ABI (Application Binary Interface)
The system environment that an executing program sees at runtime.
It is the format of an executable file,
the operating-system specifics such as process address space,
and hardware details such as
the number, sizes and reserved uses of registers.
A technology created by Adobe Systems that allows complex formatted documents
created on one computer system to be read and printed on other different
systems with the original fonts, formatting and graphic elements intact.
Different packages within the Adobe Acrobat software family are used to
create, convert, read, view and print
PDF file versions of a document. PDF files
available via the Internet are transported whole for
downloading whole before being opened to read separately.
API (Application Programmer Interface)
What the programmer sees and uses when writing source code.
It consists of the names of the library calls, and the number and types
of arguments they take.
ASCII (American Standard Code for Information Interchange)
Simple text-code. ASCII is the universal 7-bit character set
representing each of 128 characters including A-Z, a-z and 0-9.
Unlike binary, ASCII text can be displayed on any
computer on the Internet, albeit unformatted.
HTML tags are added to the text in order to achieve
visibly formatted Internet pages.
Some of the 128 ASCII characters are special characters (called control
characters) used for communications control. For example ASCII §99
shows as a "c", while ASCII §13 is the universal "carriage-return"
character which is ignored by browsers.
A property that further defines an HTML tag.
For example, in the TABLE tag
"<TABLE WIDTH="100%" ALIGN=" center">"
the optional attributes WIDTH and ALIGN specify exact settings for the
particular table required.
AVI (Audio/Visual Interleave)
- Microsoft's compressed audio/video file format.
Any high-speed communications link connecting major
ISPs together across the world. Large companies may also
have a high-speed backbone connecting many network
- Literally, binary files are files formatted as collections of 0's and 1's.
Typically the term "binary file" means the file is formatted so that it
can only be read properly by certain software applications and must be
encoded before it can be transferred across the Internet correctly.
Images are binary files, and thus a text-reader such as "Notepad" will only
display a GIF-file as a series of 0's and 1's while a
browser will display it as an image.
The range of transmission frequencies that a network can use. The greater
the bandwidth, the greater the amount of data that that can travel on the
network at one time.
- A computer software program (residing on a client's computer system)
capable of displaying an
HTML document, and enabling navigation between linked
pages. There are several browsers available, of which MOSAIC, NETSCAPE
and MS-IE are probably the best-known.
The basic unit for transferring/storing data in a computer. A byte is made
up of 8 bits (binary digits) representing a total decimal value of 0-255,
and is normally used to store one readable text character or digit.
A client is any computer remotely connected to and serviced by a host
computer. The term is also used to describe a program such as
browser that connects to and accesses data from a host
CGI (Common Gateway Interface)
- The Web's international standard for client-server application
interfacing. CGI programs (or "scripts") are written in languages such as
PERL, and perform many general Web functions.
IMAGEMAP, which handles server-side imagemaps for many
servers, is probably the most familiar. HTML forms typically require
associated CGI scripts to do something with the information submitted by
readers. CGI scripts serve as the interface between a Web server and other
computer applications, such as database managers and order processing
DNS (Domain Name System)
The Internet addressing system that connects a text-based
domain name to a specified numeric IP address.
Different servers have different IP addresses indexed
on separate DNS servers devoted exclusively to that purpose.
DNS enables a domain name to be portable (ie. remaining the same whenever
moved to a new IPP server location, where its actual
numeric IP address will have become necessarily changed).
A registered Internet name address consisting of a regional domain
(eg. ".co.uk") preceded by the name of an individual, company or
organisation (thus for example "microsoft.com").
E-MAIL (Electronic Mail)
FTP (File Transport Protocol)
- The set of common rules used to transfer files of various descriptions
servers and user-pcs. Actual FTP software varies greatly:
some packages only enable downloading from sites, while more advanced
programs allow both downloading from and uploading to servers.
GIF (Graphic Interchange Format)
- A graphics file format first originated by CompuServe.
HTTP (HyperText Transport Protocol)
- The set of common rules and regulations that
servers and browsers
must follow in "talking to each other". It is the protocol that enables the
transfer of hypertext-linked files and data.
HTML (HyperText Markup Language)
- The grammar and syntax of markup tags that, when inserted into a
document, instruct a browser
on how to present the document. HTML is a particular form of
SGML that has the added advantage of allowing
- Hypertext is any text that is not constrained to being linear (ie.
read line-by-line). Instead of a set sequence of pages (as with for example
a book), hypertext is any two or more sections of text information organised
into an interconnected web for linked readability in any order.
An international network of communication-links provided by the physical
hardware of various communities and institutions on an informal basis.
Looked at another way, it is a cooperative community of people using
computer networks to exchange information.
Started in 1969 as ARPANET (a U.S. Dept.of Defence experiment to see if
university and military research computers could be linked in a way that
would survive a nuclear attack). The design called for a network without
heirarchy or centre, each computer on the network being the equal of any
other. More and more institutions joined their own networks to it in the
1970s and started using it for their own purposes, such as exchanging
and hosting sci-fi discussion groups, until in the 1980s the military
handed the Government's hardware over to the National Science Foundation
and withdrew to start another network of their own.
The NSF hardware is now in private hands, and is just one among thousands
of new Internet service-providers. To this day, no one owns or runs the
Internet. A design that permitted no centres of authority has now, with
the help of the
World Wide Web, become the largest functioning
anarchy in the world.
Any private (ie. internal) network of company computers set up to
intercommunicate by using Internet tools such as browsers
and HTTP servers.
An Intranet is a form of
LAN that provides similar functions to the
Internet (such as electronic mail and shared newsgroup
facilities), but without having the associated security risks of linking
the company to a public network.
WINDOWS-NT is perhaps the best-known example of Intranet software.
IPP (Internet Presence Provider)
An IPP provides server webspace (measured in MegaBytes)
for clients requiring hosting facilities for website articles. Typically
a company organisation controlling several linked servers, an IPP in effect
provides the storage facilities for the data that is a website page, while
an ISP provides Internet access to it.
ISDN (Integrated Services Digital Network)
A telecomunnications system that allows digital signals to be transmitted
over a special telephone line using a specific type of
modem called an ISDN adaptor. ISDN connects a user to an
ISP much more quickly, and transmits data at 64Kbps -
between two and four times faster than a normal modem - but does not cost
as much as a leased-line.
Some ISPs do not support ISDN links.
ISP (Internet Service Provider)
An ISP provides telecommunications access to the Internet. Typically
company organisations, ISPs are also referred to as access-providers.
They enable clients to connect to websites hosted by IPPs.
- Java is an object-oriented programming language designed for fast
execution and type safety. Type safety means, for instance, that you can't
cast a Java integer into an object reference or access private memory by
corrupting Java bytecodes. Java's object-oriented model means that programs
consist exclusively of classes and their methods. Java's class inheritance
and strong typing generally require tightly coupled object hierarchies.
These requirements make Java programming more complex than
statements embedded in an HTML page.
does not have Java's static typing and strong type checking.
control-flow constructs. In contrast to Java's compile-time system
system based on a small number of data types representing
instance-based object model that still provides significant
declarative requirements. Functions can be properties of objects,
executing as loosely typed methods.
JPG/JPEG (Joint Picture Expert Group)
- A type of compressed image named after the working group that developed
it. The defined compression scheme reduces the size of an image file by up
to 20 times.
LAN (Local Area Network)
- A group of computers and other devices that are in close proximity
(such as in a business office), and are permanently connected together so
that data can pass between them.
An Intranet is an advanced form of LAN that uses
Internet tools to inter-communicate.
A telecommunications line (usually digital) that is leased from
an ISP or a telecommunications company.
Leased lines handle more bandwidth than
ISDN lines, and are rented on a monthly or annual
basis rather than charged at a measured rate.
They are a more economical option for businesses connecting several
users to the Internet or having to maintain connections for long periods
MIME (Multipurpose Internet Mail Extension)
An electronic mail protocol that allows users to attach binary files to
e-mail messages. Most mail packages support the MIME protocol.
A device enabling a computer to send/receive information over a normal
telephone line. The term modem stands for "modulator-demodulator",
describing the way in which digital computer data is converted into analog
sounds capable of transmission by telephone for reconversion by a receiving
modem at the other end. Modem speeds are measured in bits per second (bps).
PDF (Portable Document Format)
- A format that gives a portable file version of any complex formatted
document, created with
Adobe Acrobat (or converted using Acrobat Exchange).
PDF files allow people to share documents while using different platforms,
and can be easily viewed by using Acrobat Reader (a software program
distributed for free by Adobe).
PDF files available via the Internet are transported
whole for downloading before being opened to read separately.
POP3 (Post Office Protocol version 3)
- The mail protocol used by browsers and most mail
applications to retrieve mail from an
PPP (Point to Point Protocol)
- A protocol that allows a computer to use the TCP/IP
protocols and be directly connected to the Internet using a standard voice
telephone line and a high-speed modem. PPP replaced SLIP.
A device enabling permanent connection between a server and the Internet
via a leased line. You do not need to install a router
for an ISDN or modem based connection.
- A continuously available software program running on a remote computer
that provides whatever Web pages are requested by a
browser. Most (but not all) Web servers are run on
UNIX machines with high-speed connections to the
SGML (Standard Generalised Markup Language)
- Originated as GML at IBM in the late 1960s as an attempt to solve
some of the problems of transporting documents across different computer
systems. Adopted as SGML by the ISO (Geneva) 1986.
is a type of SGML DTD (or Standard GML Document Type Definition) developed
for browser based Internet use.
SMTP (Simple Mail Transfer Protocol)
- The standard Internet protocol for distributing e-mail.
TCP/IP (Transmission Control Protocol and Internet Protocol)
- The suite of networking protocol standards formulated to let disparate
types of computer communicate with each other. A protocol is a specification
describing the rules and procedures that must be followed for computers to
operate, and most Internet tools are named after the
protocols they use (eg. TCP/IP and FTP).
TCP/IP is the basic protocol "language" of the Internet,
enabling any two computers using it to "speak" to each other at the same
Three particular TCP/IP applications
- electronic mail, remote login, and file transfer
- are the Internet equivalent of the "big three" tools (hammer, screwdriver
and spanner) in a toolbox.
URL (Uniform Resource Locator)
The term for each unique address of practically every file and resource
on the Internet. Web pages are linked together by
anchored HREFs ( or Hypertext REFerences),
and the value of each HREF attribute is a URL.
URLs can be either absolute or relative. An absolute URL is a complete
(such as "http://www.domain.ext/directory/index.htm") that can also be
expressed publicly, while a relative URL has only a partial address stating
a path to another page located nearby
(ie. "directory2/home.htm"). In its simplest format, where both the
start and destination of a link are within the same file, the URL
is a name preceded by a hash or gate(#) sign
(ie. "<A HREF="#hyp">").
A term used to describe the interlinked collection of "living" (ie.
changeable) documents available on the
for the purposes of information-exchange, and composed of formatted text,
images and sound. See also the
World Wide Web
(a facility from which the looser term "Web" has become derived).
There are 3 ways one can browse the Web: In TTY or linemode, through
a commercial online service provider, or as an Internet host.
WWW (The World Wide Web)
- Also called W3. The first and foremost of various information discovery and retrieval
applications (others include Archie, Gopher, WAIS and Mosaic). The WWW
began in 1989 when Tim Berners-Lee and Robert Cailliau submitted a proposal
to their colleagues at CERN for a client-server based hypermedia system.
The applications use a web of linked nodes with one node designated as
home - the home page for a Web server. See also
WYSIWYG (What You See Is What You Get)
- An acronym.
WYSIWYG is generally regarded as an impossibility with HTML
documents due to every web designers's lack of control over any viewer's
browser type and version, installed system fonts and
preferred screen resolution setting!