A small Java application that is downloaded by an ActiveX or Java-enabled web browser. Once it has been downloaded, the applet will run on the user's computer. Common applets include financial calculators
and web drawing programs.
The capacity of a networked connection. Bandwidth determines how much data can be sent along the networked wires.
Bandwidth is particularly important for Internet connections, since greater bandwidth also means faster downloads.
Most computers use combinations of eight bits, called bytes, to represent one character of data or instructions.
For example, the word “cat” has three characters, and it would be represented by three bytes.
A small data-memory storage area that a computer can use to instantly re-access data instead of re-reading the
data from the original source, such as a hard drive. Browsers use a cache to store web pages so that the user may view them again without reconnecting to the Web.
Computer Aided Drawing-Computer Aided Manufacturing. The instructions stored in a computer that will be translated
to very precise operating instructions to a robot, such as for assembling cars or laser-cutting signage.
Compact Disc Read-Only Memory. An optically read disc designed to hold information such as music, reference
materials, or computer software. A single CD-ROM can hold around 640 megabytes of data, enough for several encyclopedias. Most software programs are now delivered on CD-ROMs.
Common Gateway Interface. A programming standard that allows visitors to fill out form fields on a Web page and have that information interact with a database, possibly coming back to the user as another Web page.
CGI may also refer to Computer-Generated Imaging, the process in which sophisticated computer programs create
still and animated graphics, such as special effects for movies.
A single user of a network application that is operated from a server. A client/server architecture allows many people to use the same data simultaneously. The
program's main component (the data) resides on a centralized server, with smaller components (user interface) on each client.
The main directory of the user interface. Desktops usually contain icons that represent links to the hard drive, a network (if there is one), and a trash or recycling can for files to be deleted. It can also display icons of frequently
used applications, as requested by the user.
Two distinct types. The names refer to the media inside the container:
A hard disc stores vast amounts of data. It is usually inside the computer but can be a separate peripheral on the outside. Hard discs are made up of several rigid coated metal discs. Currently, hard discs can store 15 to 30 Gb (gigabytes)
A floppy disc, 3.5" square, usually inserted into the computer and can store about 1.4 megabytes of data. The 3.5" square “floppies” have a very thin, flexible disc inside. There is also an intermediate-sized
floppy disc, trademarked Zip discs, which can store 250 megabytes of data.
Represents an IP (Internet Protocol) address or set of IP addresses that comprise a domain. The domain name appears in URLs to identify web pages or in email addresses. For example, the email address for the First Lady is firstname.lastname@example.org, “whitehouse.gov”
being the domain name. Each domain name ends with a suffix that indicates what “top level domain” it belongs to.
These are: “.com” for commercial, “.gov” for government, “.org” for organization, “.edu”
for educational institution, “.biz” for business, “.info” for information, “.tv” for television,
“.ws” for website. Domain suffixes may also indicate the country in which the domain is registered. No two parties
can ever hold the same domain name.
Digital Subscriber Line. A method of connecting to the Internet via a phone line. A DSL connection uses copper
telephone lines but is able to relay data at much higher speeds than modems and does not interfere with telephone use.
A text-based expression of emotion created from ASCII characters that mimics a facial expression when viewed
with your head tilted to the left. Here are some examples: :-) Smiling :-( Frowning ;-) Winking :_( Crying
The process of transmitting scrambled data so that only authorized recipients can unscramble it. For instance,
encryption is used to scramble credit card information when purchases are made over the Internet.
Software created by people who are willing to give it away for the satisfaction of sharing or knowing they helped
to simplify other people's lives. It may be freestanding software, or it may add functionality to existing software.
A person with technical expertise who experiments with computer systems to determine how to develop additional
features. Hackers are occasionally requested by system administrators to try and “break into” systems via a network
to test security. The term hacker is sometimes incorrectly used interchangeably with cracker. A hacker is called a “white hat” and a cracker a “black hat.”
Hypertext Markup Language. A standard of text markup conventions used for documents on the World Wide Web. Browsers interpret the codes to give the text structure and formatting (such as bold, blue, or italic).
Hypertext Transfer Protocol. A common system used to request and send HTML documents on the World Wide Web. It is the first portion of all URL addresses on the World Wide Web (e.g., http://www.whitehouse.gov).
A system for organizing text through links, as opposed to a menu-driven hierarchy such as Gopher. Most Web pages include hypertext links to other pages at that site, or to other sites on the World Wide Web.
Symbols or illustrations appearing on the computer screen that indicate program files or other computer functions.
The interconnections that allow a device, a program, or a person to interact. Hardware interfaces are the cables that connect the device to its power source and to other devices. Software interfaces allow the
program to communicate with other programs (such as the operating system), and user interfaces allow the user to communicate with the program (e.g., via mouse, menu commands, icons, voice commands, etc.).
An international conglomeration of interconnected computer networks. Begun in the late 1960s, it was developed
in the 1970s to allow government and university researchers to share information. The Internet is not controlled by any single
group or organization. Its original focus was research and communications, but it continues to expand, offering a wide array
of resources for business and home users.
An Internet Protocol address is a unique set of numbers used to locate another computer on a network. The format
of an IP address is a 32-bit string of four numbers separated by periods. Each number can be from 0 to 255 (i.e., 220.127.116.116).
Within a closed network IP addresses may be assigned at random, however, IP addresses of web servers must be registered to avoid duplicates.
An object-oriented programming language designed specifically for programs (particularly multimedia) to be used over the Internet. Java allows programmers to create small programs or applications (applets) to enhance Web sites.
A UNIX®-like, open-sourceoperating system developed primarily by Linus Torvalds. Linux is free and runs on many platforms, including both PCs and Macintoshes. Linux is an open-source operating system, meaning that the source code of the operating
system is freely available to the public. Programmers may redistribute and modify the code, as long as they don't collect
royalties on their work or deny access to their code. Since development is not restricted to a single corporation more programmers
can debug and improve the source code faster..
. An operating system with a graphical user interface, developed by Apple® for Macintosh® computers. Current System “X.1” (10) combines
the traditional Mac interface with a strong underlying UNIX® operating system for increased performance and stability.
Temporary storage for information, including applications and documents. The information must be stored to a permanent device, such as a hard disc or CD-ROM before the power is turned off, or the information will be lost. Computer memory is measured in terms of the amount of information
it can store, commonly in megabytes or gigabytes.
The horizontal strip across the top of an application's window. Each word on the strip has a context sensitive drop-down menu containing features and actions that are available for the application in use.
An abbreviation for Megahertz, or one million hertz. One MHz represents one million clock cycles per second
and is the measure of a computer microprocessor's speed. For example, a microprocessor that runs at 300 MHz executes 300 million
cycles per second. Each instruction a computer receives takes a fixed number of clock cycles to carry out, therefore the more
cycles a computer can execute per second, the faster its programs run. Megahertz is also a unit of measure for bandwidth.
A device that connects two computers together over a telephone or cable line by converting the computer's data
into an audio signal. Modem is a contraction for the process it performs: modulate-demodulate.
A small hand-held device, similar to a trackball, used to control the position of the cursor on the video display; movements of the mouse on a desktop correspond to movements
of the cursor on the screen.
Computer programs whose original source code was revealed to the general public so that it could be developed
openly. Software licensed as open source can be freely changed or adapted to new uses, meaning that the source code of the
operating system is freely available to the public. Programmers may redistribute and modify the code, as long as they don't collect royalties
on their work or deny access to their code. Since development is not restricted to a single corporation more programmers can
debug and improve the source code faster.
A set of instructions that tell a computer on how to operate when it is turned on. It sets up a filing system
to store files and tells the computer how to display information on a video display. Most PC operating systems are DOS (disc operated system) systems, meaning the instructions are stored on a disc (as opposed to being originally stored in the
microprocessors of the computer). Other well-known operating systems include UNIX, Linux, Macintosh, and Windows.
Personal Digital Assistant. A hand-held computer that can store daily appointments, phone numbers, addresses,
and other important information. Most PDAs link to a desktop or laptop computer to download or upload information.
Portable Document Format. A format presented by Adobe Acrobat that allows documents to be shared over a variety
of operating systems. Documents can contain words and pictures and be formatted to have electronic links to other parts of the document or to
places on the web.
A mechanical device for printing a computer's output on paper. There are three major types of printers:
Dot matrix: creates individual letters, made up of a series of tiny ink dots, by punching a ribbon with
the ends of tiny wires. (This type of printer is most often used in industrial settings, such as direct mail for labeling.)
Ink jet: sprays tiny droplets of ink particles onto paper.
Laser: uses a beam of light to reproduce the image of each page using a magnetic charge that attracts
dry toner that is transferred to paper and sealed with heat.
A series of instructions written by a programmer according to a given set of rules or conventions (“syntax”).
High-level programming languages are independent of the device on which the application (or program) will eventually run; low-level languages are specific to each program or platform. Programming language instructions are converted into programs in language specific to a particular machine or operating system (“machine language”) so that the computer can interpret and carry out the instructions. Some common programming
languages are BASIC, C, C++, dBASE, FORTRAN, and Perl.
An input device, like a mouse. It has a magnifying glass with crosshairs on the front of it that allows the operator to position it precisely when tracing
a drawing for use with CAD-CAM software.
Internet tool that delivers specific information directly to a user's desktop, eliminating the need to surf for it. PointCast, which
delivers news in user-defined categories, is a popular example of this technology.
Random Access Memory. One of two basic types of memory. Portions of programs are stored in
RAM when the program is launched so that the program will run faster. Though a PC has a fixed amount of RAM, only portions
of it will be accessed by the computer at any given time. Also called memory.
Read-Only Memory. One of two basic types of memory. ROM contains only permanent information
put there by the manufacturer. Information in ROM cannot be altered, nor can the memory be dynamically allocated by the computer
or its operator.
An electronic device that uses light-sensing equipment to scan paper images such as text, photos, and illustrations
and translate the images into signals that the computer can then store, modify, or distribute.
Taking packets of information (sound or visual) from the Internet and storing it in temporary files to allow
it to play in continuous flow.
stylus and tablet
stylus and tablet
A input device similar to a mouse. The stylus is pen shaped. It is used to “draw” on a tablet (like drawing on paper) and the tablet transfers
the information to the computer. The tablet responds to pressure—the firmer the pressure used to draw, the thicker the
Universal Power Supply or Uninterruptible Power Supply. An electrical power supply that includes a battery to
provide enough power to a computer during an outage to back-up data and properly shut down.
Universal Serial Bus. An industry standard for connecting different compatible peripheral devices across multiple platforms. Devices include printers, digital cameras, scanners, game pads, joysticks, keyboards and mice, and storage devices. USB peripherals offer the use of plug-and-play convenience by eliminating the need to turn off or restart the computer when attaching a new peripheral. Users can connect
USB peripherals whenever they need them. For example, a user producing a newsletter could easily swap a digital camera for
a scanner-without any downtime. Small, simple, inexpensive, and easy to attach, USB supports simultaneous connection of up
to 127 devices by attaching peripherals through interconnected external hubs.
A multiple-socket USB connecter that allows several USB-compatible devices to be connected to a computer.
A large unmoderated and unedited bulletin board on the Internet that offers thousands of forums, called newsgroups. These range from newsgroups exchanging information on scientific advances
to celebrity fan clubs.
A technology that allows one to experience and interact with images in a simulated three-dimensional environment.
For example, you could design a room in a house on your computer and actually feel that you are walking around in it even
though it was never built. (The Holodeck in the science-fiction TV series Star Trek: Voyager would be the ultimate
virtual reality.) Current technology requires the user to wear a special helmet, viewing goggles, gloves, and other equipment
that transmits and receives information from the computer.
An unauthorized piece of computer code attached to a computer program or portions of a computer system that
secretly copies itself from one computer to another by shared discs and over telephone and cable lines. It can destroy information
stored on the computer, and in extreme cases, can destroy operability. Computers can be protected from viruses if the operator
utilizes good virus prevention software and keeps the virus definitions up to date. Most viruses are not programmed to spread
themselves. They have to be sent to another computer by e-mail, sharing, or applications. The worm is an exception, because it is programmed to replicate itself by sending copies to other computers listed in the
e-mail address book in the computer. There are many kinds of viruses, for example:
Boot viruses place some of their code in the start-up disk sector to automatically execute when booting.
Therefore, when an infected machine boots, the virus loads and runs.
File viruses attached to program files (files with the extension “.exe”). When you run the
infected program, the virus code executes.
Macro viruses copy their macros to templates and/or other application document files.
Trojan Horse is a malicious, security-breaking program that is disguised as something benign such as
a screen saver or game.
Worm launches an application that destroys information on your hard drive. It also sends a copy of the virus to everyone in the computer's e-mail address book.
A portion of a computer display used in a graphical interface that enables users to select commands by pointing
to illustrations or symbols with a mouse. “Windows” is also the name Microsoft adopted for its popular operating system.
A network of servers on the Internet that use hypertext-linked databases and files. It was developed in 1989 by Tim Berners-Lee, a British computer scientist,
and is now the primary platform of the Internet. The feature that distinguishes the Web from other Internet applications is its ability to display graphics in addition to text.
What You See Is What You Get. When using most word processors, page layout programs (See desktop publishing), and web page design programs, words and images will be displayed on the monitor as they will look on the printed page or web page.
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