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Packet/Packet Switching: A packet is a chunk of information sent over a network.
Packet-switching is the process by which a carrier breaks up data into these chunks or
"packets." Each packet contains the address of origin, the address of its
destination, and information about how to reunite with other related packets. This process
allows packets from many different locations to co-mingle on the same lines and be sorted
and directed to different routes by special machines along the way.
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Page view: Like an ad view but for an individual Web page. A page view occurs
each time a Web page is requested from a server.
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Pathname: A pathname indicates the location of a particular file or directory by
outlining the route or "path" from the host name (if the file resides on a
remote server) through the directory structure to the desired filename or directory name.
Each name in the series of names that define a path are separated by a slash. If the file
is located in the current working directory on your computer, it is referred to only by
its filename.
Pathnames can be absolute or relative. An absolute pathname provides the full path
(address) of a file, including the computer system, directories, and subdirectories (if
any) it resides in. Relative pathnames are used to describe a file or directory location
on the user's system relative to the user's current location on the system (i.e. based on
which level of the directory structure the user is in).
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PERL (Practical Extraction and Reporting Language): A robust programming
language frequently used for creating CGI programs on web servers because it is faster
than UNIX shell script programs, it can read and write binary files, and it can process
very large files. The major advantage of PERL over C as a programming language is that
PERL does not need to be compiled.
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Pixel: A pixel (short for picture element) is the smallest element that can be
displayed on a video screen or computer monitor, and is often used as a unit of
measurement for image size and resolution. The number of pixels (width and height) in an
image defines its size and the number of pixels in an inch defines the resolution of the
image.
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Plug-in: A plug-in extends the capabilities of a web browser, such as Netscape
Navigator or Microsoft Explorer, allowing the browser to run multimedia files. The term
"plug-in" is used in two ways on the Internet. The technical definition of a
plug-in is a small add-on piece of software that conforms to Netscape Navigator standard.
Other browsers however, including Microsoft Explorer, support many Netscape plug-ins. But
Explorer actually uses a different software standard, called an ActiveX control, instead
of plug-ins.
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PPP: PPP (Point-to-Point Protocol) is a communications protocol used to transmit
network data over telephone lines. It allows you to connect your computer to the Internet
itself, rather than logging on through an Internet Service Provider's host computer and
using UNIX commands through a shell. This type of connection lets you communicate directly
with other computers on the network using TCP/IP connections. It is part of the TCP/IP
suite of programs necessary to connect to and use the Internet.
If you have a dial-up account with an Internet service provider, you are using either
PPP or SLIP to make your connection to the Internet. PPP (Point-to-Point Protocol) is
rapidly replacing SLIP (Serial Line Internet Protocol) as the more common standard. Where
as SLIP is easy to install and to use, it does not provide error correction or certain
negotiation features that are built into PPP.
Where do you get PPP? If you bought an Internet package, a PPP program would be part of
the collection of software programs you received. Some Internet Service Providers will
give you a disk with the appropriate software when you sign up for an account. Others will
point you to a BBS where you can download the software yourself.
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Rich-media ads: HTML or JavaScript banner ads that may offer multiple functions,
such as pull-down menus or search fields.
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Robots: Programs that are designed to automatically go out and explore the
Internet for a variety of purposes. Robots that record and index all of the contents of
the network to create searchable databases are sometimes called Spiders or Worms.
WebCrawler and Lycos are popular examples of this.
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Shockwave: Shockwave is a set of programs that allow Macromedia Director
animation files to be played over the Internet with a web browser. Possible uses for this
type of animation on the Web include online advertising, games, training, and animated
logos.
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Signature: Text automatically included at the bottom of an e-mail message or
newsgroup posting to personalize it. This can be anything from a clever quote to some
additional information about the sender, like their title, company name and additional
e-mail addresses they may have. Netiquette suggests that signatures be four lines or
fewer.
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Site traffic: An ambiguous term. Some consider the number of unique visitors
during a given period to be a site's traffic. Others consider it the number of page views
during a given period (usually a month).
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SLIP: An acronym for Serial Line Internet Protocol. SLIP is a communications
protocol that, like PPP, allows you to connect your computer to the Internet itself, using
a telephone line. It is part of the TCP/IP suite of programs necessary to connect to and
use the Internet.
If you have a dial-up account to an Internet service provider, you are using either PPP
or SLIP to make your connection to the Internet. Although SLIP is easy to install and use,
it does not provide the error correction or negotiation features that PPP has. For this
reason, PPP is rapidly replacing SLIP as the more common Standard.
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SPAM: Originally just a canned sandwich filler product, now this term is also
used to refer to the practice of blindly posting commercial messages or advertisements to
a large number of unrelated and uninterested newsgroups.
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Secure Socket Layer (SSL): A protocol developed by Netscape Communications
Corporation for securing data transmission in commercial transactions on the Internet.
Using public-key cryptography, SSL provides server authentication, data encryption, and
data integrity for client/server communications.
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T-1 Line: A high-speed digital connection capable of transmitting data at a rate
of approximately 1.5 million bits per second. A T1 line is typically used by small and
medium-sized companies with heavy network traffic. It is large enough to send and receive
very large text files, graphics, sounds, and databases instantaneously, and is the fastest
speed commonly used to connect networks to the Internet. Sometimes referred to as a leased
line, a T1 is basically too large and too expensive for individual home use.
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T-3 Line: A super high-speed connection capable of transmitting data at a rate
of 45 million bits per second. This represents a bandwidth equal to about 672 regular
voice-grade telephone lines, which is wide enough to transmit full-motion real-time video,
and very large databases over a busy network. A T3 line is typically installed as a major
networking artery for large corporations and universities with high volume network
traffic. For example, the backbones of the major Internet service providers are comprised
of T3 lines.
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TCP/IP: Stands for Transmission Control Protocol/Internet Protocol. This is the
language governing communications between all computers on the Internet. TCP/IP is a set
of instructions that dictates how packets of information are sent across multiple
networks. Also included is a built-in error-checking capability to ensure that data
packets arrive at their final destination in the proper order.
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IP, or Internet Protocol, is the specification that determines where packets are routed
to, based on their destination address. TCP, or Transmission Control Protocol, makes sure
that the packets arrive correctly at their destination address. If TCP determines that a
packet was not received, it will try to resend the packet until it is received properly.
Telnet: A software program that allows you to log in to other remote computers
on the Internet to which you have access. Once you are logged into the remote system, you
can download files, engage in conferencing, and perform the same commands as if you were
directly connected by computer. You need an Internet account to be able to use a telnet
program.
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Unique users: The number of different users who access a Web site or page during
a given period. To measure this, Web sites often employ a user registration system.
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UNIX: UNIX is the trademarked name of the multi-user, multi-tasking,
time-sharing operating system developed at AT&Tās Bell Labs in 1969. Many web sites
are maintained on UNIX systems. While technically the name UNIX refers to only a few
trademark-licensed versions, it is often used to refer to the many versions currently
available on the market. The differences to the user are slight.
UNIX was originally designed on a "spare" minicomputer, to allow some folks
to have a quick time-sharing system to simplify their documentation procedures. The
moniker UNIX was given to it by the somewhat sarcastic users of the huge mainframes
prevalent in those days -- pointing out that they considered it to be a somewhat
underpowered operating system.
AT&T commercially released UNIX in the early 1970ās. By the late '70s, the
University of California, Berkeley had developed its own version, called BSD (for Berkeley
Software Distribution), which it offered for free to other colleges and universities
Because it could run on many different computer platforms, it quickly became the
platform of choice for many researchers and students. Since networking and e-mail are both
integral to UNIX, it was easy for two or more UNIX computers to "talk" to each
other. That is why by the late 1980ās, UNIX ran on almost every machine on the Internet.
In fact, the Internet's protocols were developed on UNIX machines, for UNIX machines. For
example, Usenet, the loose confederation of computers that exchanges newsgroups and
electronic mail by passing messages back and forth, was based almost exclusively on UNIX
machines.
UNIX now runs on every hardware platform from PC and Macintosh to high- performance
graphical workstations to multimillion dollar supercomputers. The big difference between
versions and platforms is that the more expensive platforms run faster or support more
simultaneous users.
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URL (Uniform Resource Locator): An acronym for Uniform Resource Locator. URL is
the address for a resource or site (usually a directory or file) on the World Wide Web and
the convention that web browsers use for locating files and other remote services.
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Usenet: Usenet refers to the collection of newsgroups (sometimes called the Big
Eight hierarchies) and a set of agreed-upon rules for distributing and maintaining them.
More than 13,000 newsgroups exist around the world and the majority of them are a part of
Usenet. However, a fairly large number of alternative newsgroups have emerged outside of
Usenet.
Usenet newsgroups are arranged hierarchically first by the name of the group, followed
by the name of the subgroups. Each name in the hierarchy is separated by a period. For
example, the discussion group about rose gardening is rec.gardens.roses. This means the
conversation is in the general grouping of rec. (which stands for recreation), and a
subgroup of recreation called gardens. In this particular case, an additional subgroup of
gardens has been created for roses. Each additional subgroup in a hierarchy defines how
narrow or specialized the discussion topic is. It's not uncommon to find newsgroups with
several subgroups.
The Usenet Big Eight hierarchies are:
comp - computer science and related topics
news - information about the newsgroups
rec - hobbies and recreational activities
sci - scientific research and applications
soc - social issues, including politics
talk - debate on controversial topics
misc - anything that doesn't fit in the above categories
Not all newsgroups are part of Usenet. For example, the newsgroups with a prefix of
alt. are not part of the core Usenet newsgroups, although they may look just like Usenet
newsgroups to the average user. Another example of a non-Usenet newsgroup is the Clarinet
news feed, which is a commercial information service that also looks like any other
newsgroup to the end-user.
System administrators decide which newsgroups will be carried on their systems. Making
newsgroups available to their users means dedicating hard-drive space for storage, so
decisions have to be made about the allocation of those resources. Many administrators
will not carry the "alt." groups. Some even refuse to carry any group with the
word "sex" in the name. You have to check with your provider to find out what
newsgroups they carry.
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Visitor: An individual who interacts with a Web site. Several methods are being
used to identify visitors.
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Visits: A series of page requests by a visitor on a given site within a
specified period, usually 30 minutes. Visits usually break down into the number of pages
requested per visit per unique user. That way you know who visits your site, how often
they come and how long they stay.
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VRML (Virtual Reality Modeling Language): VRML is an open, platform-independent
file format for 3-D graphics on the Web. It encodes computer-generated graphics in a way
that makes them easily transported across the network. VRML requires a special web browser
to display these graphics which simulate virtual reality 3-D "environments" or
"worlds" through which the user can move and interact with objects. These 3-D
"worlds" can contain objects that link to documents, other objects, or other 3-D
worlds.
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Webmaster: A person in charge of maintaining a web site. This can include
writing HTML files, setting up more complex programs, and responding to e-mail. Many sites
encourage you to mail comments and questions about the site's web pages to the web master.
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Web Page: A web page is a document created with HTML (HyperText Markup Language)
that is part of a group of hypertext documents or resources available on the World Wide
Web. Collectively, these documents and resources form what is known as a web site.
You can read HTML documents that reside somewhere on the Internet or on your local hard
drive with a piece of software called a web browser. Web browsers read HTML documents and
display them as formatted presentations, with any associated graphics, sound, and video,
on a computer screen.
Web pages can contain hypertext links to other places within the same document, to
other documents at the same web site, or to documents at other web sites. They also can
contain fill-in forms, photos, large clickable images (image maps), sounds, and videos for
downloading.
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Web Site: The collection of network services, primarily HTML documents, that are
linked together and that exist on the Web at a particular server. Exploring a web site
usually begins with the home page, which may lead you to more information about that site.
A single server may support multiple web sites.
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World Wide Web: The exact definition for the World Wide Web (popularly known as
the Web) varies, depending on whom you ask. Three common descriptions are:
- A collection of resources (Gopher, FTP, http, telnet, Usenet, WAIS and others) which can
be accessed via a web browser.
- A collection of hypertext files available on web servers.
- A set of specifications (protocols) that allows the transmission of web pages over the
Internet.
You can think of the Web as a worldwide collection of text and multimedia files and
other network services interconnected via a system of hypertext documents. HTTP (HyperText
Transfer Protocol) was created in 1990, at CERN, the European Particle Physics Laboratory
in Geneva, Switzerland, as a means for sharing scientific data internationally, instantly,
and inexpensively. With hypertext a word or phrase can contain a link to other text. To
achieve this they developed a programming language called HTML, that allows you to easily
link you to other pages or network services on the Web.
If you encounter a page with a word that is highlighted in some way (usually in a
different color and underlined), you can click on that word and "go to" the page
or resource to which connects. Of course, you are not actually "going" anywhere
when you do this, but rather, you are summoning the file or resource that the link points
to. This non-linear, non-hierarchical method of accessing information was a breakthrough
in information sharing and quickly became the major source of traffic on the Internet.
The basic elements of the World Wide Web are:
- HTTP (Hypertext Transfer Protocol) - the set of standards used by computers to
communicate and share files with each other.
- URL's (Uniform Resource Locator) - the "address" of a resource (file or
diretory) on the Web.
- HTML (Hypertext Markup Language) - the programming "tags" added to text
documents that turn them into hypertext documents.
The World Wide Web Consortium at CERN continues to be the premier source of information
about the Web. For more background information link to the history of CERN involvement in
the Web and the Internet.
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