MICROSOFT Computer Dictionary, Fifth Edition

Microsoft Computer Dictionary, Fifth Edition

n. A computer and/or a software system that reacts to events before the events become obsolete. For example, airline collision avoidance systems must process radar input, detect a possible collision, and warn air traffic controllers or pilots while they still have time to react.

RealVideo

n. The streaming technology developed by RealNetworks, Inc., for distributing video over intranets and the Internet. RealVideo transmits video from a server in encoded (compressed) form. The video and accompanying sound are viewed on the client end with the help of a software player. RealVideo works with both IP and IP multicasting and, as with RealAudio, does not require transmission of complete files before playback can begin. See also RealAudio, RealPlayer, streaming.

reboot

vb. To restart a computer by reloading the operating system. See also boot2, cold boot, warm boot.

receipt notification

n. An e-mail feature providing feedback to the sender that a message has been received by the recipient.

receive

vb. To accept data from an external communications system, such as a local area network (LAN) or a telephone line, and store the data as a file.

Receive Data n. See RXD.

rec. newsgroups

n. Usenet newsgroups that are part of the rec. hierarchy and whose names have the prefix rec. These newsgroups cover topics devoted to discussions of recreational activities, hobbies, and the arts. See also newsgroup, traditional newsgroup hierarchy, Usenet. Compare comp. newsgroups, misc. newsgroups, news. newsgroups, sci. newsgroups, soc. newsgroups, talk. newsgroups.

recompile

vb. To compile a program again, usually because of changes that needed to be made in the source code in response to error messages generated by the compiler. See also compile.

record1

n. A data structure that is a collection of fields (elements), each with its own name and type. Unlike an array, whose elements all represent the same type of information and are accessed using an index, the elements of a record represent different types of information and are accessed by name. A record can be accessed as a collective unit of elements, or the elements can be accessed individually. See also array, data structure, type1 (definition 1).

record2

vb. To retain information, usually in a file.

record format

n. See record structure.

record head

n. The device in a tape machine that places data on the tape. In some tape machines, the record head is combined with the read head.

record layout

n. The organization of data fields within a record. See also record1.

Microsoft Computer Dictionary, Fifth Edition

record length

n. The amount of storage space required to contain a record, typically given in bytes. See also record1.

record locking

n. A strategy employed in distributed processing and other multiuser situations to prevent more than one user at a time from writing data to a record. See also record1.

record number

n. A unique number assigned to a record in a database in order to identify it. A record number can identify an existing record by its position (for example, the tenth record from the beginning of a database), or it can be assigned to the record to serve as a key (for example, the number 00742 assigned to the tenth record from the beginning of the database). See also record1.

record structure

n. An ordered list of the fields that compose a record, together with a definition of the domain (acceptable values) of each field. See also record1.

recover

vb. 1. To return to a stable condition after some error has occurred. A program recovers from an error by stabilizing itself and resuming execution of instructions without user intervention. 2. To put back into a stable condition. A computer user may be able to recover lost or damaged data by using a program to search for and salvage whatever information remains in storage. A database may be recovered by restoring its integrity after some problem has damaged it, such as abnormal termination of the database management program.

recoverable error

n. An error that can be successfully managed by software. For example, when the user enters a number when a letter is required, the program can simply display an error message and prompt the user again.

recovery

n. The restoration of lost data or the reconciliation of conflicting or erroneous data after a system failure. Recovery is often achieved using a disk or tape backup and system logs. See also backup.

Recreational Software Advisory Council

n. An independent, nonprofit organization established in the fall of 1994 by a group of six trade organizations, led by the Software Publishers Association. The Council’s goal was to create a new, objective content-labeling rating system for recreational software and other media such as the Internet. Acronym: RSAC.

rectangle ad

n. An Internet ad format that is larger than a traditional banner ad and is generally inserted directly into page content for greater visibility.

rectifier

n. A circuit component that passes current flowing in one direction but stops current flowing in the other direction. Rectifiers are used to convert alternating current to direct current.

recto

n. The right-hand page of two facing pages. A recto is characteristically an odd-numbered page. Compare verso.

recursion

Microsoft Computer Dictionary, Fifth Edition

n. The ability of a routine to call itself. Recursion enables certain algorithms to be implemented with small, simple routines, but it does not guarantee speed or efficiency. Erroneous use of recursion can cause a program to run out of stack space during execution, causing the program, and sometimes the entire system, to crash. See also call1 (definition 2), routine.

Recycle Bin

n. A folder in Windows 9x, Windows CE, Windows NT, Windows 2000, and Windows XP represented by an icon on the screen resembling a basket decorated with the recycling logo. To remove a file, the user drags its icon to the Recycle Bin. However, a file in the Recycle Bin is not actually deleted from the disk until the user opens the Recycle Bin, selects the file, and presses the Delete key; until then, the user can retrieve it. Compare Trash.

Red Book

n. 1. The standards documents of the U.S. National Security Agency entitled “Trusted Network Interpretation of the Trusted Computer System Evaluation Criteria (NCSC-TG-005)” and “Trusted Network Interpretation (NCS-TG-011).” These documents define a system of ratings from A1 (most secure) to D (nonsecure), indicating the ability of a computer network to protect sensitive information. Compare Orange Book (definition 1). 2. A specifications book written by the Sony Corporation and Philips Corporation and endorsed by ISO, covering audio compact discs. Compare Green Book, Orange Book (definition 2). 3. Telecommunications standards published by the CCITT.

red-green-blue n. See RGB.

redirection

n. The process of writing to or reading from a file or device different from the one that would normally be the target or the source. For example, the MS-DOS or OS/2 command dir >prn redirects a directory listing from the screen to the printer. Compare pipe.

redirector

n. Software on a client computer that intercepts requests for information and, when appropriate, directs them to the network. Redirectors can either be built into the client operating system or be part of an added networking package.

redlining

n. A feature of a word processing application that marks changes, additions, or deletions made to a document by a coauthor or editor. The purpose of redlining is to produce a record of the changes made to a document during the course of its development.

redraw

n. See refresh (definition 1).

reduce

vb. In a graphical user interface, to decrease the size of a window. A user can reduce a window either by clicking the appropriate button in the title bar or by clicking the mouse on the border of the window and dragging the border toward the middle of the window. See also maximize, minimize.

Reduced Instruction Set Computing n. See RISC.

redundancy

n. Using one or more servers on a Web site to perform identical tasks. If one of the servers crashes, another server assumes its tasks. Redundancy ensures that the Web site will continue to function if one of the servers stops working.

Microsoft Computer Dictionary, Fifth Edition

redundancy check n. See CRC, LRC.

redundant code

n. Code that duplicates a function performed elsewhere—for example, code to sort a list that has already been sorted.

reengineer

vb. To rethink and redefine processes and procedures. In the context of computer systems, to reengineer means to change the way work is done in order to maximize the benefits of new technology.

reengineering

vb. 1. With regard to software, changing existing software to strengthen desirable characteristics and remove weaknesses. 2. With regard to corporate management, using information technology principles to address the challenges posed by a global economy and to consolidate management of a rapidly expanding work force.

reentrant code

n. Code written so that it can be shared by several programs at the same time. When a program is executing reentrant code, another program can interrupt the execution and can then start or continue execution of that same code. Many operating-system routines are written to be reentrant so that only one copy needs to reside in memory to serve all executing applications. See also relocatable code.

refactoring

n. An optimization process in object-oriented programming intended to improve the design or structure of a program without changing its functionality. The goal of refactoring is to make the program clearer and easier to work with—in part by removing duplication, abstracting common behaviors, and refining class hierarchies—and to improve the extensibility and reusability of existing code.

reference1

n. A data type in the C++ programming language. A reference must be initialized with a variable name. The reference then becomes an alias for that variable but actually stores the address of the variable.

reference2

vb. To access a variable, such as an element in an array or a field in a record.

reference parameter

n. A parameter in which the address of a variable, rather than the explicit value, is passed to the called routine. See also parameter.

reference type

n. A data type that is represented by a reference (similar to a pointer) to the type’s actual value. If a reference type is assigned to a variable, that variable references (or “points to”) the original value. No copy is made. Reference types comprise classes, interfaces, delegates, and boxed value types. See also data type, value type.

reflecting software n. See reflector.

reflective liquid-crystal display

Microsoft Computer Dictionary, Fifth Edition

n. A liquid crystal display that is not equipped with edge light or backlight to enhance readability but rather depends on reflecting ambient light, making it difficult to read in brightly lit environments such as the outdoors. Also called: reflective LCD.

reflective routing

n. In wide area networks, the process of using a reflector to distribute data, thereby reducing the load of the network server. See also reflector.

reflector

n. A program that sends messages to a number of users upon receipt of a signal from a single user. A common type of reflector is an e-mail reflector, which forwards any e-mail sent to it to the multiple recipients currently on its list. See also multiple recipients. Compare mail reflector.

reformat

vb. 1. In applications, to change the look of a document by altering stylistic details, such as font, layout, indention, and alignment. 2. In data storage, to prepare for reuse a disk that already contains programs or data, effectively destroying the existing contents.

refresh

vb. 1. To retrace a video screen at frequent intervals, even if the image does not change, so as to keep the phosphors irradiated. 2. To recharge dynamic random access memory chips (DRAMs) so that they continue to retain the information stored in them. Circuitry on the memory board automatically performs this function. See also refresh cycle.

refreshable

adj. In programming, referring to a program module capable of being replaced in memory without affecting processing of the program or the information being used by the program.

refresh cycle

n. The process in which controller circuitry provides repeated electric pulses to dynamic random access memory chips in order to renew the stored electric charges in those locations that contain binary 1. Each pulse is one refresh cycle. Without constant refreshing, dynamic semiconductor RAM loses any information stored in it—as it does when the computer is turned off or when the power fails. See also dynamic RAM, static RAM.

refresh rate

n. In reference to video hardware, the frequency with which the entire screen is redrawn to maintain a constant, flicker-free image. On TV screens and raster-scan monitors, the electron beam that lights the phosphor coating on the inner surface of the screen typically refreshes the entire image area at a rate of about 60 hertz, or 60 times per second. Interlaced monitors, which redraw alternate lines during each sweep of the electron beam, actually refresh any particular line only 30 times per second. Because odd and even lines are refreshed on successive sweeps, however, the effective refresh rate is 60 times per second. See also refresh (definition 1).

REGEDIT

n. See Registry Editor.

regenerate

vb. See rewrite.

regeneration buffer n. See video buffer.

regenerator

n. See repeater.

Microsoft Computer Dictionary, Fifth Edition

region

n. 1. An area dedicated to or reserved for a particular purpose. 2. In video programming, a contiguous group of pixels that are treated as a unit. On the Apple Macintosh, for example, a region is an area in a grafPort that can be defined and manipulated as an entity. The visible working area within a window is an example of a region. See also grafPort.

region code

n. Codes on DVD movie titles and DVD-ROM drives that prevent playback of certain DVDs in certain geographical regions. Region codes are part of the DVD specification. See also CSS, DeCSS.

region fill

n. In computer graphics, the technique of filling a defined region on the screen with a selected color, pattern, or other attribute. See also region (definition 2).

register

n. A set of bits of high-speed memory within a microprocessor or other electronic device, used to hold data for a particular purpose. Each register in a central processing unit is referred to in assembly language programs by a name such as AX (the register that contains the results of arithmetic operations in an Intel 80x86 processor) or SP (the register that contains the memory address of the top of the stack in various processors).

registered file type

n. File types that are tracked by the system registry and are recognized by the programs you have installed on your computer. See also file type.

registration

n. The process of precisely aligning elements or superimposing layers in a document or a graphic so that everything will print in the correct relative position. See also registration marks.

registration marks

n. Marks placed on a page so that in printing, the elements or layers in a document can be arranged correctly with respect to each other. Each element to be assembled contains its own registration marks; when the marks are precisely superimposed, the elements are in the correct position. See the illustration.

Registration marks.

registry

n. A central hierarchical database in Windows 9x, Windows CE, Windows NT, and Windows 2000 used to store information necessary to configure the system for one or more users, applications, and hardware devices. The Registry contains information that Windows continually references during operation, such as profiles for each user, the applications installed on the computer and the types of documents each can create, property sheet settings for folders and application icons, what hardware exists on the system, and which ports are being used. The Registry replaces most of the text-based .ini files used in Windows 3. x and MS-DOS configuration files, such as AUTOEXEC.BAT and CONFIG.SYS. Although the Registry is common to the several Windows platforms, there are some differences among them. Also called: system registry. See also hierarchical database, .ini, input/output port, property sheet, Registry Editor.

Microsoft Computer Dictionary, Fifth Edition

Registry Editor

n. An application under Windows that allows the user to edit the entries in the registry. Acronym: REGEDIT. See also registry.

regression analysis

n. In statistics, an analysis of the degree to which variations in an independent variable affect a dependent variable (a variable whose value depends on the value of another variable). See also multiple regression.

regression testing

n. Complete retesting of a modified program, rather than a test of only the modified routines, to ensure that no errors have been introduced with the modifications.

relation

n. A structure composed of attributes (individual characteristics, such as name or address, corresponding to the columns in a table) and tuples (sets of attribute values describing particular entities, such as customers, corresponding to the rows in a table). Within a relation, tuples cannot be repeated; each must be unique. Further, tuples are unordered within a relation; interchanging two tuples does not change the relation. Finally, if relational theory is to be applicable, the domain of each attribute must be atomic— that is, a simple value, rather than a structure such as an array or a record. A relation in which the domains of all attributes are atomic is said to be normalized or in first normal form. See also normal form (definition 1).

relational algebra

n. A collection of rules and operators that permits relations (tables) to be manipulated. Relational algebra is usually described as having the following operators: SELECT, PROJECT, PRODUCT, UNION, INTERSECT, DIFFERENCE, JOIN (or INNER JOIN), and DIVIDE. In a relational database, relational algebra is used to develop procedures to build new relations based on the existing relations.

relational calculus

n. In database management, a nonprocedural method for manipulating relations (tables). There are two families of relational calculus: domain calculus and tuple calculus. The two families of relational calculus are mathematically equivalent to each other and to relational algebra. Using either family, one can formulate a description of a desired relation, based on the existing relations in the database.

relational database

n. A database or database management system that stores information in tables—rows and columns of data—and conducts searches by using data in specified columns of one table to find additional data in another table. In a relational database, the rows of a table represent records (collections of information about separate items) and the columns represent fields (particular attributes of a record). In conducting searches, a relational database matches information from a field in one table with information in a corresponding field of another table to produce a third table that combines requested data from both tables. For example, if one table contains the fields EMPLOYEE-ID, LAST-NAME, FIRST-NAME, and HIRE-DATE, and another contains the fields DEPT, EMPLOYEE-ID, and SALARY, a relational database can match the EMPLOYEE-ID fields in the two tables to find such information as the names of all employees earning a certain salary or the departments of all employees hired after a certain date. In other words, a relational database uses matching values in two tables to relate information in one to information in the other. Microcomputer database products typically are relational databases. Compare flat-file database, inverted-list database.

relational database management system n. See relational database.

Microsoft Computer Dictionary, Fifth Edition

relational expression

n. An expression that uses a relational operator such as “less than” or “greater than” to compare two or more expressions. A relational expression resolves to a Boolean (true/false) value. See also Boolean, relational operator.

relational model

n. A data model in which the data is organized in relations (tables). This is the model implemented in most modern database management systems.

relational operator

n. An operator that allows the programmer to compare two (or more) values or expressions. Typical relational operators are greater than (>), equal to (=), less than (<), not equal to (<>), greater than or equal to (>=), and less than or equal to (<=). See also relational expression.

relational structure

n. The record organization used in the implementation of a relational model.

relative address

n. A location, as in a computer’s memory, that is specified in terms of its distance (displacement or offset) from a starting point (base address). A relative address is typically computed by adding an offset to the base. In everyday terms, this is similar to creating the address 2001 Main Street, in which the base is the 2000 block of Main Street and the offset is 1, which specifies the first house from the beginning of the block. Also called: indirect address.

relative coordinates

n. Coordinates that are defined in terms of their distance from a given starting point, rather than from the origin (intersection of two axes). For example, from a starting point on the screen, a square defined by relative coordinates can be drawn as a series of lines, each representing a displacement in distance and direction from the end of the preceding point. The entire square can be redrawn at another location simply by changing the coordinates of the starting point rather than by recalculating the coordinates of each corner with reference to the origin. See the illustration. Compare absolute coordinates.

Relative coordinates.

relative movement

n. 1. Motion whose distance and direction are relative to a starting point. For example, when a mouse pointer is moved on the screen, the coordinates of its new position are relative to the previous location of the pointer. See also relative coordinates, relative pointing device. 2. In computer graphics and cinematography, the movement of one object in relation to another, such as the movement of horse A from the perspective of horse B on a racetrack.

relative path

Microsoft Computer Dictionary, Fifth Edition

n. A path that is implied by the current working directory. When a user enters a command that refers to a file, if the full pathname is not entered the current working directory becomes the relative path of the file referred to. Compare full path.

relative pointing device

n. A cursor-control device, such as a mouse or a trackball, in which the movement of an onscreen cursor is linked to the movement of the device but not to the position of the device. For example, if a user picks up a mouse and puts it down in a different location on a desk, the position of the on-screen cursor does not change because no movement (rolling) is detected. When the user rolls the mouse again, the cursor moves to reflect the mouse movement against the surface of the desk. Relative pointing devices differ from absolute pointing devices, such as graphics tablets, in which the device’s location within a defined area is always associated with a predefined on-screen position. See also relative coordinates, relative movement (definition 1). Compare absolute pointing device.

relative URL

n. Short for relative uniform resource locator. A form of URL in which the domain and some or all directory names are omitted, leaving only the document name and extension (and perhaps a partial list of directory names). The indicated file is found in a location relative to the pathname of the current document. Acronym: RELURL. See also file extension, URL.

RELAX NG

n. An XML schema language based on Tree Regular Expressions for XML (TREX) and Regular Language Description for XML (RELAX). RELAX NG supports XML namespaces, uses XML syntax, maintains the information set of the XML document, and provides unrestricted support for mixed or unordered content.

relay

n. A switch activated by an electrical signal. A relay allows another signal to be controlled without the need for human action to route the other signal to the control point, and it also allows a relatively low-power signal to control a high-power signal.

release1

n. 1. A particular version of a piece of software, most commonly associated with the most recent version (as in “the latest release”). Some companies use the term release as an integral part of the product name (as in Lotus 1-2-3 Release 2.2 ). 2. A version of a product that is available in general distribution. Compare alpha2, beta2.

release2

vb. 1. To relinquish control of a block of memory, a device, or another system resource to the operating system. 2. To formally make a product available to the marketplace.

reliability

n. The likelihood of a computer system or device continuing to function over a given period of time and under specified conditions. Reliability is measured by different performance indexes. For example, the reliability of a hard disk is often given as mean time between failures (MTBF): the average length of time the disk can be expected to function without failing. See also MTBF, MTTR.

reliability, availability, serviceability

n. Acronym: RAS. See high availability.

reload

vb. 1. To load a program into memory from a storage device again in order to run it, because the system has crashed or the program’s operation was otherwise interrupted. 2. To retrieve a new copy of the Web page currently visible in a Web browser.

Microsoft Computer Dictionary, Fifth Edition

relocatable address

n. In programming, an address that is to be adjusted to reflect the actual place in memory into which a program is loaded for execution. In “Get the byte located 12 bytes from this instruction,” the address is relocatable; in “Get the byte located at address 255,” the address is not relocatable. This convention is comparable to describing the “address” of a parked car as “level 2, row G” on one day and “level 5, row B” on another.

relocatable code

n. A program written in such a way that it can be loaded into any part of available memory rather than having to be placed in one specific location. In relocatable code, address references that depend on the program’s physical location in memory are calculated at run time so that program instructions can be carried out correctly. See also reentrant code.

relocate

n. To move programs and blocks of memory about within available space so as to use memory resources flexibly and efficiently. A relocatable program can be loaded by the operating system into any part of available memory rather than into only one specific area. A relocatable block of memory is a portion of memory that can be moved around by the operating system as required; for example, the system might collect several available, relocatable blocks of memory to form one larger block of the size requested for use by a program.

RELURL

n. See relative URL.

remailer

n. A service that will forward e-mail while concealing the e-mail address of the originator of the message. Remailers may be used by individuals who wish to retain their privacy or avoid unsolicited commercial e-mail (UCE). Remailers may also be used to hide the identities of individuals and businesses sending spam or malicious or fraudulent e-mail.

remark

n. See comment, REM statement.

remote

adj. Not in the immediate vicinity, as a computer or other device located in another place (room, building, or city) and accessible through some type of cable or communications link.

remote access

n. The use of a remote computer.

remote access server

n. A host on a LAN (local area network) that is equipped with modems to enable users to connect to the network over telephone lines. Acronym: RAS.

Remote Access Service

n. Windows software that allows a user to gain remote access to the network server via a modem. Acronym: RAS. See also remote access.

remote administration

n. The performance of system administration–related tasks via access from another machine in a network.

Remote Application Programming Interface

n. A Remote Procedure Call (RPC) mechanism that enables an application running on a desktop computer to make function calls on a Windows CE–based device. The desktop computer is