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Active Application: An application which is currently running and is in the foreground. The active application is the one you are currently able to work in.

AC: Alternating Current. The electricity that comes out of wall sockets. Some devices, such as laptop and notebook computers, need to use AC adaptors.

AC Adaptor: Device which transforms AC electricity into a form that a device with special power requirements such as some laptops and notebooks can use.

Active Matrix Screen: A type of LCD screen used on portable computers, in which there is a separate circuit for each pixel, allowing each pixel to be activated completely independently. It also allows the pixels to be addressed more quickly than a passive matrix display does.

AIX: A version of UNIX produced by IBM for their RS/6000 computer systems.

Alias: In the Macintosh System 7, a tiny file which points to another file. It is not a copy of the original file but rather a link to it. When you double-click on an alias, it points to the original file and the original file is opened. Aliases are useful in organizing files without making multiple copies.

Anonymous ftp: See FTP.

ANSI: American National Standards Institute. The acronym is used to identify standards created by the institute, such as the ANSI 8-bit character set, or "ANSI_C".

Apple: A computer company, maker of the Macintosh line of computers. They also produce the Newton, and produced the Apple and Apple II computers.

AppleTalk: Communications protocol developed by Apple computers. Although fairly slow, AppleTalk is cheap to implement on Macintosh computer because the hardware for it is built into the machines. Using special adaptor boards, IBM PC and compatible machines can also be incorporated into an AppleTalk network. The AppleTalk protocol can also be run over ethernet, though it is then called EtherTalk.

Application: A program. Files such as Microsoft Word, MacWrite, MacPaint, etc. are applications. Applications give the computers instructions which provide the user with tools to accomplish a task. For instance, a word processing application provides space to type in, means to format the text, a spelling checker, etc.

Application Icon: In Windows. A graphic that represents a running application. This icon appears only after you start an application and then minimize it.

Architecture: The structure and organization of a computer's hardware, or system software, including items such as the CPU type, bus type, etc.

Arrow Keys: Also called Direction Keys. Keys used at times to navigate around the screen- especially in text areas. Arrow keys have arrows pointing up, down, right, and left.

ASCII: American Standard Code for Information Interchange. The American Standard Code for Information Interchange 7-bit character set. It consists of the first 128 (0-127) characters of the ANSI character set (and most other 8-bit character sets). The ASCII character set is the most universal character-coding set.

ASCII text file: A File that contains nothing but ASCII characters without special formatting. ASCII text files are sometimes used in file transfers.

AT: Any IBM or compatible computer that contains an 80286 processor and 16-bit bus.

Autoconfig: Automatic configuration. The ability of computer hardware to detect the presence of expansion devices, and, using information resident in those devices, configure the system to run the device properly.

AUTOEXEC.BAT: A batch program (set of commands) that is automatically carried out by MS-DOS whenever the computer is started or restarted. The file contains basic startup commands that help configure the system. Often, when a computer stops doing what it normally does when it boots (enters dos shell automatically or starts Windows, etc.), it is because the autoexec.bat file has been deleted. It is a good idea to have a copy of the autoexec.bat file (printed or on a separate disk) in case this happens.

A/UX: Apple's version of UNIX which ran on Macintosh computers. Continued support for A/UX is up in the air.

Backbone: A network that connects other networks. For instance, there is a campus backbone at the U of C that connects the networks of different departments and buildings together.

Background: 1) The area behind and outside the active window, including the desktop and any other application windows or icons. 2) Applications can run in the "background". These applications are still running but they are not those in the active window and run without user intervention.

Backup: Creating extra copies of files in case the original copies are damaged or destroyed. It has been said that you should have at least three copies of important files- one on your hard disk, one on a floppy, and another on any media stored off-site in a fire-proof safe. That may be a little paranoid but consider what would happen if you lost particular files. Let that dictate how many backups you have and how carefully they are stored and updated.

BASIC: Beginners All-Purpose Symbolic Instruction Code. An easy to learn and hence once popular programming language. BASIC is not as commonly used today.

Batch file/program: An ASCII text file which contains a list of DOS commands and program names. When the batch file is run, the commands and programs are run in sequence just as if you had typed them at the MS-DOS prompt. Batch files are distinguished by their ".BAT" suffix.

Baud Rate: Speed at which information is transferred. Generally referred to as bps now.

BBS: See Bulletin Board System.

Benchmark: Test of performance of a computer or peripheral device. While benchmarks can offer seemingly objective tests of performance, the best test is to use the computer or peripheral with the applications and files you will actually be using.

Beta: A conventional designation of pre-release software. A beta version of software is usually in secondary testing (alpha versions are earlier releases), and is sometimes publically available, but sometimes only available to particular users (beta testers). Beta software is usually somewhat unstable, and may have more bugs than a regular release.

Binary file: A file containing information that is in machine-readable form; it can be read only by an application. "Binary_file" usually refers to a file that uses all 8 bits of each byte for information. Text files usually use only 7 bits, leaving the 8th bit as 0.

Binary transfer: Method of transferring files to or from a remote computer in which all eight bits of each byte are transferred. In a text transfer, the eighth bit is ignored.

Binhex: A file format for encoding Macintosh binary files as text files, for easier transfer between computers. Binhex files usually have the suffix ".hqx" Almost all Macintosh communication programs will automatically detect and translate files in Binhex format.

BIOS: Basic In/Out System. Part of an IBM or compatible computer than manages the flow of signals through the bus.

Bit: Binary digit. Smallest unit of digital information, either on or Off, 1 or 0.

Bitmap: An image stored as a pattern of dots (or pixels).

Boolean logic: Rules and concepts for comparing data conditions including LESS THAN, GREATER THAN, EQUAL TO, AND, OR, or NOT. Used often to specify the conditions of a search on a large set of data.

Boot: The loading of the operating system and starting of initial processes into a computer. From the saying, "pulling_oneself_up_by one's_bootstraps."

bps: Bits Per Second. Speed at which data is transferred. Often used in discussing the speed of modems and serial transmissions.

Bridges: filters traffic within a single network. They operate like a traffic cop to direct messages toward a destination and to exclude messages that are intended for other destinations. Like repeaters, they can join network segments. Unlike repeaters, they can extend the network by resending the signal. You may find you need a bridge as traffic on your network increases.

Browse: In Windows. To look through files and directories. Some dialog boxes have a Browse button, which opens another dialog box that lists files and directories so that you can easily select the file you want.

Buffer: A temporary storage place for information.

Bulletin Board System (BBS): Electronic bulletin boards are computers running with software which allows callers to leave messages and access information much like an actual bulletin board. Most bbs's are accessed via modem although some, like the CCS bbs, can also be accessed through a network. Services that a bbs can offer are electronic mail, conferences on topics of interest, and collections of documents (text files, pictures, and sounds). BBS's are often good sources for software, especially shareware and freeware utilities.

Bus: Part of a chip or circuit board designed to send and receive data. The bus on a computer's motherboard contains slots for expansion cards.

Byte: The amount of memory needed to specify one ASCII character; eight bits. Kilobytes (1000 bytes) and Megabytes (1,000,000 bytes) are usually used in discussing the amount of memory a computer uses.

C: A programming language that has become very popular with programmers.

C++: An extension of the C programming language.

Cache: RAM memory set aside as a buffer between the CPU and either a hard disk or slower RAM. Because a cache can be accessed quickly, it speeds up general data flow.

Card: A hardware expansion unit which is installed inside the case of a computer, into an expansion slot on the motherboard.

Cartridge Font: See font cartridge.

Cascade: In Windows. A way of arranging open windows on the desktop so that they overlap each other, with the title bar of each window remaining visible.

Cascading menu: Also called a hierarchical menu or submenu. A menu that opens from a command on another menu. In Windows, a command that opens a cascading menu has a right arrow next to it.

CCITT: Comite Consultatif Internationale de Telegraphique et Telephonique. An international comminittee which sets communications standards. The V.32, V.32bis, V.42, etc standards for modem speed and compression are CCITT standards. CCITT has been replaced by the ITU.

CD-ROM: Compact Disk-Read Only Memory. Compact Disks which contain programs or data which cannot be written to. Large files of ClipArt and large applications are examples of files which are distributed on CD-ROM because they very large. CD-ROMs can hold over 600 MB of data.

Centronics interface (cable): See Parallel Interface.

Character set: A group of letters, numbers, and symbols that have some relationship in common. For example, the ASCII character set contains characters that make up the ASCII coding scheme.

Check box: Found in graphical user interfaces (GUIs). A small square box that appears in a dialog box and that can be selected or cleared. When the check box is selected, an X appears in the box (alternately, it can be darkened, or identified as selected in another way). A check box represents an option that you can turn on and off.

Chooser: On Macintoshes, the facility that controls the selecting of printers, file servers, and other networked devices.

CHRP: Common Hardware Reference Platform: See PowerPC Platform.

CISC: Complex Instruction Set Computing. A CPU architecture in which a large number of instructions are hard coded into the chip. Most older CPUs are CISC chips, like the Motorola 680x0, the Intel 80x86, etc. The Pentium chips have some RISC like features, but are still basically CISC chips. Contrast with RISC.

Claris: A software company owned by Apple which markets Apple's software while Apple Corporation officially markets only hardware. Claris also produces Windows software. Some Claris products are Claris Works, Claris Draw, and FileMaker Pro.

CLI: See Command Line Interface.

Client: A computer using services or resources provided by a remote machine, called a server. Often, communications software will have a separate version for the client, or guest, and the server, or host.

ClipArt: Images that are available for use on computers. Companies have begun to sell collections of ClipArt that may be useful in business, etc. documents.

Clipboard: A temporary storage location used to transfer data between documents and between applications. Typically, you transfer data to the Clipboard by using an application's Copy or Cut command, and you insert data from the Clipboard by using the applications's Paste command. In Windows, you use the Clipboard Viewer to view the contents of the Clipboard. On the Macintosh, you choose Show Clipboard from the edit or window menu of most applications.

Close Box: On the Macintosh, small square in the upper-left hand corner of a window that allows you to Close that window.

Cluster: A group of sectors on a disk. DOS allocates disk space to files in clusters.

CMOS: Complementary Metal Oxide Semiconductor. A small section of RAM used to hold certain hardware configuration parameters in IBM and compatible computers.

Coaxial cable: A type of cable that is commonly used due to its insensitivity to noise interference. Coaxial cable is often used in Ethernet networks; both thick (10Base5) and thin (10Base2) ethernet cables are coaxial.

COBOL: Common Business-Oriented Language. A programming language that is used for business programs.

COM Port: Also called a serial port. A connection on an IBM or compatible computer, usually named COM1, where you plug in the cable for a serial device. Common serial devices are printers and modems. Serial ports are smaller than parallel ports and usually contain 9 pins.

Command Key: A key found on the keyboards of some computers which often modifies the action performed when pressing another key in combination with it. On a Macintosh, the command key is marked with the Mac Apple symbol and a symbol resembling a cloverleaf.

Command Line Interface (CLI): A way of accessing a computer, based on typing commands rather than selecting icons and menu items (compare with GUI).

Command: A word or phrase, usually found in a menu, that you choose in order to carry out an action. You choose a command from a menu, or type a command at the MS-DOS prompt. Some commands are Format, Edit, Open, etc.

Command Line: Commands you type to run an application. You can type commands at an MS-DOS prompt or in the Run dialog box in the Program Manager of Windows. Interfaces in which you type commands rather than choose them from a menu are often called command line interfaces. MS-DOS has a command line interface while the Macintosh does not.

Command Prompt: Usually refers to the MS-DOS prompt. The character or characters that appear at the beginning of the command line (usually "C:"), indicating that the computer is ready to recieve input.

Compiler: A program which translates source code written in a particular programing language into computer-readable machine code that can be executed on its own. Compare with Interpreter.

Concentrator: permits you to position machines closer together on the network cable than you could otherwise. If you use a twisted-pair cable, you need a concentrator.

CONFIG.SYS: A text file that DOS reads when booting which instructs the computer about the configuration of the machine. Config.sys contains configuration commands which enable or disable system features, set limits on resources, and extend the operating system functionality by loading device drivers.

Control Characters: ASCII characters which do not print but give instructions to the computer- usually found in word processors or telecommunications programs.

Conventional Memory: In an IBM PC or compatible computer, up to the first 640K of memory in your computer. MS-DOS by default uses only this memory to run programs.

Copland: A new version of Macintosh system software under development, scheduled to be released by 1997.

Coprocessor: An additional processor chip which increases the computer's speed by handling specialized chores such as math or graphics.

CPU: Central Processing Unit. Refers either to the principle microchip that the computer is built around (such as the Pentium or PowerPC chip) or the box that houses the main components of the computer.

CRT: Cathode Ray Tube. A television-like video tube which is the main component in most monitors.

CU-SeeMe: A videoconferencing protocol produced by Cornell University. Enables real-time video and audio connection over TCP/IP. Supported on Macintosh and PC platforms.

Cursor: Sometimes called a pointer. An icon on the screen that moves when the computer's mouse is moved, allowing the user to "point" to a command or position on the screen.

CYMB: Cyan, Yellow, Magenta, and Black. A color model used for specifying the color of printed matter. This corresponds to the 4 colors of inks used in most color printers. See also RGB and HLS, common models used to specify colors on monitors.

Daisy Chain: A method of connecting devices on a bus. On a daisy chained bus, devices not requesting a signal respond to it by passing it on. The daisy chain scheme permits assignment of device priorities based on the electrical position of the device on the bus.

Database: A structured set of data, normally associated with software to access and manipulate that data

Data file: See document.

DCA: Document Content Architecture. IBM's specifications for a standard word processing format. Not widely used.

Debugger: A program or part of a program which aids in locating and correcting errors (bugs) in program code. It is said that the original bug was in fact a moth which found its way into an early computer and caused it to malfunction.

Default Button: In some dialog boxes, the command button that is selected automatically if you press Enter or Return. In most graphical user interfaces (GUIs) default buttons have a bold border around them.

Degauss: On monitors, a process that demagnetizes the metal components in the CRT, thus eliminating image distortion that can result from magnetic charges acquired by the components. Some new monitors degauss automatically whenever you turn on your monitor.

Desktop: The term for the screen background in most graphical user interfaces (GUIs) on which windows, icons, and dialog boxes appear.

Device: A component of the system's hardware configuration, such as a modem, printer, mouse, sound card, or disk drive.

Device Driver: Software that controls how a computer communicates with a device, such as a printer. For example, a printer driver translates information from the computer into information the printer can understand.

Dialog Box: Also called a Panel in some graphical user interfaces (GUIs). A small window that appears temporarily to request information or to alert you to a condition. Dialog boxes usually request a response such as Ok to continue or Cancel to stop an operation.

DIMM: Dual Inline Memory Module. A type of pre-assembled RAM unit, used in some new computers, including the Macintosh PCI models. DIMMs support a wider data path than SIMMs, allowing faster memory access.

Dimmed: A term usually used in GUIs to indicate that a particular command is not available or is disabled. Also sometimes referred to as grayed out.

DIP Switch: Dual Inline Package. Small on-off switches mounted in computer hardware for purposes of user configuration. When adding expansion cards to computers, DIP switches must often be set to make the card compatible with the computer's configuration.

Direction Keys: Also called Arrow Keys. Keys used at times to navigate around the screen- especially in text areas. Direction keys have arrows pointing up, down, right, and left.

Directory: Part of a structure for organizing your files on a disk. A directory can contain files and other directories (called subdirectories). Directories are often referred to as folders on computers with GUIs.

Disk: A medium for storing information. Information stored on a disk remains there even when you turn your computer off, unlike information stored in memory (RAM). A floppy disk can be inserted and removed from a floppy disk drive, whereas a hard disk is permanently mounted inside its drive.

Disk Cache: A portion of RAM set aside for temporarily holding information read from a disk. It often makes data retrieval faster.

Disk Drive: The mechanism that holds and spins a disk, reading and writing data to it.

Display Adaptor: Hardware that converts (adapts) information in video memory to video output.

Dithered Color: A color produced by a pattern of differently colored dots that simulate the desired color. A solid color on one device (such as a 256-color monitor) may be a dithered color on another device. Also knows as nonsolid color.

Document: A data file. Whatever you create with an application, including information you type, edit, view, or save. A document may be a business report, a picture, or a letter and is stored as a file on a disk.

Document Window: In most graphical user interfaces (GUIs), a window within an application window. There can be more than one document window open at a time.

Domain: Part of the Internet Protocol (IP) address, used to identify the organization or local network that a local host is connected to. For example: uchicago.edu

DOS: See MS-DOS.

Double-click: Clicking a mouse button twice in quick succession. Used in most GUIs to "open" an icon.

Download: To transfer data or code from one computer to another. The distinction between downloading and uploading is hazy but downloading often refers to transfer from a larger server system (especially a mainframe) to a smaller client system, especially a microcomputer or specialised peripheral.

Downloadable Font: See soft font.

DPI: Dots Per Inch. Used in discussing the density with which a printer can print or a monitor can display. Describes the size of the pixels or dots of ink.

Drag: An action performed using a mouse. Used to move icons on the screen and in selecting commands from menus. Position the cursor/pointer on an item, press and hold the mouse button, move the cursor to a new location (by sliding the mouse), and then release the mouse button.

Drive Letter: The letter assigned to a drive on an IBM PC or compatible computer- for example, C. A and B usually refer to floppy drives and C to a hard drive.

Dual-Scan Display: A variant of a passive matrix display in which the top and bottom half of the screen are refreshed simultaneously, allowing the screen to be refreshed twice as fast, yielding better display quality.

EIDE: Enhanced Integrated Drive Electronics. A newer version of the IDE standard for hard drives.

EISA: Extended Industry Standard Architecture. A bus standard for IBM PC and compatible computers, that extends the AT bus to be 32 bits.

Electronic Mail (E-Mail): A method of transferring information (often text messages) from one computer to another over a network.

EMS: See Expanded Memory Specification.

Emulation: A process by which a computer imitates the actions of another computer, so that the imitating system accepts the same data and executes the same computer programs as the imitated system.

Emulation Mode: A special mode in which a device such as a printer can emulate the actions of a different device. Communications programs commonly emulate terminals.

Environment variable: Environment information, such as a drive, path, or filename, associated with a symbolic name that can be used by MS-DOS. You use the MS-DOS SET command to define environment variables.

EPROM: Erasable Programmable Read-Only Memory. A computer chip which can be erased and written to but which will not lose its information when a computer is turned off.

ESDI: Enhanced Small-Device Interface. One type of hard drive specification for IBM PC and compatible computer.

Ethernet: A popular networking technology featuring 10Mbps transmission speeds, running over thin coaxial (10Base-2), thick coaxial (10Base-5), or twisted pair (10Base-T) cables. Ethernet will support TCP/IP, AppleTalk (EtherTalk), Novell Netware, and other communication protocols.

EtherTalk: An implementation of the AppleTalk communications protocol that runs over ethernet.

Expanded Memory (EMS): Memory beyond the 640K limit of usable RAM in DOS which conforms to the Lotus-Intel-Microsoft (LIM) specifications for expanded memory. This memory is available only to DOS applications that can support it. It is an older standard which is being replaced by extended memory.

Extended Memory: In an IBM or compatible PC, the memory above the 1Mb address range. Uses XMS (eXtended Memory Specification).

Extended-memory Manager: On an IBM PC or compatible computer, a program that prevents different applications from using the same part of extended memory at the same time.

Extension: 1) The period and up to three characters at the end of a filename. An extension usually identifies the kind of information a file contains. For example, text file often have the extension .TXT. Derived from the MS-DOS operating system but the convention is often used in other operating systems to help quickly determine the file type. 2) A special file used on Macintosh computers to add extra functionality to the system. These files are stored in the Extensions folder of the System folder.

FAT: 1) File Allocation Table. A special file in which MS-DOS stores information on the layout of a disk. This file is critical; if it is damaged, it is extremely difficult to get information from the disk. 2) AN application which is compiled with code to run on two platforms, for example both the 680x0 based and PowerPC based Macs.

FAX/Data modem: A modem which can handle FAX protocols and also transmit data. Some older modems can only either send faxes or receive them; most can do both.

File: A program, document, utility- anything that isn't hardware on a computer. A file might contain a memo, a drawing done in a graphics application, or a program itself.

File Server: A computer that provides networked computers with access to shareable resources. A dedicated file server can be used only as a file server while it is on the network. A non-dedicated file server can be used simultaneously as a file server and a workstation.

File Sharing: Provisions in the networking system software which allow more than one user to access the same file.

Finder: An essential component of the Macintosh system software. The Finder provides the interface to the Macintosh. It is the program that is running when you start the Macintosh which allows you to view lists of and manipulate files.

Firmware: Programs written permanently into ROM chips.

Fixed Disk: See hard disk.

Fixed-width Font: Also called a monospaced font. A font in which all characters have uniform widths, such as Courier. Contrast with proportional font.

Floating Point Unit (FPU): A coprocessor that provides hardware routines for mathematical function, to be used with a CPU that does not have those functions built in. The 680x0 and 80x86 line of CPU chips had FPU chips available. Current CPUs (such as the PowerPC and the Pentium chips) incorporate floating point functions and do not need a separate FPU.

Floppy Disk: A disk which is covered with protective packaging and can be removed from its drive. Currently, floppy disks are generally 3.5 inches wide. The protective covering on 3.5"_disks_is_hard plastics_prompting_some_to_think_that_these_are_hard_disks_but_they are_not.__The_media_inside_is_the_same_floppy_material_as_that_inside the_older_5.25" disks. Floppy disks also come in different densities and care must be taken to use a disk of appropriate density or data may be lost from the disk. Floppy disks are noted for their relatively slow speed, small capacity, and low price.

Flow Control: Also called handshake. The processes used to regulate the rate at which information is transferred from one device to another. One device sends a signal to the other when information can be transferred.

Folder: A graphical representation of a directory or subdirectory. On the Macintosh and some other graphical user interfaces (GUIs). Folders contain files and other folders.

Font: A set of letters, numbers, punctuation marks, and symbols that are a given size and design. Some fonts can be scaled to any size while others are a fixed size. Outline fonts, TrueType fonts and PostScript fonts are examples of scaleable fonts.

Font Cartridge: A font contained in a cartridge that physically plugs into your printer. Font cartridges are used by laser printers such as those in the HP LaserJet family, but some dot-matrix printers also use font cartridges.

Font Family: A group designation that describes the general look of a font. For example, the Roman font family contains proportionately spaced fonts with serifs.

Font size: See point size

Footer: Text that appears at the bottom of document pages when they are printed. Compare with header.

Foreground: The area of the Screen that the active window occupies. Contrast with background.

Format: (1)Preparing a disk for use by your hardware and operating system. Also called Initializing. When the computer initializes a disk, it also destroys any information already there (just as recordinging on a cassette tape replaces what was previously there with what you record). (2)Formatting also refers to the way text is set up on a page (underlining, bold, indenting, etc.) (3)The way information is structured in a file, often specific to a particular application.

FPU: See Floating Point Unit.

Freeware: Software that is provided without charge. Contrast with shareware.

FTP: File Transfer Protocol. Allows users to copy files between the local system and any system reachable over the network. Every UNIX system has ftp and there are version for the Macintosh and Windows. A common way to make software (text files, sounds, pictures, utilities, etc.) available is to put it on an anonymous ftp server. Anonymous ftp servers allow users to login without a password, specifying "guest" as the user, and then copy whatever has been made available.

Gateway: Transfers information between physically separate networks that are based on differing protocols (for example, between Internet and AppleTalk networks). It performs high-level information translation, while routers provide low-level.

GIF: Graphic Interchange Format. A popular file format for graphic images, created by CompuServe. The GIF format features image compression.

Gigabyte: 1,000 Megabytes. Abbreviated GB.

Gopher: A means of distributing information by computer. Using gopher, your client "burrows" through the Internet to various sites where you can access documents and services. In addition to text documents, some gopher clients can give you access to pictures, sounds, and interactive sessions.

GPF: General Protection Fault. In Windows, the memory protection hardware detected an illegal memory instruction from a program, causing the program to crash.

Graphical User Interface (GUI): A way of interacting with a computer, based on graphics instead of text. GUIs use icons, pictures, and menus, and use a mouse as well as a keyboard to accept input. MacOS, MS Windows, and the X windowing system all use GUIs. Contrast with Command Line Interfaces (CLI).

Graphics Mode: The mode that enables applications to display images in addition to text. Windows applications always run in graphics mode whereas MS-DOS applications ran in either graphics or text mode.

GUI: See Graphical User Interface.

Handshake: See flow control.

Hard disk: A disk drive which contains one or more disks (which are hard platters rather than floppy disks) permanently sealed in it. Hard disks are noted for their speed and high capacity.

Hardware: Computer machinery, such as the CPU, disk drives, monitor, and printer. Contrast with software.

Hardware Handshaking: Hardware (usually a modem cable) which handles handshaking (data flow control) automatically. Most new modem cables have hardware handshaking.

Header: Text that appears at the top of every page of a document when it is printed. Compare with footer.

Hidden File: A file that is not intended to be viewed in a directory listing. In MS-DOS, the system files IO.SYS and MSDOS.SYS are hidden; in Windows, the swap file. Some operating systems allow the user to hide files so that they can only be accessed if the name is known.

High Memory Area (HMA): The first 64K of extended memory in an IBM PC or compatible computer. This area is used by Windows and by some applications. MS-DOS can also be "loaded_high"- loaded into the HMA to make more room in conventional memory.

Highlighted: Indicates that an object or text is selected and will be affected by your next action. Highlighted text appears in reverse video on monochrome monitors and in a chosen color on color monitors. Highlighted objects may change color or be surrounded by some sort of selection cursor.

Hierarchical Menu: Also called a Submenu or Cascading menu. A secondary menu that appears while dragging and holding the cursor over an item in a menu. It gives you choices of options that apply to the item you are selecting in the menu.

HLS: Hue, Luminance, and Saturation. A Model for specifying colors, used for monitors. Television uses this model. Also common in computer applications is RGB. CYMB is used for printers. HLS is also called HSI (hue, saturation, intensity) or HSV (hue, saturation, value).

HMA: See High Memory Area.

Hot Key: A keystroke or combination of keystrokes intended for activating a RAM-resident program on IBM PC and compatible computers.

HTML: Hypertext Markup Language. The language used to create and define a WWW web page. This language is used to define the locations and characteristics of each element of the page.

HTTP: Hypertext Transfer Protocol. The protocol used for transfering html and related files, usually from WWW sites.

HSI: See HLS.

Hue: Position of a color along the color spectrum. For example, purple is between red and blue. Luminance and saturation also affect the appearance of a color.

HyperCard: Application toolkit for Macintosh computers, which provide an easy method of creating hypertext presentations. Currently, a HyperCard player comes free with Macintosh computers.

I/O Address: Locations within the input/output address space of an IBM PC or compatible computer used by a device, such as a printer or modem. The address is used for communication between software and the device.

Icon: A simple picture used to denote a program, command, file, or concept in a GUI such as Windows or the Macintosh.

IBM: International Business Machines. Very large company that makes a variety of computers. IBM set the standard for DOS machines. Currently, many companies makes clones of IBM's personal computers which are often called compatibles.

IDE: Integrated Drive Electronics. One type of hard drive specification for IBM PC and compatible computers, also used in some Macintoshes.

IEEE 1284 Bidirectional Printer Cable: This is the specification for a standard parallel printer cable.

IMAP4
Internet Message Access Protocol (IMAP) is a standard protocol for accessing e-mail from your local server. IMAP (the latest version is IMAP4) is a client/server protocol in which e-mail is received and held for you by your Internet server. You (or your e-mail client) can view just the heading and the sender of the letter and then decide whether to download the mail. You can also create and manipulate folders or mailboxes on the server, delete messages, or search for certain parts or an entire note. IMAP requires continual access to the server during the time that you are working with your mail.

A less sophisticated protocol is Post Office Protocol 3 (POP3). With POP3, your mail is saved for you in your mail box on the server. When you read your mail, all of it is immediately downloaded to your computer and no longer maintained on the server.
IMAP can be thought of as a remote file server. POP can be thought of as a "store-and-forward" service.
POP and IMAP deal with the receiving of e-mail from your local server and are not to be confused with Simple Mail Transfer Protocol (SMTP), a protocol for transferring e-mail between points on the Internet. You send e-mail with SMTP and a mail handler receives it on your recipient's behalf. Then the mail is read using POP or IMAP.

Import: To move an item or file into an application or environment which is different than that native to it. The file is converted to the new format while attempting to change as little as possible about the appearance of the file when printed. For instance, MS Word for the Macintosh is able to import files from a few MS-DOS word processors.

Indigo: RISC-based workstation made by Silicon Graphics that supports high-speed 2-D graphics and digital audio. The Indigo uses display PostScript.

Indigo2: A higher end Indigo designed for 3D graphics.

Indy: a lower end workstation from Silicon Graphics.

Initialization Files: (1)In Windows, files with the extension .INI. They contain information that defines your Windows environment. (2)Called INITs on the Macintosh. Files which load when the computer starts up which change the way the computer normally behaves. One INIT allows you to access MS-DOS disks on the Mac. Another makes Oscar the Grouch sing whenever you throw trash away. In System 7, INITs are called extensions.

Initialize: (1) See Format. (2) To set or reset hardware, usually printers.

Insertion Point: vertical bar in a text area which indicates where text that you type will be entered.

Intel: Maker of the 80x86 and Pentium lines of processors which are used in IBM PC and compatible computers.

Interface: Part of a computer, program, or peripheral that communicates with other components. Interface also refers to the user interface.

Internet: A worldwide collection of interconnected networks, providing a wide variety of services, using the TCP/IP network protocols.

Interpreter: A program that reads and executes source code one line at a time. Does not create an executable file that can run independently. Compare to compiler.

Interrupt: On IBM PC and compatible computers. A signal that a device sends to the computer when the device is ready to accept or send information. See interupt request (IRQ).

Interrupt Request: On IBM PC and compatible computers. Hardware lines over which devices can send interrupts. Typically each device connected to the computer uses a separate IRQ. It is a good idea to know which IRQ each device on your computer is using (the IRQ for the mouse and keyboard should be found in your manuals). Expansion cards such as Ethernet cards or token ring adaptors also use IRQs. Setting the IRQ so that it does not conflict with (use the same IRQ as) other devices is an essential part of installing expansion cards and new devices.

IRQ: See Interrupt Request

IRIX: A version of Unix for Silicon Graphics machines.

ISA: Industry Standard Architecture. One standard for IBM and compatible computers that specifies the architecture of the hardware.

I-beam: Appearance of the cursor/pointer in graphical user interfaces (GUIs) when it is positioned over an area in which text can be entered.

Java: A platform-independent programming language, produced by Sun Microsystems. Java is built as a method to provide services over the WWW. With Java, a Web site provides a Java application (called an applet) which is downloaded by the client and executed on the client machine. Java is specifically built so that an application can be run on any kind of system, so a separate Mac, Windows, Sun, etc. version is not needed. Java also has some security features built in, to make it more difficult for destructive applets to be written. Java is based on a subset of the C programming language.

JPEG: A format for compressed graphic images, which produces much smaller files than GIFs. The compression algorithm is a lossy one, however, which will not reproduce the original image exactly. Various settings are available, to allow more compression at the cost of a greater loss of image quality.

K: See kilobyte

Keyboard Buffer: A temporary storage area in memory that keeps track of keys that you typed, even if the computer did not immediately respond to the keys when you typed them.

Keyboard Command: See shortcut key.

Kilobyte: 1024 bytes (about 1000 bytes hence kilobyte). Usually abbreviated K, as in 640K. Used in discussing memory and hard drive storage.

L2 Cache: Level 2 Cache. Memory cache that is between the CPU and the main memory (level 1 cache is a memory cache that is onboard the CPU chip itself). L2 cache can provide faster CPU access to instructions and data in memory, thus increasing system performance.

LAN: Local Area Network. A group of personal computers linked together in order to share programs, data, and peripherals.

Laser Printer: A printer that uses a laser beam to produce fast, high-quality output.

LCD: Liquid Crystal Display. Technology used for portable computer displays, as well as many other electonics display applications, such as watches, etc. LCD displays for portables are usually active matrix, passive matrix, and dual scan displays.

LED: Light-Emitting Diode. Used for display in some electronic devices.

LIM-EMS: Lotus Intel Microsoft Expanded Memory Specification. See expanded memory.

Line conditioner: An electrical device (often part of a UPS) that ensures a constant level of electricity, by cleaning up any fluctuations in voltage.

Linker: A program which can combine several machine language files into an executable program.

LocalTalk: The network hardware built into Macintosh computers. LocalTalk hardware handles the AppleTalk protocol.

LPT1: The name used by MS-DOS to refer to the first parallel port on a computer. The second parallel port, if there is one, is LPT2. The printer is usually connected to LPT1.

Luminance: The measure of the brightness of a color. luminance corresponds to the total amount of light coming from a given surface area. Luminance, also called lightness or intensity, is used along with hue and saturation, in the HLS color model.

MacBinary: A file format for transferring Macintosh files between different computer platforms, that allows the separate data and resource forks of the Macintosh to be stored together in a datafork. MacBinary files are distinguished by the .bin file extension. Binhex is generally preferred over MacBinary.

Macintosh: Computer developed by Apple Computers, first released in 1984. The Macintosh was one of the first computers to use a graphical user interface. Today, Apple continues to produce many different models of Macintosh.

MacOS: The operating system produced by Apple for their Macintosh computers.

Macro: A sequence of commands and/or data input that has been stored for the purpose of fast and easy playback.

Math Coprocessor: See Floating Point Unit.

Mbps: Megabits per second (one million bits per second). Speed at which data is transferred. Hopefully as modems and serial transmissions become faster, Mbps will be used to discuss their speed.

Mb: See Megabyte.

Media: Items used to hold data, including floppy disks, hard disks, tapes, CD-R0Ms, etc.

Megabyte: 1024 kilobytes (about one million bytes hence megabyte). Usually abbreviated Mb or MB as in 30 Mb.

MegaFLOPS: Million Floating point Operations Per Second. A measure of computing power; specifically, the speed at which certain mathematical functions are performed. Also called MFLOPS.

Megahertz (Mhz): Describes the speed at which a computer runs. Abbreviated MHz or Mhz. Do not take the speed at which a processor runs to be absolute. For instance a machine with a PowerPC processor running at 90 MHz may perform some tasks more quickly than an Pentium machine running at 120 MHz, and the Pentium may be faster at others.

Memory: A temporary storage area for information and applications. RAM, ROM, conventional memory, expanded memory, and extended memory are all different types of memory. RAM and hard disk space should not be confused. RAM is temporary storage while the hard disk offers semi-permanent storage.

Memory Protection: A capability of some operating systems to control a program's access to memory, so that one program cannot corrupt the memory allocated to another program. Memory protection will often allow a single program to crash without affecting other programs, or the system as a whole.

Memory Resident Program: See TSR.

Menu: A screen image displaying a series of options from which the user can choose.

Menu Bar: A one-line, horizontal menu at the top of the screen; usually found in GUIs.

MFLOPS: Million Floating point Operations Per Second.

MHz: See Megahertz

Micro Channel Architecture (MCA): A bus standard developed by IBM for the high-end models of their PS/2 line of personal computers. MCA is no longer used.

Microchip: A small, silicon object containing microscopic circuitry.

Microsoft: A huge software company founded and run by Bill Gates. Microsoft produces MS-DOS and Windows. Microsoft also produces a number of applications including Word for Windows and the Macintosh, Excel for Windows and the Macintosh, and Flight Simulator.

MIDI: Musical Instrument Digital Interface. A standard protocol for communication between electronic musical instruments and computers.

MIME: Multipurpose Internet Mail Extension. A standard for transferring binary information (such as sound and graphics files, or word processing files with embedded formatting codes) over e-mail.

MIPS: Millions of Instructions per Second. The execution speed of a computer. For instance, 5 MIPS is 5,000,000 instructions per second. Modern personal computers often perform at 100 MIPS. MIPS rates are not uniform. Some are averages while some are peak performances. In addition, it takes more instructions on some machines to perform the same function (RISC vs. CISC, mainframe vs. micro). Because of this, MIPS are sometimes called "MisInformation_to Promote_Sales." The MIPS rate is just one factor in overall performace. Bus and channel speed and bandwidth, memory speed, memory management techniques and system software also affect total throughput.

Modem: Modulate-Demodulate. A communications device that enables a computer to transmit information over a telephone line.

Monochrome: A monitor that displays only one color. Some monochrome monitors can also display various shades of gray and are called gray-scale monitors.

Monitor: A hardware device used to display the visual output of a computer. Uses a CRT tube (the same tube used in a TV).

Monospaced Font: See Fixed-width font

Mosaic: A freeware Web browser, developed by the NCSA (National Center for Supercomputing Applications).

Motherboard: The main circuit board in a computer. The CPU is located on the motherboard.

Motorola: Manufacturer of computer chips. Makes the 680x0 chip family, and is part of the industry group that developed the PowerPC chips.

Mouse: A mouse is a small device with a ball on the bottom. As you move the mouse across a surface, the ball turns, turning receptors inside the mouse. These receptors send signals to the computer which cause a pointer or cursor on screen to move in a way which corresponds to the direction and speed the mouse was moved (Try turning the mouse backward- away from the computer- and moving it.). There are also optical mouses, that track the motion of the mouse by reflecting light off of a special mouse pad.

MPEG: Moving Pictures Experts Group. A standard for compressed audio and video data. This is a "lossy" compression scheme, which means the data loses some quality in compression. The standard specifies a bandwidth of 150 Kbytes per second, which is the data rate of audio CD's.

MS-DOS: Microsoft Disk Operating System. The most common operating system for IBM and compatible PCs. Produced by Microsoft. Sometimes referred to simply as DOS.

MS-DOS Prompt: See command prompt.

Multimedia: Computer applications involving text, graphics, audio and video, or computers that are (or claim to be) designed to provide high quality graphics and audio. Multimedia is largely associated with CD-ROM, because the large amounts of data involved are provided best by CD-ROM.

Multiprocessor: A computer system that uses more than one CPU running in parallel for faster performance.

MultiSync: In a monitor, the ability to run at different scan rates, allowing the monitor to display different resolutions.

Multitasking: The ability to run more than one program at the same time. There are different types of multitasking. Cooperative multitasking requires a program to be written to allow other programs to access the system. In preemptive multitasking, the system can suspend any program to allow other programs access. Preemptive multitasking provides better performance, as programs can switch with less overhead. The Macintosh and Windows 3.1 use cooperative multitasking. Windows 95 and Unix use preemptive multitasking.

Multithreading: The ability to have more than one task occurring in an application. For example, you could have a large spreadsheet calculate values while continuing to use that spreadsheet or print a complicated document while continuing to work on that document. OS/2 has multithreading capabilities. Applications must be written according to certain specifications in order to multithread.

Netscape: A commercial web browser for the Macintosh, Windows, and the X windowing system. Netscape is currently free to educational users.

Network: A group of computers connected by cables or other means and using software that enables them to exchange information and share equipment (such as printers and disk drives).

NeXT: Defunct computer designed by Steve Jobs, one of the originators of the Macintosh. The company that made the NeXT computers. The NeXT was a workstation running NeXTStep, a version of Unix. NeXTStep uses a GUI, and runs Display PostScript. NeXTStep is still available for machines running on the 486, SPARC, and HP Alpha processors.

NFS: Network File System. A networking protocol suite developed by Sun Microsystems and used widely in the Unix world. Used to share directory trees across a network.

Node: A personal computer hooked up to a network. Any network station.

Nonsolid color: See dithered color.

Notebook: Small compact computer. Smaller than a portable. Measurements are usually about 8.5 x 11 inches.

Object Linking and Embedding (OLE): A proprietary software system from Microsoft that allows applications to transfer and share information. When a change is made to a shared object in the original application, any document that contains that object is updated automatically to reflect the changes.

Object-Oriented Graphics: Graphic designs that are handled by the computer as mathematically-described shapes, rather than as collections of pixels. Often referred to as drawing as opposed to painting.

Objective C: A programming language based on the "C" programming language, featuring a greater emphasis on hierarchical design of programs.

OLE: See Object Linking and Embedding.

Open: To display the contents of a file in an application or to start an application.

Open Architecture: A type of IBM PC and compatible architecture that allows third party manufacturers to produce additional interior add-ons (usually circuit boards), and to allow users to easily install these add-ons.

OpenDoc: A standard for applications and documents created by a consortium of Apple, IBM, and Novell. OpenDoc is intended to provide more cross platform and cross application integration, by splitting up the components of documents (text, sound, graphics, etc.) and providing separate access to each component through modular software.

Open Transport: The new networking section of the HREF="gloss3.htm#MACINTOSH">Macintosh system software. Available in System 7.5.2 for PCI Macintosh models. This package integrates control of Ethernet and Localtalk, and the implementation of AppleTalk and TCP/IP. System 7.5.3 will contain Open Transport for all Macintosh models.

Operating System: The system software. There are a number of different operating systems, which have different design philosophies, provide different facilities, and have different looks and feels. Among popular operating systems are MacOS, MS-DOS, the various incarnations of Windows, Unix in its various flavors, OS/2, etc.

Option: Also called parameter in MS-DOS. Parameters are used to control how a command is carried out. Typically a parameter starts with a slash. For example to format a disk as 720K in a high density drive, you would issue the format command with the f parameter:format /f:720.

OS/2: Operating System/2. A multitasking and multithreading operating system developed by IBM and originally Microsoft for use on the 80x86 computers. OS/2 Warp is the current version of OS/2, and has received attention as a possible replacement (and improvement) for both DOS and Windows since it can run DOS, Windows, and OS/2 applications.

OS/2 Warp: The current version of OS/2.

P6: See Pentium Pro.

P7: The code name for a forthcoming CPU chip from Intel.

Panel: See dialog box.

Pantone: System of color matching designed to ensure that color output will be the color intended whether on-screen or in output from a printer.

Parallel Interface: An interface between a computer and a printer in which the computer sends multiple bits of information to the printer simultaneously. Centronics interface is another name for parallel (which is different from Centronics SCSI, however).

Parallel Port: A connection on an IBM PC or compatible computer, usually named LPT1, where you plug in a cable for a parallel printer. Some computers have more than one parallel port and are labeled LPT2, LPT3, etc.

Parallel Printer: A printer with a parallel interface, which you connect to a parallel port.

Parameter: See option.

Parity: An error-checking procedure in which the number of 1s must always be the same- either even or odd- for each group of bits transmitted without error. The parity setting is often important in communications. If you are having difficulty with a modem, check the parity; it can be odd, even, or none.

Pascal: A high-level, usually compiled programming language originally designed for teaching programming.

Passive Matrix Display: A type of LCD screen used on portable computers in which parallel wires are run both horizontally and vertically in front and behind the display. Pixels are turned on when both the horizontal and vertical wires which intersect the pixel are energized. Residual current in the wires can partially activate other pixels, and reduce contrast in the display. For this reason, the passive matrix display is considered inferior to the active matrix LCD. See also Dual-Scan Display.

Password: Once secret word or phrase spoken to a guard to gain admission. Passwords are now commonly used to protect computer resources. You may need to enter a password when you turn on your computer, to use a printer, or to gain access to a network resource. When selecting a password, do not use your name or any part of it. Do not use words that are found in a dictionary or that are common around your office. Secure passwords should contain a combination of upper and lower case letters and may contain symbols or numbers.

Path: Specifies the location of a file. For example (in MS-DOS), the path of the file BOB.DOC which is located in the DOCUMENT directory in the SALES directory on the C drive, is C:\SALES\DOCUMENT\BOB.DOC. Paths are applicable to every operating system that uses directories.

PC-DOS: Personal Computer Disk Operating System. A version of MS-DOS licensed by IBM for use on its personal computers.

PC: Personal Computer. Strictly speaking, this refers to the IBM PC, which is any IBM-manufactured personal computer made prior to the PS/2 Series. Usually PC refers to any personal computer compatible with IBMs. It is also used to refer to any personal computer.

PC Card: See PCMCIA.

PCI: Peripheral Component Interconnect. A new standard computer bus, common to newer Macintosh and Pentium machines. This bus features faster bus throughput, as well as hardware compatibility across computer platforms, so a card could be used on both a PCI Mac and a PCI pentium machine, though different software drivers would be needed..

PCMCIA: A standard for hardware expansion, mainly for notebook computers. PCMCIA is supported by Macintosh and IBM compatible notebooks, and features ease of use. Often simply called a PC Card.

PDF: Portable Document Format. A Text format designed by Adobe, to be read by the Adobe Acrobat Reader. PDF is designed to be portable across computer platforms.

Pel: See Pixel.

Pentium: A CPU chip produced by Intel, used in IBM compatible machines. The Pentium is the equivalent of the 586 (of the 80x86 chip family).

Pentium Pro: A CPU chip produced by Intel, which has some substantial architectural changes from the Pentium, including a built in L2 cache. The Pentium Pro was called P6 during development.

Peripheral: A hardware item that can be attached to a computer to increase its functionality, such as a printer or monitor.

PGP: Pretty Good Privacy. A freeeware system for providing security for file transfers (e-mail, etc.) through file encryption.

Ph: An online directory database system. Used to get info on University people, and used at the UofC for authentication for SLIP access and the ovid database (with the user's Ph password). The Ph database's information is not necessarily up to date.

PIF: Program Information File. A file that provides information about how Windows should run a non-Windows application. For example, you use a PIF to direct Windows to run an MS-DOS application in a full screen rather than in a window, or to specify a start-up directory.

Pixel: Also called pel or picture element. The smallest graphic unit that can be displayed on the screen, usually a single-colored dot. Pel is abbreviated from picture element.

Plug and Play (PnP): A hardware standard for auto configuration, which requires operating system support. Currently, Windows 95 supports Plug and Play. Also slang for autoconfig.

PnP: See Plug and Play.

Point: A measurement of printed text. A single point is 1/72 of an inch. 12 points, abbreviated 12 pt., is the height of standard, 6 lines per inch, typewriter text.

Point Size: Also called font size. The height of a printed character specified in points.

Pointer: See Cursor.

Pointing Device: An input device you use to move the pointer on the screen, choose commands, press buttons, select text, create drawings, and so on. A mouse in a pointing device.

POP: Post Office Protocol. A protocol to allow single user machines to download e-mail from a server.

Pop-up Program: See TSR.

Port: A plug and its associated circuitry in a computer's hardware, used for sending data from computer to its peripherals or to other computers. Serial, parallel, and SCSI ports are commonly used ports.

POST: Power-On Self-Test. Test of internal circuitry, memory, and installed hardware that a computer does to itself when turned on.

PostScript: A language designed for describing text and graphics, usually built into high-end output devices such as laser printers and typesetters. Display PostScript is the use of PostScript for the computer's own display (on a monitor).

PowerPC: A new family of CPU chips, produced by an industry group including Motorola, IBM, and Apple. Used in Macintosh and other computers.

PowerPC Platform (PPCP): A standard hardware architecture developed by a consortium including Apple, IBM, and several other companies. PPCP machines use the PowerPC CPU and a PCI bus. A number of operating systems, including Copland, AIX, Windows NT, etc. should be able to run on PPCP machines. Also called the Common Hardware Reference Platform (CHRP).

PPCP: See PowerPC Platform.

PPP: Point to Point Protocol. An implementation of the TCP/IP protocol to be used over serial lines (modems). Allows direct access to the internet over a modem. Compare with SLIP, another such protocol.

PRAM: Parameter RAM. A special part of RAM on the Macintosh computer, where some system parameters are stored. This RAM is battery backed, to save the information even when the machine is turned off. P-RAM can become corrupted, causing erratic system behavior. A process called "zapping_the_P-RAM" can be used to clear the RAM area, to clear up some problems.

Prep: Used mainly of hard drives. See Format.

PReP: PowerPC Reference Platform. A system standard developed by IBM, to ensure compatibility between PowerPC computer systems. PReP has largely been superceded by PPCP (which integrates the PReP standard).

Press: Action performed using the mouse. Click the mouse button but do not release it. Continue to hold the mouse button. Pressing is used in selecting items from menus, dragging items, and using scroll bars.

Print Queue: A list of files that have been sent to a printer. The list indicates the file currently printing and those waiting to be printed.

Print Server: A device and/or program that manages shared printers.

Printer Driver: A series of instructions that allow a program to communicate with a specific printer.

Printer Fonts: Fonts that are stored in your printer's memory, or soft fonts that are sent to your printer before a document is printed. Because the font works only with the printer, the operating system (or environment) must either approximate the font on-screen or separate screen versions must be installed.

Program: See application.

Program File: On an IBM PC or compatible computer, an executable file that starts an application or program. A program file has an .EXE, .PIF, .COM, or .BAT filename extension.

Program Information File: See PIF.

Proportional Font: A font in which different characters have varying widths, such as Times. Contrast with fixed-width font.

Protected Mode: An IBM PC or compatible computer's operating mode that is capable of addressing extended memory directly. Keeps applications in memory from addressing the same memory location.

Protocol: Rules for communicating, particularly for the format and transmission of data.

Queue: A list of files that have been sent to a device such as a printer. The list indicates the file currently being acted on by the device (printed) and those waiting to be acted on (printed).

QWERTY: Name of the standard American-English keyboard. The letters keys in the top row from left to right are "Q-W-E-R-T-Y," hence the name.

RAM: Random Access Memory. The memory that can be used by applications to perform necessary tasks while the computer is on. Memory chips that can hold easily changed information as long as there is an electric current running through them, but go blank when the electricity is cut off. The term "Random_Access" refers to the ability of a processor to immediately access any part of the memory. Many people confuse RAM and the hard disk. The RAM is temporary storage while the hard disk is semi-permanent storage. One way to understand the difference between the two is to relate RAM to short term memory and the hard disk to long term memory. Just as lots of memories are stored in your brain, lots of information is stored in a computer's hard drive. However, you can only actively think about and use a small portion of what you remember at any given time. This is similar to RAM. When a computer is using an application, it is loaded into RAM.

RAM Disk: Also called a virtual drive. A portion of RAM that is used as if it were a disk drive. RAM drives are much faster than hard disks because your computer can read information faster from memory than from a hard disk. However, information on a RAM drive is lost when you turn off or reboot your computer.

RAM-Resident: A program remaining in memory after it has returned control of the computer back to the operating system. RAM-resident programs either wait or operate in the background while applications are active. Also called TSRs (Terminate and Stay Resident) in IBM PC and compatible computers.

Raster Font: See screen font

Read-Only File: A file that you can read but cannot make changes to.

Real Audio: A software system for playing sound files in real time over the internet. Produced by Progressive Networks.

Repeater: A device used in networks to extend cabling distances by amplifying or regenerating signals. Used to join lengths of network cables, or to split a network cable into multiple segments. You might also find repeaters useful if you want to use different types of cable in your network. For example, you could connect an Ethernet network with 10Base-T cable to one on a thick cable.

Resolution: Indicates the number of dots (or pixels) that make up an image on a screen or printer. The higher the resolution, the finer and smoother images can appear when displayed at a given size.

RGB: Red, Green, Blue. A standard way of specifying colors on a computer monitor. Stands for the three (additive) primary colors; that is, the primary colors when light is added together to produce the color. Red, yellow, and blue are the primary colors when ink is blended and put onto (white) paper. CYMB (Cyan, yellow, magenta, black) is the color model used for printing (this does corespond to the standard blue, yellow, red usage). An alternative model is saturation, hue, and luminance (this is the way television color is encoded. Computers sometimes use this model).

RISC: Reduced Instruction Set Computer. A type of CPU architecture in which the CPU has a small(er) set of computer instructions that it can perform. Different instructions are combined to provide the functionality of other CPUs with more instructions (see CISC). The greater speed that the instructions can be carried out at is thought to more than make up for the fact that fewer instructions are supported. There is a growing consensus that RISC processors have more potential for speed than CISC processors do.

ROM: Read-Only Memory. A chip or chips with information- usually a program- written into them at the time of their manufacture. These chips cannot be re-written, hence "read-only." The contents of ROM remains even when the computer is turned off.

Root: The top-level directory of a disk. In Unix, it is also a name for the "superuser" account.

Root Folder: The top-level folder of a disk.

Router: Hardware and software that routes data between similar or dissimilar networks on the protocol level. Routers can support more than one protocol. Routers are used in some places on the U of C campus to allow AppleTalk networks to connect to the backbone of the campus EtherNet network. Routers can actively direct messages between separate networks (for example, an Ethernet network and a token ring network). They make decisions about which path through the network traffic will follow. Each network connected by the router has a unique identity with its own Internet address.

RTF: Rich Text Format. A word processing file standard. RTF attempts to maintain some aspects of document formatting during transfers and conversions.

Saturation: The purity of a color's hue, moving from gray to the pure color. A high saturation corresponds to a strong color. Hue and luminance also affect the appearance of a color, in the HLS color model.

Scaleable Typeface: A set of letters, numbers, punctuation marks, and symbols (that is, a font) that are a given design but can be scaled to any size.

Screen Font: Also called a raster font. The font that is displayed on your screen, which may approximate a printer font so that documents look approximately the same on the screen as they do when printed.

Screen Saver: A moving picture or pattern that appears on your screen when you have not moved the mouse or pressed a key on the computer for a specified period of time. Screen savers prevent screen damage that is caused when the same areas of light and dark are displayed for long periods of time. Be careful when using a screen saver on a computer with an LCD screen (most laptops and notebooks). A pixel on an LCD screen is on when its dark; therefore, blacking the screen as some screen savers do would cause more damage.

Scroll: To move through text or graphics (up, down, left, or right) in order to see parts of the file or list that cannot fit on the screen.

Scroll Arrow: An arrow on either end of a scroll bar that you use to scroll through the contents of a window or list box.

Scroll Bar/Scroller: A bar that appears at the bottom and/or right (or left) edge of a window whose contents are not entirely visible. Each scroll bar contains a scroll box and two scroll arrows.

Scroll Box: In a scroll bar, the small box that shows the position of informtion currently in the window or list box relative to the contents of the entire window.

SCSI: Small Computer System Interface. A fast port used to connect computers with hard drives and other peripherals. Pronounced "scuzzy."

Select: To mark an item so that a subsequent action can be carried out on that item. You can usually select an item by clicking it with a mouse or pressing a key. After selecting an item, you choose the action that you want to affect the item.

Serial Interface: An interface between a computer and a serial device, such as a printer or modem, by which the computer sends single bits of information to the device, one after the other.

Serial Port: A port that transmits data a bit at a time, used for modems, mice, certain printers and communication devices.

Server: A network device that provides services to client stations. Servers include file servers, disk servers, print servers, etc.

Shadow: Shadowing BIOS in RAM. When an IBM PC or compatible computer boots, the BIOS code which is located in relatively slow read-only memory (ROM) is copied into write-protected memory locations in much faster RAM. This allows BIOS functions to execute more quickly.

Shareware: Publicly distributed software, for which the author requests payment. Payment may or may not buy additional functionality or support.

Shortcut Key: A key or key combination that you press to carry out a command or action. In Windows and on the Macintosh, if a command has a shortcut key, the key combination is listed to the right of the command name on the menu. On the NeXT, a key is listed to the right of the command name on the menu. You press the Command key along with that key. In MS-DOS and many DOS applications, one letter of a command is bolder, a different color, or underlined. To select that command, you may press that letter. Other operating systems may have other methods.

Silicon Graphics Incorporated: SGI. Makers of high-end graphics workstations.

SIMM: Single In-line Memory Module. A pre-assembled unit of RAM chips that is easier to install than individual chips. A memory board must be designed specifically to use SIMMs. Many computers use SIMMs, though some now use DIMMs.

SLIP: Serial Line Internet Protocol. An implementation of the TCP/IP protocol to be used over serial lines (modems). Allows direct access to the internet over a modem. Compare with PPP, another such protocol.

SMTP: Simple Mail Transfer Protocol. The protocol used to transfer E-mail between computers on the internet. It is a server to server protocol, so other protocols (like POP) are needed to transfer the E-mail to a client machine.

Soft Font: Also called downloadable font. A font, usually provided by a font vendor, that must be installed on your computer and sent to the printer before it can be printed.

Software: The set of instructions that make computer hardware perform tasks. Programs, operating systems, device drivers, and macros are all software. Contrast with hardware.

Solaris: The Sun workstation operating environment, including SunOS and the OpenWindows windowing environment.

Solid Color: A color that appears on a display when all pixels are the same color. On a monochrome display, there are only two solid colors: black and white. Contrast to nonsolid color or dithered color.

Source Code: A program in the form of an ASCII text file. Programs as they are written in a programming language, such as C and Pascal. In order to run the program, source code must be translated into machine code by either an interpreter or a compiler.

SPARC: the RISC CPU used in newer Sun workstations.

SPARCStation: A Sun workstation model using the SPARC CPU.

SPECmark: Systems Performance Evaluation Cooperative MARK. A suite of ten benchmarks that test integer (SPECint) and floating point (SPECfp) performance of a computer. A VAX-11\780 is a one-SPECmark machine.

Spool: To transfer data intended for a peripheral device (usually a printer) into temporary storage. From there the data can be transferred to the peripheral at a later time, without affecting or delaying the system as it performs other operations.

Standard Mode: In Windows. An operating mode that provides access to extended memory and also enables you to switch between non-Windows applications, but it does not provide virtual memory or enable non-Windows applications to run in the background or in a window. Hint: You can tell what mode your copy of Windows is running in by choosing About Program Manager... from the Help menu in the Program Manager.

Startup Disk: Also called a system disk. A disk that contains files necessary to start up a computer. A Macintosh startup disk must contain a System file and the Finder file. An MS-DOS startup disk must have the invisible system files (IO.SYS and MSDOS.SYS) and a COMMAND.COM file. You should have an extra system disk around in case the system files on the hard drive that starts your computer are damaged. Without a system disk, you will not be able to access and fix your hard disk.

Subdirectory: A directory within another directory.

Submenu: Also called a hierarchical menu or submenu. A secondary menu that appears while dragging and holding over an item in a menu. It gives you choices of options that apply to the item you are selecting in the menu.

Subnets: logical divisions of a network into smaller subnetworks. Created using routers or gateways on networks with high traffic. Gives better adminstrative control and improves performance.

Subnotebook: A portable computer, smaller than a notebook, usually weighing less than 5 pounds. Subnotebooks often have fewer ports than a notebook, and no internal floppy drive.

Sun: Sun Microsystems. Makers of high-end UNIX workstations.

SunOS: A version of UNIX produced by Sun Microsystems for their Sun workstations.

SuperDrive: A floppy disk drive in Macintosh computers that enables it to read 400K, 800K, and 1.44MB disks. Also allows you (with proper software) to read MS-DOS disks.

SuperVGA: Super Video Graphics Array. Specifications for video output that expanded the VGA specifications on IBM PC and compatible computers to more than 640x480 resolution, and more than 256 colors. There is not a single SuperVGA standard, so not all SuperVGA devices have compatible features.

Surge Suppressor: An electrical device that electronic equipment can be plugged into. A surge suppressor includes a circuit breaker that will protect equipment from damage from a surge in electricity (from, e.g., a lightning strike).

Swap File: An area of your hard disk that is set aside for virtual memory. Swap files can be either temporary or permanent.

System: 1) An essential file (program) which makes up part of the MacOS. The system file controls the basic operation of the computer at a low-level, such as printing, saving, etc. 2) A generic term for an operating system.

System 7: The current generation of the Macintosh operating system. There are several versions of System 7, such as 7.0, 7.1, 7.5, 7.5.2, and 7.5.3.

System Disk: See Startup Disk

System File: On an MS-DOS system, a file that contains information required for running the MS-DOS operating system. A system file is hidden, that is, it is not shown in the directory listing (unless you use the /a option).

System Software: The programs which are necessary to run the computer. The system software provides the interface to the computer and controls basic operations like saving and printing.

SYSTEM.INI file: A Windows initialization file that contains settings you can use to customize Windows for your system's hardware. It can be edited manually, but this should only be attempted if you know what you are doing. Even then, you should be sure to have a backup copy.

Task List: In Windows, a window that shows a list of all of the applications currently running. It enables you to switch between them. On Macintosh System 7, the Application menu (the icon at the far right of the menu bar) performs a similar function.

TCP/IP: Transmission Control Protocol/Internet Protocol. The networking protocols used on the internet.

Terminate-and-Stay-Resident Program: See TSR.

Text Editor: An application used to create, view, and modify text files. For example, Notepad in Windows, Edit in MS-DOS, SimpleText on the Macintosh, or VI on Unix. Text editors do not support the formatting functions of word processors.

Text File: See ASCII Text File.

Text Mode: In MS-DOS, the mode that enables applications to display text but not graphic images.

Thick Ethernet: Ethernet cabling which uses half inch diameter coaxial cable to connect computers. The connector, DB-9, resembles a serial port.

Thin Ethernet: Ethernet cabling which uses thin coaxial cable to connect computers. Uses a T-shaped connector.

Tile: In Windows. A way of arranging open windows so that no windows overlap but all windows are visible. Each window takes up a portion of the screen.

Title Bar: Area at the top of a window which indicates the name of that window. In most GUIs, the title bar is dragged to move the window. Title bars, in most GUIs, have an area to click on to close the window as well as an area that will resize it if clicked.

Token Ring: A networking hardware system developed by IBM. Constructed as a ring of daisy chained nodes. Each node passes a control message (token) around the ring. Whichever node has the token can send a message.

Topology: The physical layout of network cabling.

TrueType Fonts: Fonts that are scaleable and sometimes generated as bitmaps or soft fonts, depending on the capabilities of your printer. TrueType fonts can be sized to any height, and they print out exactly as they appear on the screen.

TSR: Terminate-and-Stay-Resident Program. Also called memory resident or pop-up program. An MS-DOS program that is loaded into memory and is available even as another application is active.

Twisted Pair Wire: Commonly used for telephone and network wiring. Twisted pair consists of two pairs of wires- one for transmitting and one for receiving data. The wires in each pair are twisted together to reduce induction between them. 10Base-T Ethernet cable is twisted pair.

UAE: Unrecoverable Application Error. Occured often in Windows 3.0 and below. UAEs would bring the entire machine down causing loss of data. Windows 3.1 greatly improved the handling of UAEs. While UAEs still occur (much less that previously), they crash only that application and not Windows or the entire machine.

UNIX: An operating system developed by AT&T in 1972; it features multiuser support, pre-emptive multitasking, and strong networking capabilities. Many versions of UNIX, and UNIX-like clones, have been produced through the years, including System V, BSD, NetBSD, Linux, AIX, A/UX, MINIX, SunOS, etc.

Upper Memory Area: On IBM PC and compatible computers. The 384K area of address space adjacent to the 640K of conventional memory (these two total 1 Megabyte). This area is usually reserved for running your system's hardware, such as your monitor, and is not considered part of total memory because applications cannot store information in this area. In 386 enhanced mode, Windows can access unused portions of this area. Some memory managers also allow applications access to unused portions of this area.

Upper Memory Blocks: On IBM PC and compatible computers. Areas of the upper memory area that contain general-purpose memory and that can be used to hold device drivers or other memory-resident programs in order to leave more conventional memory available for applications.

UPS: Uninterruptible Power Supply. A backup power unit that provides continuous power when the normal power supply is interrupted. UPS systems can be stand-by, only supplying power when the regular supply is interrupted, or fulltime, relying on regular power and/or batteries to supply it while it supplies power to the protected device. A UPS is not necessary on most computer systems, but can be important on systems that need to be up 24 hours a day, such as servers.

URL: Uniform resource locator. Used with the WWW to identify the type and location of a multimedia resource on the internet. For example, the URL <FTP:< STRONG>//mirrors.aol.com/pub/info-mac/help/faq-of-faqs.txt> identifies a file named faq-of-faqs.txt, available via ftp, located on the site mirrors.aol.com, in the directory /pub/info-mac/help/.

Usenet: A collection of discussion areas available via the internet. Usenet provides a large number of "newsgroups" that discuss a wide variety of topics, including technical computer, scientific, recreational, and social areas. Usenet can be accessed with a number of programs on different computer platforms.

User Interface: The aspect of a computer or program that is visible to the user, giving and accepting information from him or her. User interfaces are, broadly, CLIs and GUIs.

Utility: A program intended to make the use of a computer or of an application program easier.

UUCP: UNIX-to-UNIX Copy Protocol. Networking software used to transmit data over phone lines. UUCP is not used much now.

UUencode/UUdecode: A system for encoding binary files as ascii files for easy transfer between computer systems. Widely used on Unix systems.

V.DOT terms: A series of modem communications standards:

V.32: Supports standard 9600 bps.

V.32bis: Supports 14.4K bps.

V.42: Supports error detection and data compression.

V.42bis: Supports a different data compression scheme than V.42.

V.34: Supports 28.8K bps.

VGA: Video Graphics Array. Specifications for video output on IBM PC and compatible computers, which features 640x480 resolution and 256 colors (8 bit graphics).

Virtual Drive: See RAM disk.

Virtual Memory: Method of using hard disk space to provide extra memory. Simulates additional RAM. In Windows, the amount of virtual memory available equals the amount of free RAM plus the amount of disk space allocated to the swap file. In Macintosh System 7, virtual memory is controlled in the Memory Control Panel. The default setting is twice the amount of RAM in the machine. However, the amount of RAM plus the amount of virtual memory TOGETHER is the amount of disk space you must allocate. For example, if you have 4 MB of RAM and set virtual memory at 8 MB, 12 MB of disk space is allocated.

Virtual Reality (VR): An emerging technology that attempts to fully immerse the user in an interactive computer generated environment. VR is rather ill-defined, but focuses on a more complex interaction with the computer, featuring at least 3D interactive video.

VRML: Virtual Reality Modeling Language (originally, Virtual Reality Markup Language). An evolving language specification to provide virtual reality resources on the internet. Currently, VRML provides support for interactive 3D graphics data.

WAIS: Wide Area Information Server. An information retrieval system used on the internet, which features text search facilities to identify the documents that the user wants to find.

WAN: Wide Area Network. A network linking computers, terminals, and other equipment over a large geographic area.

Web: See World Wide Web.

Web Browser: A program that accesses the WWW, allowing the user to use the multimedia resources of the internet. A web browser will require internet access (either ethernet hardware or PPP/SLIP), and sufficient graphics hardware.

Wildcard: A character that can be used to represent any other character or series of characters in a statement. For instance, the wildcard "*" allows "DAN*Y" to refer to both "DANNY" and "DANDY." Useful in searches when you don't know the exact text you are looking for, and in specifying and action to be performed on a group of files.

WIN.INI file: A Windows initialization file that contains settings you can use to customize your Windows environment. It can be edited manually, but this should only be attempted if you know what you are doing. Even then, you should be sure to have a backup copy.

Window: A rectangular area on the screen, showing a section of a program or document. You can open, close, and move windows, and change the size of most windows.

Windows: Operating Environment written by Microsoft. It is a Graphical User Interface that runs on top of MS-DOS.

Windows 3.11: The last release of the Microsoft Winows Operating Environment before Windows 95.

Windows 95: The latest release of the Microsoft Windows Operating Environment. Windows 95 features full 32 bit design, pre-emptive multitasking, and multithreading. Windows 95 is a successor to Windows 3.1 and Windows for Workgroups, but it does not replace Windows NT.

Windows NT: An operating system developed by Microsoft, designed to provide networking services, and to be at least somewhat processor independent. NT shares a common interface with Windows 3.1, but does not require MS-DOS. NT runs on Intel processors (386 and above), MIPS, and the DEC Alpha. Support for the PowerPC is planned.

Word Processor: Application which provides you with the tools necessary to create and edit and format text. Word processors commonly include an area to enter text, the ability to control the format of text (bold, italics, size), indenting, margins, the ability to check spelling, etc. Many word processors also handle graphics to a varying degree.

Word Wrap: A feature that moves text from the end of a line to the beginning of a new line as you type. With word wrap, you do not need to press ENTER at the end of each line in a paragraph.

Workspace: The area of a window that displays the information contained in the application or document you are working with.

Workstation: A class of desktop machine, conventionally considered more powerful than a personal computer (or microcomputer). As personal computers have continued to become more powerful, the distinction between personal computers and lower end workstations has blurred.

World Wide Web (WWW): An amalgam of internet sites offering text, graphics, sound, and animation resources in an easy to use way, through the