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Glossary
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radio button. A type of mouse-clickable button in a graphical user interface. Radio buttons are grouped together and only one of the group can be "on" at a time. The name comes from the type of buttons that used to be on car radios; when you press a button to select a station, the other buttons all pop out. The same logic is applied to radio buttons, which are used to select only one of a group of options at a time.
RAM. Acronym for Random-Access Memory. The computer's main memory where programs and data are stored (they can be written to and read from) while the program is running. Information stored in RAM is lost when the computer is turned off.
random access. The ability to access any piece of information from a storage medium, such as a disk or RAM. The idea here is that random access gives you the ability to access any information without having to read everything the comes before it.
RAS. An acronym for Remote access service. Now known as Dial-Up Networking (DUN), provides remote access to networks. DUN allows a remote user to access his network. Once connected, it is as if the remote computer is logically on the network; the user can do anything that he could do when physically connected to the network.
raster. A frame or pattern that an electron beam sends to the screen on your monitor. Scan patterns are sent to the screen continuously, a line at a time, to create the images and motion you see. The patterns displayed on the screen are sent using an electron "gun" that wipes the inside of your monitor like a firefighter's hose. The patters are sent from top to bottom and each new pattern is sent before the last one is finished. This creates "bands" of images called raster images.
read. The act of transferring data from a storage medium to the internal RAM of a computer.
read-only. A type of medium from which you can read data but to which you cannot write data.
real time. A measurement of time based on actual time elapsed, rather than computer-time units. Read-time computer events can be measured with normal time-telling equipment. Many computer operations measure elapsed time based on computer processing time or other non-real systems, or they can simulate faster-than-normal or slower-than-normal time for experiments.
real-time clock. A computerized clock or timing device that tracks accurate time.
reboot. To restart the computer. Starting the computer is called "booting" or "booting up." There are two ways to reboot the computer: you perform a cold boot by switching the computer off, waiting, and then turning it back on again. You perform a warm boot by pressing Ctrl-Alt-Del on a PC or by pushing a reset button. Usually a warm boot is all that's required, but occasionally a cold boot is necessary to clear memory completely.
registry. A database within the Windows 95 and NT operating systems that contains information about your computer and its configuration.
relational database.
remote. A remote computer is one that is connected to your network from a distant location. Remote access means you are using a computer that is not within arm's reach.
removable disk. Any disk that can be removed from its drive or from the computer. However, the term is generally used to describe a type of high-capacity disk (such as a hard disk) that can be inserted and removed from its drive, as in a Bernoulli disk drive. Another term for the unremoveable disk is fixed disk, which means the disk is solidly attached to the computer.
reset. To restart the computer or restore previous settings. Reset is also a key on some Macintosh keyboards that performs a warm boot when you press it.
resolution. A way of measuring the clarity of an image. Resolution involves the number of elements per inch -- the number of pixels on you screen or dots your laser printer can produce which indicates how clear and sharp an image is.
restore. The act of copying files from an archive or set of backup disks or tape drive to their original locations on the hard drive.
RBG. Acronym for Red Green Blue. A type of color process that involves mixing intensities of red, green, and blue reflective colors. Based on the mixture and intensity of these colors, you can produce many of the colors in the normal spectrum.
RFC. Short for Request for Comments, a series of notes about the Internet, started in 1969 (when the Internet was the ARPANET). An RFC can be submitted by anyone. Eventually, if it gains enough interest, it may evolve into an Internet standard. Each RFC is designated by an RFC number. Once published, an RFC never changes. Modifications to an original RFC are assigned a new RFC number.
ROM. Read-Only Memory (ROM). ROM is any type of memory that can be read but not written to.
root directory. The first and often only directory on a disk. The root directory doesn't become important until you have subdirectories and a disk tree structure. Then the other directories -- the subdirectories -- branch from the root like a tree. In DOS, the symbol for the root directory is the single backslash (\).
RPC. Abbreviation of remote procedure call, a type of protocol that allows a program on one computer to execute a program on a server computer. Using RPC, a system developer need not develop specific procedures for the server. The client program sends a message to the server with appropriate arguments and the server returns a message containing the results of the program executed. Sun Microsystems developed the first widely used RPC protocol as part of their Open Network Computing (ONC) architecture in the early 1980s. The specification has been handed off to the Internet Engineering Task Force (IETF) as a step toward making ONC RPC an Internet standard. Two newer object-oriented methods for programs to communicate with each other, CORBA and DCOM, provide the same types of capabilities as traditional RPCs.
RosettaNet. Named after the ancient Rosetta stone, which helped decipher hieroglyphics. A non-profit organization (www.rosettanet.org) that seeks to implement standards for supply-chain (manager-supplier) transactions on the Internet. Created in Winter 1998, the group includes companies like American Express, Microsoft, Netscape, and IBM, and is working to standardize labels for elements like product descriptions, part numbers, pricing data, and inventory status. The group hopes to implement many of its goals through XML, a mark-up language that lets programmers classify information with tags.
RS-232. Abbreviation for Recommended Standard-232, also known as RS-232C. It is a standard method of transmitting data across serial cables and is used by modems, printers,and other serial devices
.RTF. A type of document file format, usually readable by most
major word processors. The Rich Text Format (RTF) file is basically a
text file. However, included in the text are various instructions that
describe the document's formatting.
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