RAM
Random Access Memory. RAM is the most common type of computer memory, and it's where the computer stores system software, programs, and data you are currently using. It's formally called dynamic RAM (DRAM) because it's volatile, that is, the contents are lost when you turn off the computer (or crash). It's pronounced ram and measured in megabytes.

Raster
A synonym for grid. Sometimes used to refer to the grid of addressable positions in an output device.

Rel
Recorder element. The minimum distance between two recorded points (spots) in an imagesetter.

Remote system
Another computer on the Internet to which you connect. Interactions between computers are often described using the terms "local" and "remote" systems. The local system is your computer and the remote system is the other computer.

Res
A term used to define image resolution instead of ppi. Res 12 indicates 12 pixels per millimeter.

Resampling
An increase or reduction in the number of pixels in an imge, required to change its resolution without altering its size. See also down-sampling and interpolation.

Resolution
In general, this refers to how sharp and clear an image looks on screen or on paper, and how much detail you can see. It's usually determined by the number of dots (or pixels) per square inch (the more there are, the higher the resolution) and is used to describe printers, monitors, and scanners.

RFC
Request For Comments; technical note series which began in 1969 describing DARPA and Internet research and development, particularly in the areas of protocol design and internetworking. Not all (in fact very few) RFCs describe Internet standards, but all Internet standards are written up as RFCs.

RGB
Red, green, and blue are the primary colors of light perceived by the eye.

RIP
Routing Information Protocol used by Berkeley UNIX systems to exchange routing information among a set of computers attached to a network. RIP packets are sent and received by a program called routed.

ROGER
On-line catalog at UCSD for books and other material in the libraries at the University of California at San Diego.

ROM
Read-Only Memory. It's like software that's hard-wired into your computer - basic, permanent information that tells it things like how to load up the operating system when you turn it on.

Router
A special purpose computer that attaches to two or more networks and routes packets from one network to the other. A router uses network layer addresses (such as IP Addresses) to determine if packets should be sent from one network to another. Routers send packets to other routers until they arrive at their final destination.

rpi
Rels (recorder elements) per inch. A measurement of the number of discrete steps that exposure units in imagesetting devices can make per inch.

RS-232
Interface between Data Terminal Equipment (DTE) and Data Communications Equipment (DCE) employing Serial Binary Data Interchange, a standard set by the international standards organization - Consultative Committee on International Telegraphy and Telephony. The interface between a terminal to a modem for the transfer of serial data.

RTF
Rich Text Format. A file format for text files that includes formatting instructions. Also called Interchange Format.