R

RA              Random Access.
RA              Relocation-Address register. The starting address of a
                program in the computer's physical-address space. Hence, the
                value added to a logical address by the memory-relocation
                hardware to get the corresponding physical address of the
                reference, in the CDC 6600 memory protection.
RAD             Rapid Application Development.
RAID            Redundant Array of Inexpensive Disks.
RAM             Random Access Memory. A memory that provides access to all of
                its data cells in essentially the same amount of time. See
                also DRAM, SRAM.
RARP            Reverse Address Resolution Protocol. The RARP is essentially
                a "who I am" broadcast that is transmitted by a new station
                entering the network. The broadcast is responded to by an
                RARP server that maps the requester's Ethernet address to an
                IP address appropriate to the internetwork configuration.
RAS             Random Access Storage.
RAS             Reader Admission System.
RAS             Reliability, Availability, Serviceability.
RAS             Remote Access Service.
RAT             Register Alias Table.
RBBS-PC         Remote Bulletin Board System for the PC.
RBOC            Regional Bell Operating Companies.
RBSE            Repository-Based Software Engineering.
RBT             Remote Batch Terminal. A terminal used for entering jobs and
                data into a computer from a remote site for later batch
                processing.
RC              Record Code.
RCU             Rack Controller Unit.
RDA             Remote Database Access.
RDBMS           Relational DataBase Management System.
RDL             Remote Digital Loopback. This test, like the LDL test,
                verifies the condition of both modems and the phone link.
RDRAM           Rambus Dynamic Random Access Memory.
RDS             Relational Data System. The term in IBM manuals called RDS 
                came from the original System R implementation. It encompasses
                the precompiler, the bind, and the run-time supervisor.
REN             Remote Enable. Allows instruments to switch to remote control.
REPROM          REProgrammable Read Only Memory.
RF              Radio Frequency.
RFC             Request For Comment.
RFMS            Remote File Management System. See also TDMS.
RFS             Radio Frequency Signaling.
RGB             Red-Green-Blue. The color specification mechanism normally
                used in computer displays, where colors are separated into
                their primary-color components.  See also YUV.
RI              Ring Indicator. An input to the 8250 UART, generally from a
                modem, that becomes active when the telephone is ringing.
RIFF            Resource Interchange File Format. Microsoft has created a
                basic file structure for most of the file types used with
                Windows. This makes it easier to use different formats
                simultaneously.
RIOS		Risc Input/Output System.
RIP             Routing Information Protocol. This protocol is used by XNS
                routers to maintain routing tables in an internetwork.
RISC            Reduced-Instruction-Set Computer. A computer with a
                relatively simple load-and-store instruction set and only
                register-to-register operate instructions. Typical RISC
                machines have large register sets, multiple functional units
                and pipelined instruction and execution units.
RJT             Remote Job Entry. Input of a batch job from a remote site and
                receipt of output via a line printer or other device at a
                remote site.
RLA             Run Length/Amplitude.
RLE             Run-Length Encoding.
RLL             Run-Length Limited. A method of encoding data as a series of
                magnetic flux reversals on disk or tape.  RLL can achieve
                higher data densities than MFM recording because it encodes
                the data such that (on average), fewer than one flux reversal
                per data bit is required (however, timing becomes more
                critical).  RLL is actually an entire family of encoding
                methods, specified with two numbers indicating the minimum
                and maximum distances between one bits (flux transitions).
                The variant normally called RLL is RLL-2,7; RLL-1,7 and
                RLL-3,9 are also in use. MFM is in effect RLL-1,3.  See also
                FM, MFM.
RLSD            Received Line Signal Detect. The input signal to the 8250
                UART that indicates the presence of a carrier frequency on
                the transmission line.
RMA             Return Materials Authorization.
RMOS            Refractory Metal-Oxide Semiconductor.
RNG		Random Number Generator.
RO              Relocation Offset. The starting address of a program in the
                computer's physical-address space. Hence, the value added to
                a logical address by the memory-relocation hardware to get
                the corresponding physical address of the reference, in the
                CDC 6600 memory protection.
ROB             ReOrder Buffer.
ROM             Read Only Memory. A memory that can only be read.
ROM BIOS        Read Only Memory Basic Input/Output System. The basic I/O
                system of an IBM PC, which comes in a ROM chip on the mother
                board and provides direct control for the hardware devices.
ROSE            Relational Object System for Engineering. The ROSE system was
                developed at Rensselaer Polytechnic by Hardwick and Spooner.
                It is a structurally OODBMS supporting aggregation,
                generalization, and association.
ROSE            Remote Operations Service Element. A protocol entity forming 
                part of the application layer. It provides a general facility 
                for initiating and controlling operations remotely.
RP 3            Research Parallel processor. It is a testbed for the hardware 
                and software of highly parallel MIMD supercomputers design.
RPC             Remote Procedure Call.
RPROM           ReProgrammable Read Only Memory.
RR              Round Robin. It is the preemptive analogue of FCFS in which 
                the operating system, in addition to permitting a process to 
                yield the CPU, actually forces it to do so if the process has 
                executed continuously for a long time.
RRF             Retirement Register File.
RS              Record Separator.
RS-232C         The RS-232C is a standard published in 1969 by the EIA. The
                RS is an acronym for Recommended Standard and the 232 is the
                identification number for that particular standard.
RSA             Rivest-Shamir-Adleman.
RSP             Reliable Stream Protocol.
RSRB            Remote Source Route Bridging.
RT              Reperforator/Transmitter.
RTC             Real-Time Clock.
RTF             Rich Text Format.
RTIC            Real-Time Interface Co-processor.
RTS             Remote Takeover Systems. RTS, as its name implies, allows
                callers to dial in and take over the operation of a remote PC.
RTS             Request permission To Send. One of the handshake signals
                generated by a universal asynchronous receiver-transmitter
                (UART) to inform the attached device that the UART has data
                it is ready to transmit.
RTS/CTS         Request To Send / Clear To Send. See RTS, CTS.
RX		Runtime-eXtension.
RXOR		Rotated eXclusive OR.
RZ              Return to Zero.
