R

RABBITS

Virus programs that rapidly reproduce themselves. See Bacteria.

RACK-MOUNT

Standard cabinets with 1.75" vertical spacing between mounting holes and 19" wide horizontal spacing between mounting rails.

RACS

Road-Automobile Communication System

RADIUS

Remote Dial-In User Services

RADIX (BASE)

The quantity of characters for use in each of the digital positions of a numbering system; the octal radix is 8; the decimal radix is 10; the hexadecimal radix is 16.

RAID

See Redundant Array of Inexpensive Drives.

RAID 0

Another name for RAID 4 with no parity. See RAID 4.

RAID 1

This level has duplicate disks operating side by side in parallel "disk mirroring". System reliability is very high. If one disk fails, the other can supply any data needed. However, only 50% of drive capacity is available for storage.

RAID 2

It is not used due to its incompatibility with current disk drives.

RAID 3

This level uses data striping and a dedicated parity drive. When data is written to the array, one byte goes to each disk. Each drive is accessed at the same time. The advantage is a very high transfer rate. The downside is that since every drive is used, only one I/O transaction can be processed at the same time. RAID 3 is best for large data requests.

RAID 4

Also called RAID 0. Blocks of data are striped across the array of disks, thus the disks can be accessed in parallel mode. Has a higher I/O rate than RAID 3, but data transfer is slower. Parity drives may be used to provide tolerance to data drive failure. RAID 4 with no parity is known as RAID 0.

RAID 5

Unlike RAID 3, which accesses all the drives at the same time for read and write, RAID 5 can access as many drives as possible at the same time for different reads or writes. As a result, RAID 5 offers the highest I/O transfer rate of all the RAID levels.

RAM START ADDRESS

See Base Memory Address.

RARE

See Reseaux Associes pour la Recherche Europeenne.

RARP

See Reverse Address Resolution Protocol.

RASTER

A scanning pattern. The area of a picture tube scanned by the electron beam. The pattern is usually from left-to-right and from top-to-bottom.

RASTER FONTS

A set of characters for screen display or printing that are stored as bitmaps in specific character sizes.

RASTER GRAPHICS

Images defined as a set of pixels or dots in a column-and-row format. Also called bit-mapped graphics.

RATP

Reliable Asynchronous Transfer Protocol

RAW SOCKETS

Provide access to the low-level protocol that supports sockets. This access to the underlying protocols makes raw sockets useful for development and testing. See also socket.

RBOC

See Regional Bell Operating Company. See BOC.

RC

IC part number prefix indicating Raytheon Semiconductor.

RC

Routing Control

RD

Route Descriptor

RDA

The RS-422-A data input to the device.

RDA

Remote Data Access

RDB

The differential return signal for RDA. See RDA.

RDBMS

See Relational Data Base Management Systems.

RDP

Reliable Data Protocol

READ OPERATION

Any operation in which information is read from a disk. DOS commands that perform read operations include dir (directory listing), type (display contents of a file), and copy (copy files). See also Write Operation.

README

A file included in a software package to document very recent information. It supplements formal product documentation and ensures that information is up-to-date when a product is shipped to users.

REAL-TIME

In computing, refers to an operating mode under which data is received and processed and the results returned so quickly as to seem instantaneous.

REBOOT

To restart a computer. In host systems, this is frequently called an IPL or an IML. See IPL.

REDIRECTED DRIVE

A LAN feature allowing one LAN-attached workstation to access a drive on another LAN-attached workstation using a simple drive designation uniquely equated to the target workstation's drive.

REDUCED INSTRUCTION SET COMPUTER

(RISC) A type of processor architecture that minimizes the number of instructions performed by the processor to increase processing speed, such as the Power PC chips - Motorola 903, etc. Contrast with CISC.

REDUNDANT ARRAY OF INEXPENSIVE DRIVES

(RAID) A disk subsystem that contains multiple disk drives in which data is spanned across drives for the purpose of performance or fault tolerance. RAID subsystems have several different types of configurations, but RAID 5 is most commonly used for protection of data with good performance. See RAID 1, 2, 3, 4, and 5.

REFERENCE

Each Usenet news article contains a computer generated reference message-Id which makes an article unique. This identifier looks something like <1993Jan21.214833.25109@titan.ksc.nasa.gov>. Identifiers may appear a number of times in an article when someone quotes or references another article.

REGIONAL BELL OPERATING COMPANY

(RBOC) One of seven regional telephone companies created by the AT&T divestiture: Nynex, Bell Atlantic, Bell South, Southwestern Bell, US West, Pacific Telesis and Ameritech.

REGISTRATION DATABASE

The REG.DAT file, which provides the information used by File Manager and Print Manager to support drag-and-drop and other actions, and which is used by OLE applications to find file types and OLE capabilities for embedded objects.

RELATIONAL DATA BASE MANAGEMENT SYSTEMS

(RDBMS) Any application designed to manage multiple tables of data and allow users to establish relationships among columns of data.

RELATIONAL DATABASE

1. A database organized and accessed according to relationships between data items. 2. A data structure perceived by its users as a collection of tables. It consists of tables, rows, and columns. Relational databases differ from nonrelational databases in that there are no system dependencies stored within the data. Hierarchical databases are not relational, because they contain pointers to other data.

RELIABLE CONNECTION

A connection between two modems where they communicate using an error control protocol (such as LAPM or MNP).

RELIABLE TRANSFER SERVICE AGENT

(RTSE) A lightweight OSI application service used above X.25 networks to handshake application PDUs across the Session Service and TP0. Not needed with TP4, and not recommended for use in the U.S. except when talking to X.400 ADMDs.

REM

Ring Error Monitor

REMOTE BOOT CHIP

A chip installed on a NIC or diskless workstation that enables the workstation to boot from a boot image file on the server, without the aid of a local disk drive.

REMOTE FILE SYSTEM

(RFS) A distributed file system, similar to NFS, developed by AT&T and distributed with their UNIX System V operating system. See NFS.

REMOTE OPERATIONS SERVICE ELEMENT

(ROSE) A lightweight RPC protocol, used in OSI Message Handling, Directory, and Network Management application protocols.

REMOTE PROCEDURE CALL

(RPC) An easy and popular paradigm for implementing the client-server model of distributed computing. A request is sent to a remote system to execute a designated procedure, using arguments supplied, and the result returned to the caller. There are many variations and subtleties, resulting in a variety of different RPC protocols.

REMOTE-TO-LAN

A LAN Distance environment in which a standalone workstation connects to a LAN and accesses its workstations and resources. The standalone workstation connects to the LAN by dialing a LAN Distance Connection Server workstation on the LAN. See also Dial-In.

REMOTE-TO-REMOTE

A LAN Distance environment in which two workstations are connected to form a LAN Distance wide area network. Each workstation can access the other's resources and LAN applications over the LAN Distance connection. See also virtual LAN.

REPEATER

A device that repeats or amplifies bits of data received at one port and sends each bit to another port. A repeater is a simple bus network device that connects two cabling segments and isolates electrical problems to either side. When used in a LAN, most repeaters take a role in reconstituting the digital signal that passes through them to extend distances a signal can travel, and reduce problems that occur over lengths of cable, such as attenuation. A repeater functions at the physical layer. It indiscriminately passes all signals from one segment to another. The media type must be the same (for example, Ethernet to Ethernet). Equipment that is inserted at some point along the transmission line to amplify the signal. Repeaters are often used to "boost" a signal traveling over long distances, as in the case of lines that fail the local loop qualification test. It reconditions each signal to extend the distance between two hosts beyond the maximum segment length for any particular hardware. In OSI terminology, a repeater is a Physical Layer intermediate system. See also LOOP QUAL, LOCAL LOOP, bridge and router.

REQUEST FOR COMMENT

(RFC) Many Request for Comments are available online. Paper copies of all RFCs are available from the NIC (for more information contact NIC@NIC.DDN.MIL). Online copies are available via FTP or Kermit from NIC.DDN.MIL as RFC:RFC####.TXT or RFC:RFC####.PS (#### is the RFC number without leading zeroes). Additionally, RFCs may be requested through electronic mail from the automated NIC mail server by sending a message to SERVICE@NIC.DDN.MIL with a subject line of "RFC ####" for text versions or a subject line of "RFC ####.PS" for PostScript versions. To obtain the RFC index, the subject line of your message should read "RFC index." RFC Index.

REQUEST TO SEND

See RTS

RESEAUX ASSOCIES POUR LA RECHERCHE EUROPEENE

(RARE) European association of research networks.

RESEAUX IP EUROPEENNE

(RIPE) European continental TCP/IP network operated by EUnet. See EUnet.

RESERVED MEMORY:

Reserved Memory is the address space between 640Kb and 1 Mb and was designed to be reserved for system operations. The system BIOS ROM, video ROM, and ROMs of some add-in cards reside in the reserved memory address space. Keep in mind that this is "address space", meaning that there doesn't have to be any physical memory located at all the addresses from 640K to 1 megabyte. The system BIOS ROM can be found at hex address F0000 or 960K. If you have a VGA or EGA video card you can almost always find video ROM at hex address C0000 or 768K. Between the video ROM and the system BIOS ROM at hex address D0000 for example, there might not be anything at all. This "address space" is unused and available, and drivers such as Intel's EMM.SYS (Expanded Memory Manager) can "map" blocks of memory within the C000-DFFF address range (between 768K and 896K), which means that the memory EMM.SYS controls on an Intel memory board will appear within that address range.

RESOLUTION

The number of pixels per unit of area. A display with a finer grid contains more pixels and has a higher resolution, capable of reproducing more detail in an image.

RESOURCE

1. Any facility of a computing system or operating system required by a job or task, including memory, input/output devices, processing unit, data files, and control or processing programs. 2. A network component such as a file, printer, or serial device that is shared by other components of the network. 3. In Microsoft Windows, the definition of elements such as fonts, templates, accelerators, and error messages are all stored in resource files.

RESOURCE INTERCHANGE FILE FORMAT

(RIFF) Platform-independent multimedia specification (published by Microsoft and others in 1990) that allows audio, image, animation, and other multimedia elements to be stored in a common format. See also Media Control Interface (MCI).

RESPONSE FILE

A file used to supply answers to an installation program's prompts. These answers are the responses users specify during a window-driven installation

RESTRICTED SERVICE LINE

An ISDN trunk capable of operating at 56Kbps. Restricted Service Line is common in the United States and Japan.

RESULT CODES

When you enter most modem commands, the modem displays a message on your screen, called a result code, that tells you the results of the command. In the factory setting, result codes are returned as English words that describe the conditions. You can also set the modem to display corresponding numbers instead of words.

RETRAINING

See CCITT V.32bis.

REVERSE ADDRESS RESOLUTION PROTOCOL

(RARP) The Internet Protocol used by a PC at startup to find its Internet address from its hardware address. The PC broadcasts a request that contains its physical hardware address and a server responds by sending the PC its Internet address.

RFC

See Request for Comment.

RFE

Removed from equipment. (used)

RFS

See Remote File System.

RG-58U

50ohm coaxial cable - used for Ethernet thinnet trunk cable, and other uses.

RG-62U

93ohm coax - Used exclusively on IBM cabling systems and all compatible systems.

RG-U

RG = military designation for coaxial cable U = general utility

RG59U

75ohm coax - Interconnect for Wang system and other compatible voice and data systems.

RGB

Red-Green-Blue. A type of computer display output signal comprised of separately controllable red, green and blue signals. The other technique for output display is composite video, which typically offers less resolution than RGB.

RH

Request/Response Header

RI

Routing Information

RIC

Remote Intelligent Communications

RIF

See Ring Interface. See Routing Information Field.

RIFF

See Resource Interchange File Format.

RII

Route Information Indicator

RING

Telephones: "-" side of the voice phone line pair, also called "b". Computers: See Processor Ring. See Ring Topology.

RING INTERFACE

(RIF) A component of the token-ring interface card that interconnects the serial data port of the TMS380C16 to the token-ring interface card connector.

RING TOPOLOGY

A network configuration where a series of attached devices are connected by unidirectional transmission links to form a closed path. Each node is a repeater, and nodes are physically connected into a physical ring circuit. This topology can be used for Token Ring and FDDI LANs, though star-wired ring is preferred. See Star-Wired Ring.

RINGBACK NUMBER

A phone number that will immediately ring the telephone from which it was called. In most instances you must call the ringback number, quickly hang up the phone for just a short moment and then let up on the switch, you will then go back off hook and hear a different tone. You may then hang up. You will be called back seconds later.

RIP

See Routing Interior Protocol. OR See Router Information Protocol.

RIPE

See Reseaux IP Europeenne.

RIPL

Remote Initial Program Load

RIPL SERVER

A server in Extended Services that provides RIPL support for one or more RIPL work stations and remote initial program loads those work stations.

RIPL WORKSTATION

Usually a medialess work station that is remote initial program loaded by an RIPL server.

RISC

See Reduced Instruction Set Computer.

RJ-45 CONNECTOR

Similar to a modular telephone plug, but larger. Used for Twisted-Pair Ethernet wiring.

RJE

Remote Job Entry

RKE

Remote Keyless Entry

RLE

See Run Length Encoding.

RLN

Remote LAN Node

RLOGIN

An application that provides a terminal interface between UNIX hosts using the TCP/IP network protocol. A service offered by Berkeley UNIX which allows users of one machine to log into other UNIX systems (for which they are authorized) and interact as if their terminals were connected directly. Unlike Telnet, Rlogin assumes the remote host is (or behaves like) a UNIX machine.

RLP

Resource Location Protocol

RM

IC part number prefix indicating Raytheon Semiconductor.

ROFL

Rolling on floor laughing.

ROSE

See Remote Operations Service Element.

ROT13

ROT13 is a very simple encryption mechanism for text. Imagine the 26 characters of the alphabet on a wheel. To ROT13 encrypt one character, simply rotate the wheel 13 positions from the original character position. To decrypt, turn the wheel another 13 positions. The purpose of ROT13 is not really encryption, but rather to shield the casual reader from potentially offensive material, or from what people call "spoilers". See Spoiler.

ROUTABLE PROTOCOL

A network protocol that can work with nonproprietary routers. Traditional routers use the network packet header fields to identify network addresses (network numbers) and node addresses for ultimate source and destination nodes (or hosts) for packets of data. This scheme for routing packets across internetworks is used with OSI, NetWare (IPX), TCP/IP, and AppleTalk network protocols. Conversely, other network protocols, such as IBM's SNA and NetBIOS protocols, use a name for the source and destination resource and do not identify each LAN or WAN as a separate entity. See Nonroutable Protocols, Internetworks, Routers, Network Address, Node, and Address.

ROUTER

A router uses a packet's IP destination address to determine which network or network segment is its destination. A router can find the best way to transmit data between networks. This may involve hops across multiple networks. Routers use special protocols that let them talk to each other and advise their peers of available routes, hop counts, time to destination, and router maintenance. Upper-layer protocols must be the same. A device that reads network layer packet headers and receives or forwards each packet accordingly. A router does not in any way process LAN frames, because the LAN frame is discarded once the LAN has delivered the frame to the NIC driver. The destination network address in the header is read and checked against the routing tables the router has learned; where necessary, the header hands off the packet to the NIC driver for the destination network address. NetWare operating systems, version 2.0 and later, incorporate an internal router that enables the NetWare server to function with multiple LANs (network addresses), regardless of whether the LANs are of the same type. Novell incorrectly described internal routers as 'internal bridges' in documentation up to versions 2.15 and 3.10. In version 2.2 and 3.11 documentation, they are described correctly. Routers are distinctly different devices from bridges, and integrators need to learn the difference so that they can properly configure NetWare operating systems (and routers) during installation. Many NetWare integrators and industry writers still incorrectly use the term 'bridge' to describe routers, causing needless confusion in understanding routable protocols, bridges, and internetworking. External routers (Novell and third-party) are stand-alone routers that perform the same functions as a server's internal router, except that the router itself is seldom the ultimate destination for packets. The protocol used for NetWare (and third-party) routers to communicate and function is Router Information Protocol (RIP). RIP packets are periodically broadcast by all routers to inform all other routers of their network addresses and number of hops (passes across routers to get to a network address). Routers connect LANs and WANs into internetworks, but must be able to process the network packets for specific types of network protocol (NetWare's network protocol is IPX). Many routers process various packet types and therefore are termed multiprotocol routers. See IPX, Bridge, OSI Model, and UNA.

ROUTER INFORMATION PROTOCOL

(RIP) See Routing Interior Protocol.

ROUTINE

A program, or a sequence of instructions called by a program, that has some general or frequent use.

ROUTING INFORMATION FIELD

(RIF) Contains information relative to the network layer for devices routing in a DNA environment.

ROUTING INFORMATION PROTOCO

(RIP) See Routing Interior Protocol.

ROUTING INTERIOR PROTOCOL

(RIP) A distance-vector IGP used between routers to exchange routing information. A protocol and packet format that exchanges routing information among routers. RIP packets contain multiple information fields that include the network addresses, number of hops (traverses across routers), and number of ticks (estimate of time delay) for available LANs and WANs. RIP packet format is a subset of XNS.

ROUTING SUBDOMAIN

A set of ISs and ESs located within the same routing domain.

ROUTING-BRIDGE

See Brouter.

RPC

See Remote Procedure Call.

RPS

Ring Parameter Service

RS-170

The EIA (Electronics Industries Association) standard for the combination of signals required to form NTSC monochrome (black and white) video. The broadcast standard; specifies maximum amplitude of 1.4V, peak-peak including synchronization pulses. Also, sets standard 30 frames per second.

RS-170A

The EIA standard for the combination of signals required to form NTSC color video. It has the same base as RS170, with the addition of color information.

RS-232

See CCITT V.24.

RS-232 WEDGE

This places the wedge between an asynchronous or serial terminal and the host computer.

RS-232C

A standardized connection system for connecting a device to the serial port of a computer or terminal. This is the recommended standard of the Electronic Industries Association (EIA) for exchanging information between Data Terminal Equipment (such as computers) and Data Communications Equipment (such as modems).

RS-244-B

An EIA standard for character and tape punch codes used for numerical control. These codes are different than ASCII codes.

RS-274-D

An EIA standard for programming formats used for contouring and positioning with numerically controlled machines. A common format for U.S. machine tools.

RS-358-B

An EIA standard for character and tape punch codes used for numerical control. These codes are the same as ASCII codes and are more compatible with general computer systems than the RS-244-B codes.

RS-422

An EIA standard that specifies electrical characteristics of balanced-voltage digital interface circuits in a point-to-point link. A balanced-voltage system with a high level of noise immunity.

RS-423

An EIA standard that specifies electrical characteristics of unbalanced voltage digital interface circuits in a point-to-point link. Similar to RS-422, but unbalanced.

RS-449

An EIA standard that specifies mechanical and functional characteristics for digital interface circuits. General purpose 37-pin and 9-pin interface for DCE and DCE, employing serial binary data interchange. This standard is used in combination with either RS-422 or RS-423.

RS-485

An EIA standard that specifies electrical characteristics of balanced-voltage digital interface circuits in a multi-point link. Balanced interface similar to RS422, but using tri-state drivers for multidrop applications. Up to 64 devices may be interconnected with RS-485.

RS-530

Supersedes RS-449 and copliments RS-232. Based on a 25-pin connection, it works in conjunction with either electrical interface RS-422 (balanced electrical circuits) or RS-423 (unbalanced electrical circuits). RS-5309 defines the mechanical/electrical interfaces between DTEs and DCEs that transmit serial binary data, whether synchronous or asynchronous. RS-530 provides a means for taking advantage of higher data rates with the same mechanical connector used for RS-232. However, RS-232 and RS-530 are not compatible!

RSB

Repair Service Bureau

RSN

Real Soon Now - Used with heavy sarcasm. Actually a long time from now.

RSX

Realtime resource-Sharing eXecutive

RT

Routing Type

RTEL

Lantronics "reverse telnet" software allows hosts using TCP/IP to establish a session with a device attached to a terminal server port.

RTELNET

Remote Telnet Service

RTFM

Read the *#@%#$ manual

RTS

Request to Send signal in RS-232-C. An RS-232C signal that requests the modem to send data. It initiates any data transmission between the computer (or terminal) and the modem. It is answered by a Clear to send (CTS) signal. A request from one device to a modem to prepare to transmit. With full-duplex control, RTS is always asserted. With half-duplex control, it is turned on when the device has permission to transmit: otherwise it is off.

RTS

See Request to Send.

RTSE

See Reliable Transfer Service Element.

RTV

Real Time Video. Single step compression of video.

RU

Request/Response Unit

RUGGED

Too heavy to lift.

RUIP

Removal and Insertion Under Power or Remote User Information Program

RUN LENGTH ENCODING

(RLE) A data compression technique in which an image is fast-scanned and only the lengths of runs of consecutive pixels with the same property are stored. Microsoft's video compression algorithm for base level multimedia PCs. Compresses 8-bit sequences only. Playback is also in 8 bit and isn't scalable for higher power PCs.

RUP

Show host status of local machines (UNIX command)

RUSERSQ

Show sho is logged in on local machines (UNIX command)

RVD

Remote Virtual Disk Protocol

RWALL

Send a message to all users over a network (UNIX command)

RWHO

Who's logged in on local machines (UNIX command)

RXD

Received Data signal in RS-232-C. Serialized data input to the device.

RZR

Razor (1911)