R

This page coded by Adam Ankiewicz, Desert Rose Adult High School, March, 2007

r Services
Refers to a class of remote tools in Unix systems.

Race Condition, Race Hazard
In digital circuit design, a situation where two signals are "racing" to the same component but different places, and although intended to be simultaneous, they do not arrive at exactly the same time. Thus, for a brief moment, the component at the destination recieves an incorrect combination of inputs.

Radial Fill
A way of filling sa graphical object with two colors such that one color is at the center, and there is a smooth transition to another color at the edges.

Radian Measure
A way of measuring the size of angles in which a complete rotation measures 2pi radians. The trigonometric functions in most computer languages expect their arguments to be expressed in radians. To convert degrees into radians, multiply by pi/180 (approximately 1/57.296).

Radio Buttons
Small circles in a dialog box, only one of which can be chosen at any time. The chosen button is black and the others are white. Choosing any button with the mouse causes all other buttons in the set to be cleared. Radio buttons acquired their name because they work like buttons on older car radios. Also called Option Buttons.

Radio Frequency Interference (RFI)
Also known as electromagnetic interference. Electric circuits that carry rapidly changing signals, such as data lines, emit an electromagnetic signal. This signal can interfere with or disturb signals on other lines. This physical property can be abused by crackers (phreakers) to block or slow down the communication infrastructure of a target.

Radix
The base of a number system. Binary numbers have a radix of 2, and decimal numbers have a radix of 10.

Radix Sort
An algorithm that puts data in order by classifying each item immediately rather than comparing it to other items. For example, you might sort cards with names on them by putting all the A's in one bin, all the B's in another bin, and so on. You could then sort the contents of each bin the same way using the second letter of each name, and so on. The radix sort method can be used effectively with binary numbers since there are only two possible bins for the items to be placed.

Ragged Margin
A margin that has not been evened out by justification and at which the ends of words do not line up.
This is
an example of
flush-left, ragged-right type.

RAID (Redundant Array of Inexpensive Disks)
A highly reliable way of sorting data using a set of disk drives rather than just one. One type of RAID system divides up each byte of data into bits and stores each bit on a different disk. If the data consists of 8-bit bytes, there will be 10 disks, one for each of the 8 bits, two more for an error correcting code. The error correcting code makes it possible to reconstruct any single missing bit in any byte. Thus, if one of the disk drives fails completely, only one bit will be missing from each byte, and the contents of the failed disk can be reconstructed completely from the error correcting code. RAID also includes other ways of combining disk drives, including a simple scheme in which one drive stores a copy of the information on the other.

railroad diagram
A diagram illustrating the syntax of a programming language or document definition.

RAM (Random Access Memory)
A memory device whereby any location in memory can be found as quickly as any other location.

Rambus
A company headquartered in Los Altos, CA, whose best known product is a high speed memory interface used with the Pentium IV.

random-access device
Any memory device in which it is possible to find any particular record as quickly, on average, as any other record.

random-number generator
A computer program that calculates numbers that seem to have been chosen randomly.

raster
A scan pattern that fills the screen of a CRT.

raster graphics
Graphics in which an image is generated by scanning an entire screen or page and marking every point as black, white, or another color.

raster image processor
A device that handles computer output as a grid of dots.

rasterize
To convert an image into a bitmap of the right size and shape to match a raster graphics output device.

raw
Unprocessed.

ray tracing
The computation of the paths of rays of light refelcted and/or bent by various substances.

RCA plug
An inexpensive shielding plug sometimes used for audio and composite video signals.

RDRAM (Rambus dynamic random access memory)
A type of high speed ram commonly used with the Pentium IV, providing a bus speed on the order of 500 MHz.

read
To tranfer information from an external medium into a computer.

readme
The name given to files that the user of a piece of software is supposed to read before using it.

read-only
Pre-recorded an unabled to be changed.

read-only memory
Computer memory that is permanently recorded and cannot be changed.

Real Audio
A communications protocol developed by Real Networks that allows audio signals to be broadcast over the Internet.

real estate
Space on a flat surface of limited size, such as a motherboard, or even a computer screen.

real number
Any number that can be represented as an integer or a decimal fraction with any finite or infinite number of digits.

RealPlayer
A widely used program for playing RealAudio files, distributed by Real Networks.

real-time programming
programming in which the proper function of the program depends on the amount of time consumed.

ream
Five hundred sheets of paper.

reboot
Restart a computer.

rebuild Desktop
A house cleaning operation that needs to be performed monthly on Macintosh computers running Mac OS 9 or earlier.

record
A collection of related data items.

recovering erased files
Retrieval of deleted files whose space has not yet been overwritten by other data.

recovery
The act of restoring regular business operations as quickly as possible after a natural or man-made disaster.

recursion
The calling of a procedure by itself.

Recycle Bin
In Windows, the place where deleted files are stored.

Red Book
The Philips/Sony standard format for audio compact discs.

Red Box
When a coin is put into a payphone, the payphone emits tones to the ACTS (Automated Coin Toll System). A red box can fool the ACTS into believing that an individual actually put money into the phone simply by playing the ACTS tones into the telephone microphone.

Red Hat
A company headquartered in Ralieigh, NC (USA), which distributes a popular version of Linux.

Red Route
One registered with the Internet Routing Registry (IRR) and is configured to be proxied by the route servers but is not announced in a view. One of three categories of Internet route states defined by the Policy Analysis of Internet Service Providers) project, an initiative dedicated to the development of tools that ISPs, network operators, and end-users can use to troubleshoot Internet routing and policy problems.

Red Team
A military term that refers to a team of experts who focus on penetration testing, assessment, and the design of secure systems.

redirect
In HTML, an instruction to go directly to another webpage without requiring the user to click.

redline
To mark a portion of a printed document that has been changed.

redo
To reverse the effect of the most recent undo command.

redundancy
The provision of extra information or extra hardware to increase reliability.

reentrant procedure
A procedure that has been implemented in such a way that more than one process can execute it at the same time without conflict.

refactoring
The process of reorganizing a computer program without changing its functionality.

reflection
The ability of a computer program to obtain information about itself.

reflow
Rearrange a written test so that the ends of lines come out more even.

refresh
To update the contents of a window to show information that has changed.

refresh rate
The rate at which a video screen is repeatedly scanned to keep the image constantly visible.

regional settings
The settings in an operating system that pertain to the user's location, such as language, currency, and time zone.

register
1. A row of flip-flops used to store a group of binary digits while the computer is processing them.
2. To inform a manufacturer of a purchase.

registrar
An organization authorized to register TOP-LEVEL DOMAINS.

registration
1. The act of informaing the manufacturer of a product that you have purchased and installed it.

2. The recording of information in the Windows Registry or siilar configuration files.

Registry
The part of Windows that stores setup information for the hardware, software, and operating system.

regression test
Performed on a program after a change was performed to ensure that the modifications are correct and that the changes did not negatively affect the unchanged portions of the program.

regular expression
A way of defining a possible series of characters.

relational database
A databse that consists tables made up of rows and columns.

relative address
In computer memory, a memory address measured relative to another location.

relative URL
A URL for a document in the same directory as the current document.

release
The edition or version number of a software product.

reload
To obtain a fresh copy of information that is already in a computer.

Remanence or Magnetic Remanence
The information that stays behind after storage media are erased.

remote
Located on a computer far away from the user.

Remote Access
A service allowing users to connect to their local network by telephone.

Remote Adminstration Trojans(RATs)
Malicious code appearing to be harmless or to be doing proper applications. RATs let a cracker get unrestricted access to another person's computer when that person is online.

Remote Attacks
An attack on a computer that may occur from anywhere.

Remote Authentication Dial-In User Service (RADIUS)
A network protocol enabling remote access to talk with a central server to authenticate dial-in users and grant access to the computer system or service.

Remote Data Objects (RDO)
An application program interface (API) from Microsoft Corporation permitting individuals writing Windows applications to get access to the database.

Remote Desktop
A feature of Microsoft Windows (2000 and up) that allows one computer to serve as the screen, keyboard, and mous of another; thus, any computer can be operated remotely.

Remote Service Crash
Caused by a fault in the particular service or daemon software that causes the service to terminate. Initiated or caused over the network.

Remote System Crash
Caused by a fault in networking components in the operating system software that makes it stop working properly, if at all.

remoting
The spreading of a computational task across multiple computers in different locations.

remove spots
A photopaint filter that erases spots from digitized photographs and pictures.