web site designers find it worthwhile to collate resources such
as CSS data and JavaScript into a few site-wide files so that they can be cached
efficiently.
Enterprise firewalls often
cache Web resources requested by one user for the benefit of many. Some search engines store
cached content of frequently accessed websites.
More Information
Robert Cailliau: (born 26 January 1947) is a Belgian informatics
engineer and computer scientist. Cailliau helped Tim Berners-Lee develop the World Wide Web and organized the first International World Wide Web Conference at CERN in 1994.
DynaText is an SGML publishing tool. It was introduced in 1990, and
was the first system to handle arbitrarily large SGML documents, and to render
them according to multiple style-sheets that could be switched at will.
HyTime (Hypermedia/Time-based Structuring Language) is a markup language that is an application of SGML. HyTime defines a set of hypertext-oriented element types that, in effect, supplement SGML and allow SGML
document authors to build hypertext and multimedia presentations in a standardized
way.HyTime is an international standard published by the ISO and IEC. The first edition was published in 1992, and the second edition was published in 1997.
Les Horribles Cernettes (French pronunciation: [le.z‿ɔʁiblə sɛʁnɛt], "The Horrible CERN Girls") was an all-female parody pop group, self-labelled "the one and only High
Energy Rock Band", founded by employees of CERN which performed at CERN
and other HEP related events. Their
musical style is often described as doo-wop. The initials of their name, LHC, are the same as
those of the Large Hadron
Collider which was later built at CERN. Their humorous songs are
freely available on their website.
Douglas Carl Engelbart (January 30, 1925 – July 2,
2013) was an American engineer and inventor, and an early computer and Internet
pioneer. He is best known for his work on founding the field of human–computer
interaction, particularly while at his Augmentation
Research Center Lab in SRI International, resulting in the
invention of the computer mouse, and the development of
hypertext, networked computers, and precursors to graphical
user interfaces. These were demonstrated at The Mother
of All Demos in 1968. Engelbart's Law, the observation that the intrinsic
rate of human performance is exponential, is named after him.
NLS, or the "oN-Line System", was a
revolutionary computer
collaboration system from the 1960s. Designed by Douglas Engelbart and implemented by
researchers at the Augmentation
Research Center (ARC) at the Stanford Research Institute (SRI), the NLS system
was the first to employ the practical use of hypertext links, the mouse, raster-scan video monitors, information organized by
relevance, screen windowing, presentation
programs, and other modern computing concepts. It was funded by
the Defense Advanced Research Projects Agency, NASA, and the U.S. Air Force.
Vannevar Bush (/væˈniːvɑːr/ van-NEE-var; March 11, 1890 –
June 28, 1974) was an American engineer, inventor and science administrator, who during World War II headed the U.S.
The memex (a portmanteau of "memory" and "index") is
the name of the hypothetical proto-hypertext system that Vannevar Bush described in his 1945 The Atlantic
Monthly article "As We May Think". Bush envisioned the memex as
a device in which individuals would compress and store all of their books,
records, and communications, "mechanized so that it may be consulted with
exceeding speed and flexibility." The memex would provide an
"enlarged intimate supplement to one's memory". The concept of the
memex influenced the development of early hypertext systems (eventually leading to the creation of the
World Wide Web) and personal
knowledge base software. The hypothetical implementation depicted by
Bush for the purpose of concrete illustration was based upon a document
bookmark list of static microfilm pages, and lacked a
true hypertext system where parts of pages would have internal structure beyond
the common textual format, so it's fair to say that early electronic hypertext
systems were inspired by memex rather than modeled directly upon it.
ViolaWWW is a discontinued browser, the first to be popular for the World Wide Web (WWW). It was first released in
1991/1992 for Unix and acted as the recommended browser at CERN, where the WWW was invented, but eventually lost
its position as most frequently used browser to Mosaic.
Brendan Eich (/ˈaɪk/; born 1961) is an
American technologist and creator of the JavaScript programming
language. He co-founded the Mozilla project, the Mozilla
Foundation and the Mozilla
Corporation, and served as the Mozilla Corporation's chief technical
officer and briefly its chief
executive officer. He is the CEO of Brave Software.
Ecma International is an international private
(membership-based) non-profit standards
organization for information and communication systems. It acquired
its current name in 1994, when the European Computer Manufacturers Association
(ECMA) changed its name to reflect the organization's global reach and
activities. As a consequence, the name is no longer considered an acronym and no longer uses full capitalization.
Quality of service (QoS) is the overall performance of a telephony or computer network, particularly the
performance seen by the users of the network.To quantitatively measure quality of service, several related aspects of the network service are often considered, such as error rates, bit rate, throughput, transmission delay, availability, jitter, etc.
Finjan is a company which owns the patented technology
used in many enterprise web security solutions, including real-time and
behavior-based malware prevention. The original hardware and software divisions
of Finjan were acquired by M86 Security in 2009.[1] Finjan continues to hold patents for various Web
security technologies and licenses these patents to Trustwave (formerly M86) among others. The company has
headquarters in New York and in Menlo Park, California
No comments: