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Computer, Telephony & Electronics
Industry Glossary


A computer industry acronym for Return Authorization. You must have an RA in order to return equipment for service, validation, upgrades, or exchange. Most companies track such returns by this number. See RMA.


1. Acronym in the telephony fields for a Record/Announce Device such as a Digital Announcer.
2. See RAN.
3. The common abbreviation for radian.


A unit of plane angle measure equal to the angle subtended at the center of a circle by an arc equal in length to the radius of the circle. One radian is defined as equal to 360°/2PI, or reduced further to 180°/PI, which is approximately 57° 17' 44.6". 1° (degree) equals PI/180 radians. See RAD.


1. An acronym for Remote Access Dial In User Service; also for Remote Authentication Dial-In User Service and Remote Authorization Dial-In User Service.
2. The only of the three options that has a defined standard protocol is Remote Authentication Dial-In User Service. It is most frequently used by various ISPs for user authentication and accounting.
3. Remote Access Dial-In User Service is a process often used to control sessions through a terminal server. See RAS.
4. Remote Authorization Dial-In User Service is a loosely defined protocol that is much more secure than just authentication.


1. Acronym for Reverse ADSL. A term for a DSL stream that is asymmetrical in the upstream direction; that is, a reverse ADSL link has a small downstream and large upstream communications path.
2. Acronym for Rate Adaptive Digital Subscriber Line.


1. Short for Redundant Array of Independent (or Inexpensive) Disks, a category of disk drives that employ two or more drives in combination for fault tolerance and performance. RAID disk drives are used frequently on servers but aren't generally necessary for personal computers. There are number of different RAID levels. The three most common are 0, 3, and 5:
Level 0: Provides data stripping (spreading out blocks of each file across multiple disks) but no redundancy. This improves performance but does not deliver fault tolerance.
Level 1: Provides disk mirroring.
Level 3: Same as Level 0, but also reserves one dedicated disk for error correction data. It provides good performance and some level of fault tolerance.
Level 5: Provides data stripping at the byte level and also stripe error correction information. This results in excellent performance and good fault tolerance.
2. Reasonably good bug killer.


1. The bracket that holds drives into a chassis.
2. Either pole or conductor of a power supply; one is positive and one is negative.

random access

Refers to the ability to access data at random. The opposite of random access is sequential access. To go from point A to point Z in a sequential access system, you must pass through all intervening points. In a random access system, you can jump directly to point Z. Disks are random access media, whereas tapes are sequential access media. The terms random access and sequential access are often used to describe data files. A random access data file enables you to read or write information anywhere in the file. In a sequential access file, you can only read and write information sequentially, starting from the beginning of the file. Both types of files have advantages and disadvantages. If you are always accessing information in the same order, a sequential access file is faster. If you tend to access information randomly, random access is better. Random access is sometimes called direct access, the reason Microsoft named the database product they make what they did.


1. Random Access Memory. This is the computer's main memory where program data is stored for quick retrieval. RAM is often confused with hard drive space, especially with the active use of virtual memory in Windows 95 and up. Most minimum computers now are equipped with 8 or 16 MB RAM, healthy RAM sizes are 32, 64, 128 MB and up. RAM is temporary storage. When the computer is turned off or restarted, anything in RAM is lost. RAM is actually a physical chip or module inside the computer; it is considered hardware.
2 The working memory of the computer into which application programs can be loaded and executed. It helps to have more of this "working space" installed when running advanced operating systems and applications. A configuration of memory cells that hold data for processing by a computer's central processing unit, or CPU; (see also memory). The term random derives from the fact that the CPU can retrieve data from any individual location, or address, within RAM.


Rambus, Inc. was founded in 1990 by Dr. Mike Farmwald and Dr. Mark Horowitz, both regarded as experts in electrical and computer engineering. The company is located in Mountain View, CA. Find them at HTTP://WWW.RAMBUS.COM. See also RDRAM and RIMM. Although the memory ideas from them had merit and were innovative, their memory was very costly, compared to others of similar performance but different design, and have since gone by the wayside. January 2001.


1. Acronym in the telephony fields for a Record/ANnounce device such as a Digital Announcer. Also used in conjunction with trunk or circuit.
2. See RAD.

random access memory - RAM

See RAM.


1. A memory function; an acronym for Row Address Select. A control pin on a DRAM used to latch and activate a row address. The row selected on a DRAM is determined by the data present at the address pins when RAS becomes active.
2. In computer memory technology, RAS, Row Address Strobe, is a signal sent to a dynamic random access memory (DRAM) that tells it that an associated address is a row address. A data bit in DRAM is stored in a cell located by the intersection of a row address and a column address. A CAS (column address strobe or select) signal is used to validate the column address. The signals are generally sent CAS before RAS.
3. An acronym for Remote Access Services, also known as Remote Authentication Services depending on the third party software vendor. RAS is a feature built into Windows NT that enables users to log into an NT-based LAN using a modem, X.25 connection or WAN link. RAS works with several major network protocols, including TCP/IP, IPX, and Netbeui. To use RAS from a remote node, you need a RAS client program, which is built into most versions of Windows, or any PPP client software. For example, most remote control programs work with RAS.
4. In telephony, an acronym for Remote Announcing System. This is a switch feature that allows an outside caller, with proper access, to make announcements over the local public or office announcing system.


A slang acronym, often used in telephony. Regional Bell Operating Companies.


RDC is an acronym for Remote Desktop Connection, a method of supporting a computer from another computer located remotely. RDC began with Windows XP. If you need XP assistance with the RDC operation, see XP Remote Desktop Support (RDC) to have one of our engineers help you.


Rambus DRAM technology is a system-wide, chip-to-chip interface design that allows data to pass through a simplified bus. Rambus uses a unique RSL (Rambus Signaling Logic) technology. Rambus is available in two flavors, RDRAM and Concurrent RDRAM. RDRAM has been in production since mid-1997 with Concurrent RDRAM production beginning in late 1997. The third line extension, Direct RDRAM, is in the initial stages of production that started in late 1999. In late 1996, Rambus, Inc. (the company) agreed to a development and license contract with Intel that led to Intel's PC chip sets supporting Rambus memory starting in 1999. Rambus DRAM is an evolutionary type of DRAM that uses a 16-18 bit data path and is designed to operate with FSB speed of 800MHz producing a burst transfer rate of 1.6 gigahertz. It is a dynamic RAM chip that under normal (as opposed to optimum) conditions, transfers data at 500MBytes/sec (3-10 times faster than DRAM and VRAM chips). Often associated with the term RIMM. See Rambus and get more information at HTTP://WWW.RAMBUS.COM.


Reactance is a form of opposition that electronic components exhibit to the passage of alternating current (AC) because of capacitance or inductance. When alternating current passes through a component that contains reactance, energy is alternately stored in, and released from, a magnetic field or an electric field. In the case of a magnetic field, the reactance is inductive. In the case of an electric field, the reactance is capacitive. Resistance and reactance combine to form impedance.


1. A text file included with an application that contains important (and often last minute) information about installing and using the application.
2. A text file on an FTP site that provides valuable information about the context of site.
3. Any text file that you are supposed to read before proceeding.

read receipts

An optional E-Mail feature that notifies you when a recipient has opened the E-Mail message you sent him. See also delivery receipts.


The de facto standard for streaming audio data over the World Wide Web. RealAudio was developed by RealNetworks and supports FM-stereo-quality sound. To hear a Web page that includes a RealAudio sound file, you need a RealAudio player or plug-in, a program that is freely available from a number of places. It was included in current versions of both Netscape Navigator (through 7) and Microsoft Internet Explorer (through 4.01); it is no longer included as Microsoft has a competing product. See RealVideo.

really nice person

1. Usually abbreviated RNP in chat rooms and E-Mail or messaging.
2. Our staff.

real time

Events that happen in real time are happening virtually at that particular moment. When you chat in a chat room, or send an instant message, you are interacting in real time since it is immediate. Real time business is interactive and "posting" occurs during the transaction. Most accounting systems are NOT real time. Most accounting systems are done in a batch mode to facilitate posting. The exact opposite of real time is batch transactions or "after the fact" actions in accounting systems. An example of real time communication would be the telephone by contrast to a FAX, E-Mail or even worse, mail. Direct interactivity is mandatory in real time processing.


A streaming technology developed by RealNetworks for transmitting live video over the Internet. Though designed originally in 1995, the process is just coming of age and is being used experimentally on the Internet. RealVideo uses a variety of data compression techniques and works with both normal IP connections as well as IP Multicast connections. The process is currently "jerky" and somewhat slow because it requires a lot of bandwidth and often that is not readily available. It works well with DSL and faster connections. Also see RealAudio.

Real Soon Now - RSN

In shorthand form or as a normal phrase, a term used to indicated "quickly". Whenever one's previous time commitments allow. A phrase used to indicate that a feature or program will be available sometime between the near-future and the distant-future. It is thought that this phrase was originally coined by Microsoft's tech staff to answer the question of "When will the bugs be fixed?"


A software procedure that calls itself one or more times. Programmers often refer to this as a re-entrant operation; it must be in the strictest sense of the definition. Correctly written, a recursive function does NOT use more memory on each additional operation for the function itself; just the initial memory is used for code and the minimum amount used to keep track of each call operation. Please see re-entrant. Also see thread-safe.


Normally considered a diode, however the diode is usually thought of as a signal device, with currents of 1 AMP or less; and a rectifier, a power device with currents up to 1,000 amps or more. Also, the term rectifier is usually associated with rectification of some sort whereas a diode can be a rectifier, a Zener, a four-layer device or a signal block.


The process of changing AC current to DC current.

Reed Solomon

A techie term for a forward error correcting code that is used to offset the effects of bit error bursts in the receive bit stream.


A re-entrant function is one that can be called by more than one program at the same time. A good example is the general description of an operating system, more specifically, the Windows kernel function. By definition, a re-entrant function CAN be recursive, but does not HAVE to be. Please see recursive.

Reference Desk

A channel of many
ISP online services that offers access to dozens of databases and reference books such as encyclopedias and dictionaries. This glossary could be considered as a Reference Desk.


1. To clear the screen or a part or section of the screen and redraw it where it was previously.
2. A cycle in a memory hardware function. An electrical process used to maintain data stored in DRAM. The process of refreshing electrical cells on a DRAM component is similar to that of recharging batteries. Different DRAM components call for different refresh methods. The process is used to restore the charge in DRAM memory cells at specified intervals. The required refresh interval is a function of the memory cell design and the semiconductor technology used to manufacture the memory device. There are several refresh schemes that may be used. Normal industry usage is 1K, 2K or 4K refresh on 16 Mb DRAMs. How fast it happens is called a refresh rate. Dynamic RAM needs to be refreshed thousands of times per second or it will lose the data stored in it.
3. Though frequently just called refresh, a special refresh action known as auto refresh, is commonly referred to as CAS-before-RAS or refresh CE before RE refresh. An internal address counter increments the row address each time the memory controller initiates a CAS before RAS refresh cycle.
4. Though most frequently called reload, web browsers use the same theory to show or update information shown in the browser.
5. To recharge a device with power or information.
6. A Pepsi and a moon pie after a couple of hours of programming.

refresh rate

1. A specification determined by the number of rows on a DRAM component that must be refreshed. The two most common refresh rates are 2K and 4K, though there are faster and slower.
2. Video display monitors must be refreshed often, many times per second. The refresh rate for a monitor is measured in hertz (hz) and is also called the vertical frequency, video cycles, vertical scan rate, frame rate or vertical refresh rate. The old standard for monitor refresh rates was 60hz, but a new standard developed by VESA sets the refresh rate at 75hz for monitors displaying resolutions of 640x480 or greater. This means that the monitor redraws or renews the display 75 times per second. The faster the refresh rate, the less the monitor flashes or flickers. The more expensive the monitor, generally, the faster the refresh rate. Some people see refresh rates differently than others. For some people, even 75hz is not fast enough to keep them from seeing the flashes that cause headaches, eye problems and other mild inconveniences.


1. Several memory locations (depending of the processor itself) that are used by the internal functions of the computer or by assembly language programmers. Data can be PUSHed or POPed to or from a particular register to accomplish a particular task. End users are not normally concerned with registers or the content of them. For more information about registers, we suggest that you take a starting course in assembly language for the particular processor in question. This is roughly the equivalent of "setting a variable" in higher level programming languages.
2. The process of placing on record with a hardware or software company a record of purchase of a device or system, allowing them to notify you of modifications, changes or upgrades.


First initiated in Windows 95, it is the central location for program information in subsequent Windows operating systems and applications. This replaced Windows .INI files for each application and for Windows itself.


Installing a program onto a computer for a second (or greater) time in order to overwrite the old software and hopefully fix a problem. If file corruption is suspected, you have deleted some files inadvertently or for other reasons, this can and often does fix "strange" problems.


These are very useful but expensive electrical switches that can control very large amounts of electrical energy. A relay consists of a switch that is operated by an electrical magnet. There are several types, including normally-open (NO) and normally-closed (NC). In an NO relay, when the magnet is engaged, the metal parts of the switch are pulled together. When the magnet is off the metal parts of the switch are pushed apart. The action is the opposite way around for an NC relay. This is an example of a switch containing moving parts, compared to newer technology solid state devices.


A term used in conjunction with search engine results. Based on results, the more appropriate the returns that are accurate and within the parameters of the target search words or phrase, the more relevant the search. Often results are returned that do include something containing all or part of your target key, however, the information is not relevant to the desired result.

remote login

Operating a remote computer over a network as if it were a local computer. This can be accomplished via one of several protocols, including telnet and the UNIX program rlogin.

remote support

The ability of a technician to connect remotely to another computer for the purposes of resolving problems. Once connected, the technician can operate that remote computer as if he was local to it. The technician and remote user are in touch via a conversation area, or chat area; the user may observe what the technician is doing at all times. The user can grant limited or unlimited permission for use but MUST always grant some level of permission for the technician to gain entry to that computer. Remote support works best on broadband Internet connections. Also please see RDC.


A telephony industry term and acronym; Ringer Equivalency Number. By definition, 1 REN = the energy to ring one Plain Old Telephone POL or Single Line Telephone (SLT). The REN number can be found on the FCC label on the device. The total ringer load on a line is equal to the sum of all the REN numbers of all the telephone devices connected to the line.


To perform the calculations necessary to draw a complex three-dimensional image.


A uni-functional network device that performs only one task. It gets a signal (receives) from the network and sends it back out on the network (re-transmits) in a much higher amplitude to allow greater distances to be spanned. Most repeaters do not evaluate the protocol or packets; they only amplify the signal bit by bit. This is most often used with backbones on ARCNet and with Ethernet.


1. The measurement of how much a resistor impedes the flow of electrons in an electrical or electronic circuit. Resistance is measured in ohms. See our Parallel Resistance Calculator and our Series Resistance Calculator to resolve values for such calculations.
2. "Mac"ies


1. An electrical or electronic component that resists the flow of electrons in a circuit. There are several types of resistors including carbon, ceramic, fixed wirewound, variable wirewound, stationary adjustable wirewound and forms of integrated circuits. How much a resistor impedes the current flow is called resistance and is measured in ohms. Most resistors have a fixed value as to how much resistance they will display. Wattage, qualities and tolerance values vary according to needs. There is an industry standard in color codes for that and you can see it by clicking your mouse here. Want to know about Ohm's Law? If so, please click here or click here!
2. A programmer that is hesitant to work.


This is a measure of how sharp an image will appear on a monitor. Usually it's expressed as a number of dots (pixels) across by a number of dots high. Some common resolutions are 640 x 480, 800 x 600 and 1024 x 768. The higher the resolution, the sharper the image, because there are more dots. Also, the smaller the screen, the sharper the resolution, because the dots are smaller. One pixel is the smallest area that can be manipulated by the computer. Resolution is always stated as the horizontal number of pixels by the vertical number of pixels. A screen displaying1600 x 1200 pixels has 1200 rows, each 1600 pixels wide. They are often displayed with an additional number which is the number of colors in the display that are possible.


The name given to any disk drive, printer, peripheral device, directory, program, file or data that can be shared among users on a network.

response time

A measurement of the time between a request for information over a network and the network's fulfillment of that request. "Overall response time" is an aggregate or average measurement of various response times over a particular network or through a particular host.

reverse polarity

A condition where an electrical device needing DC electricity is intentionally or by accident, reversing the inbound power. In most conditions, ground is the negative (-) side of the power source. The positive power voltage source is NOT ground. In a reversed polarity situation, power is positive (+) and is also ground. As an example of this in the automotive industry, in the 1970s, some White (a brand) trucks were positive ground instead of negative ground. (Why? you ask... I don't know... Some engineer had to think there was a good reason for going against industry standards.) Any add on electrical devices such as CB radios and radar detectors, both popular trends of the time, had to be capable of reverse polarity. In reality, that means that chassis ground and electrical ground reference points cannot be the same. In most electrical circuits, they are.
The opposite of that is where polarity is accidentally reversed. As an example of the same time, while putting a CB radio into your car, you connect the radio's positive lead to ground and the ground lead to the car's 12 volt power source (13.8 volts if the engine is running). When the radio is turned on, electrons flow the wrong way into the radio. In most cases, engineers planned for that possibility and designed the power entry circuits so that a polarity diode would short out if that happened to protect the rest of the electronics in the radio. When the polarity diode sensed voltage on the cathode instead of the anode, it allowed the flow to pass, tripping a breaker, or more likely, blowing an inline fuse.
To help cut down on such situations in the most likely of conditions, engineers today have tried to keep the possibility from happening. In most automotive add on devices, the power supply cord now comes with a cigarette lighter plug on it so that the installer, who may not be a qualified electronics person, cannot accidently reverse the power. Still, the most frequent cause of problems to cell phones is reversed polarity due to charging cables being hooked up backwards in a car. See polarity.


An abbreviation of the term Radio Frequency. It refers to alternating current (AC) having characteristics such that, if the current is input to an antenna, an electromagnetic (EM) field is generated suitable for wireless broadcasting and/or communications. These frequencies cover a significant portion of the electromagnetic radiation spectrum, extending from nine kilohertz (khz), the lowest allocated wireless communications frequency band (it's within the range of human hearing), to several thousands of gigahertz (ghz). When an RF current is supplied to an antenna, it gives rise to an electromagnetic field that propagates through space. This field is sometimes called an RF field; in less technical jargon it is a "radio wave." Any RF field has a wavelength that is inversely proportional to the frequency. In the atmosphere or in outer space, if f is the frequency in megahertz and s is the wavelength in meters, then s = 300/f. The frequency of an RF signal is inversely proportional to the wavelength of the EM field to which it corresponds. At 9 khz, the free space wavelength is approximately 33 kilometers (km) or 21 miles. At the highest radio frequencies, the EM wavelengths measure approximately one millimeter (mm). As the frequency is increased beyond that of the RF spectrum, EM energy takes the form of infrared (IR), visible, ultraviolet (UV), X rays, and gamma rays. Many types of wireless devices make use of RF fields. Cordless and cellular telephone telephones, radio and television broadcast stations, satellite communications systems, and two-way radio services all operate in the RF spectrum. Some wireless devices operate at IR or visible light frequencies, whose electromagnetic wavelengths are shorter than those of RF fields. Examples include most television set remote control boxes, some cordless computer keyboards and mice, and a few wireless hi-fi stereo headsets. The RF spectrum is divided into several ranges, or bands. With the exception of the lowest frequency segment, each band represents an increase of frequency corresponding to an order of magnitude (power of 10). The table depicts the eight bands in the RF spectrum, showing frequency and bandwidth ranges. The SHF and EHF bands are often referred to as the microwave spectrum.


Abbreviation for Request for Comment. One of a long-established series of informal informational documents and standards that guide the development of the Internet. The most famous is RFC 822, the Internet mail standard drafted by Dave Crocker.


An abbreviation for Radio Frequency IDentification. It is a technology that incorporates the use of electromagnetic or electrostatic coupling in the radio frequency (RF) portion of the electromagnetic spectrum to uniquely identify an object, animal, or person. RFID is coming into increasing use in industry as an alternative to the bar code. The advantage of RFID is that it does not require direct contact or line-of-sight scanning. An RFID system consists of three components which are an antenna, a transceiver (often combined into one reader), and a transponder (the tag, bracelet or ID object). The antenna uses radio frequency waves to transmit a signal that activates the transponder. When activated, the tag transmits data back to the antenna. The data is used to notify a programmable logic controller (PLC) that an action should occur. The action could be as simple as raising an access gate or as complicated as interfacing with a database to carry out a monetary transaction. Low frequency RFID systems (30 KHz to 500 KHz) have short transmission ranges (generally less than six feet). High frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer longer transmission ranges (more than 90 feet). In general, the higher the frequency, the more expensive the system. RFID is sometimes called dedicated short range communication (DSRC).


A designation of coaxial cable used for 52 ohm data transmission. In computer networks, it is used for Ethernet topology called "thick-net".


A designation of coaxial cable used for 52 ohm long run RF broadcasting in business, HAM and CB radio, and in certain limited applications, data transmission. In computer networks, it is not used because of unique capacitance characteristics and gives way to "thick-net" RG-6.


A designation of coaxial cable used for 52 ohm, short run RF broadcasting (radio) or for data transmission. It is the "little brother" of RG-6. In computer networks, it is used for Ethernet topology called "thin-net". Most often, the RG-58A/U designation type cable is used. This can be used in a total network topology but us normally used as a backbone.


A designation of coaxial cable used for 75 ohm, long run RF broadcasting (radio) or for television transmission and reception. In radio transmission, it is usually used in parallel antenna installations called co-phasing. In computer networks, it is only used for special application devices on ARCNet topology.


A designation of coaxial cable used for 68 ohm, long run RF data broadcasting (radio) or for computer network transmission and reception in ARCNet installations.

Rich Text Format

A format for text documents that includes formatting attributes, such as different fonts and typefaces.


An acronym for Rambus Inline Memory Module. RIMMs, from Rambus, Inc., Mountain View, CA, (See them at HTTP://WWW.RAMBUS.COM.) use a very different approach than Cached DRAM and Enhanced DRAM to increase speed. By concentrating on improvements to the memory bus, RDRAM is able to combine IC level improvements with a bus architecture that is optimized for the new DRAM design. Each Rambus chip has an onboard controller circuit that handles address decoding and page cache management. By combining these chips with the new Rambus Channel, byte-wide multiplexed bus, a memory system with a low access time and an extremely fast data transfer rate is created. It is important to note that this is a system level improvement, not just a component upgrade. The Direct Rambus™ high-speed memory interface enables the highest DRAM performance, 1.6Gb/sec/DRAM device. The technology spans multiple DRAM generations - from 32Mb to 1Gb densities. The Direct Rambus RIMM Module is a next-generation high-performance plug-in memory module for PC main memory. Developed in conjunction with Intel Corporation, Direct Rambus technology has the performance/cost ratio demanded by the high clock-rate microprocessors used in mainstream PCs started shipping in 1999. The RIMM module conforms to the standard DIMM form factor, but it is not pin-compatible. Its architecture is based on the electrical requirements of the Direct Rambus Channel, a high-speed bus operating at a clock rate of 400MHz which enables a data rate of 800MHz (data is clocked on both clock edges). A two byte-wide data channel is used resulting in a peak data transfer rate of 1.6 Gbytes per second. The bus uses transmission line characteristics to maintain high signal integrity. See RDRAM.

ring back

A telephony term; the sound you hear when the phone you call is ringing. This is often called a ring signal.

ringdown circuit

A telephony circuit connecting 2 devices so that when one device goes off hook it automatically rings the other device.

ring generator

A telephony term; a circuit producing AC voltage that is higher that 50 VRMS and has a frequency of 20 Hz.

ring network

Ring networks are highly expensive networks usually constructed for high performance and a large number of devices connected over one LAN. Each computer in a ring network is connected to the next computer in a circular formation. The opposite of a ring network is a star network. There are also certain types of BUS networks.


A cell phone term; the sound made when the phone rings. Many can be stored in the phone, generally in .MP3 files format, so as to have a different tone for different callers. Ringtones can be downloaded from the Internet at different sites. Check out our list cell ringtone vendors or free locations.

ring trip

A telephony term; the process of stopping the AC ring signal and connecting the voice path at the CO when the ringing telephone is answered.

ring voltage

A telephony term; a 20 Hz AC voltage higher than 50V superimposed on the phone line to ring bells, activate ring detectors in phone systems, FAXs, modems, and other telecom devices.


Pronounced risk, acronym for reduced instruction set computer, a type of microprocessor that recognizes a relatively limited number of instructions. Until the mid-1980s, the tendency among computer manufacturers was to build increasingly complex CPUs that had ever-larger sets of instructions. At that time, however, a number of computer manufacturers decided to reverse this trend by building CPUs capable of executing only a very limited set of instructions. One advantage of reduced instruction set computers is that they can execute their instructions very fast because the instructions are so simple. Another, perhaps more important advantage, is that RISC chips require fewer transistors, which makes them cheaper to design and produce. Since the emergence of RISC computers, conventional computers have been referred to as CISCs (complex instruction set computers). There is still considerable controversy among experts about the ultimate value of RISC architectures. Its proponents argue that RISC machines are both cheaper and faster, and are therefore the machines of the future. Skeptics note that by making the hardware simpler, RISC architectures put a greater burden on the software. They argue that this is not worth the trouble because conventional microprocessors are becoming increasingly fast and cheap anyway. To some extent, the argument is becoming moot because CISC and RISC implementations are becoming more and more alike. Many of today's RISC chips support as many instructions as yesterday's CISC chips. And today's CISC chips use many techniques formerly associated with RISC chips.


A standard connector used for telephone connections on telephone cables that go between the wall and the phone or telephone device, such as a modem, answering machine, FAX, switch or amplifier. It has the ability to handle 4 wires which usually equates to 2 phone lines.


A standard connector used for network connections on computer network cables or multi-line telephone cables that go between the wall and the phone or telephone device, such as a modem, answering machine, FAX, switch or amplifier. It has the ability to handle 8 wires which usually equates to 2 network lines or 4 phone lines. On network connections, it can handle 2 computers but is normally only used for 1 at a time.


An acronym for Run Length Limited, an encoding scheme used to store data on certain PC hard disks. RLL produces faster data access times and increases a disk's storage capacity over the older encoding scheme called MFM (modified frequency modulation), by about 30% and 50% respectively. Technically, any disk drive can use MFM, RLL, or some other advanced encoding scheme. The one used depends on the integrated disk controller technology within the disk drive. This scheme was popularized in the late 1980s when Seagate introduced a "new" drive and controller combination. In reality, the drive was the same, the old die hard foundation of the time, ST225 21MB workhorse; however, the capability changed due to the controller capability. In its era, the ST225 was shipped in about 98% of all new computers. The difference was a new controller that gave the drive a 1 to 1 interleave factor and the ability to have 26 sectors per track compared to the older MFM encoding of 17 sectors and an interleave of 3 or 4. The "new" drive was designated the ST238. In that time period, the designation was for ST, Seagate Technology, and the number was for the form of the drive (5.25 or 3.5 inches, full or half height) and the UNformatted capacity of the drive. The ST225 was a half height, 5.25" MFM drive of 25MB unformatted. Depending on the drive, the designation also told the interface type (SCSI, MFM, RLL, ESDI, AT, ATI, etc.), how the drive came, such as with a controller and software, or just by itself, and how fast the drive could be read, the interleave factor. During that time, a healthy size drive was 150MB, small was 21MB and average was 40MB. DOS had a limitation to the partition size that just happened to fit the ST238. Seagate also brought out a big drive that was RLL, the ST4144R. It was the ST4096 with an RLL controller. The form factor on this drive was that it was full height, 5.25". Along with volume leader in drives at the time, the performance manufacturer was Maxtor. Other populare manufacturers that have gone by the wayside or have been taken over were Micropolis, Conner, Microscience, Miniscribe, Priam, Rodime, Imprimis and Control Data.


A computer industry acronym for Return Materials Authorization. You must have an RMA in order to return equipment for service, validation, upgrades, or exchange. Most companies track such returns by this number. See RA.


A computer and telephony acronym for Rack Mount Equipment. RME is equipment which is designed to mount in a standard steel framework consisting of parallel pairs of steel channel verticals spaced 19" and drilled for mounting screws. This is usually an industrial or test installation. See RMU.


RMI is a programming acronym for Remote Method Invocation. RMI is a way that a programmer, using the Java programming language and development environment, can write object-oriented programming in which objects on different computers can interact in a distributed network. RMI is the Java version of what is generally known as a remote procedure call (RPC), but with the ability to pass one or more objects along with the request. The object can include information that will change the service that is performed in the remote computer. Sun Microsystems, the inventors of Java, calls this "moving behavior." For example, when a user at a remote computer fills out an expense account, the Java program interacting with the user could communicate, using RMI, with a Java program in another computer that always had the latest policy about expense reporting. In reply, that program would send back an object and associated method information that would enable the remote computer program to screen the user's expense account data in a way that was consistent with the latest policy. The user and the company both would save time by catching mistakes early. Whenever the company policy changed, it would require a change to a program in only one computer. Sun calls its object parameter-passing mechanism object serialization. An RMI request is a request to invoke the method of a remote object. The request has the same syntax as a request to invoke an object method in the same (local) computer. In general, RMI is designed to preserve the object model and its advantages across a network. RMI is implemented as three layers. The three layers are:
1. A stub program in the client side of the client/server relationship, and a corresponding skeleton at the server end. The stub appears to the calling program to be the program being called for a service. (Sun uses the term proxy as a synonym for stub.)
2. A Remote Reference Layer that can behave differently depending on the parameters passed by the calling program. For example, this layer can determine whether the request is to call a single remote service or multiple remote programs as in a multicast.
3. A Transport Connection Layer, which sets up and manages the request.
A single request travels down through the layers on one computer and up through the layers at the other end. RMI is supplied as part of Sun Microsystem's Java Development Kit (JDK).


An acronym for Root Mean Square. This is simply a fancy way of describing the average voltage level of an audio signal.


An acronym for Rally Monkey Time. This is a call to arms for Los Angeles (Anaheim) Angels' fans; a specific time that puts FEAR in the hearts of other baseball teams. For a full RMT explanation, see our RM Time Display.


An acronym for Rack Mount Unit. See RME. A single RMU is 1.75 inches of vertical space in a rack housing. It is typically in the form of a number such as this; 4U, meaning 4 units or RMUs. A synonym is also an SRU. Please also see our Server Rack Unit Space Converter.


A telephony acronym for Ring, No Answer.


Computer shorthand for Really Nice Person. See CSGNetwork.

Road Trips & Tours

Road Trips are an ISP feature that allow you to take a trip around your service, computer or the Internet while spending time in a chat room. You can even create your own trips for others to join.


1. A device that responds to sensory input. They are often just called "Bots". See robotics.
2. A program that runs automatically without human intervention. Typically, a robot is endowed with some artificial intelligence so that it can react to different situations it may encounter. Two common types of robots are agents and spiders. See some of our own information about robots, or see the BOTSPOT website for excellent information on bots.


The field of computer science and engineering concerned with creating robots or bots, devices that can move and react to sensory input. Robotics is one branch of artificial intelligence. Robots are now widely used in factories to perform high-precision jobs such as welding and riveting. They are also used in special situations that would be dangerous for humans, for example, in cleaning toxic wastes or defusing bombs. Although great advances have been made in the field of robotics during the last decade, robots are still not very useful in everyday life, as they are too clumsy to perform ordinary household chores. The term robotics was coined by the writer Isaac Asimov. In his science fiction book I, Robot, published in 1950, he presented three laws of robotics:
1. A robot may not injure a human being, or, through inaction, allow a human being to come to harm.
2. A robot must obey the orders given it by human beings except where such orders would conflict with the First Law.
3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.


Rolling On (the) Floor Laughing. An example of online shorthand used in chat rooms, E-Mail, and instant messages.


1. A slang term, rollout is an orchestrated series of product related activities that are intended to accumulate meaning as they occur; Microsoft is famous for such events. Computer product makers and computer advertising marketers use the term to describe an ongoing series of related product announcements and events that are staged over time with the idea of keeping the name in mind. Public relations campaigns use the term to describe the revelation of a major company theme, such as Windows 2000 or Windows XP, an event, or other message over a period of time calculated to lead to sales results.
2. When a company installs new equipment into a major user's location, the installation staging and hype that goes with it is sometimes called a rollout.


Read Only Memory. ROM is a section of memory that is permanent and will not be lost when the computer is turned off. The computer's start-up instructions are stored in ROM. While ROM is actually a chip, hardware, it contains software.


1. The 'base' or bottom of a system. e.g. the 'root directory' is the lowest possible directory in a file system, and in X11 the 'root window' is the background on which all other windows are drawn.
2. In Unix, the user 'root' is the user that owns the system and has full superuser power.
3. The administrative user account on a UNIX system that can bypass security controls. Sysadmins will log in as root when they need to perform tasks such as modifying system files, creating new user accounts, or setting up new services. The root account is also known as the superuser account. Root passwords are closely guarded by security-conscious sysadmins. See also sysadmin. Also, slang for the lowest level of directory on a DOS system; Root Directory.

root directory

The top level in a hierarchical file system. For example on a PC, the root directory of your C: drive contains all the second-level subdirectories on that drive. See root


Rules of the Road, a set of guidelines for the use of some online services that is part of your ISP's Terms of Service.


Rolling On The Floor, Laughing, an example of online shorthand frequently used in E-Mail and chat rooms.


1. A computer or internetworking device that directs traffic and moves packets between networks. They can be of conventional network wiring architecture or wireless. A router is often confused with a bridge or gateway though routers are far more complex than either and usually considerably more expensive. A hardware architecture used in LANs, MANs, WANs, the Internet and Intranets. A device that connects any number of LANs. Routers use headers and a forwarding table to determine where packets go, and they use ICMP to communicate with each other and configure the best route between any two hosts. Very little filtering of data is done through routers; that is left to bridges. Routers do not care about the type of data they handle.
2. The device that connects multiple computer networks by reading OSI layer three addressing on incoming and outgoing packets. Packet information is read and the packets are then forwarded to the appropriate end station. A router can present multiple IP addresses within a network as the router's address to the outside world for security reasons. Hubs or switches can be in the router as well. There is often a firewall in them when used to connect to an outside network or the Internet.
3. Network layer device that uses one or more metrics to determine the optimal path along which network traffic should be forwarded. Routers forward packets from one network to another based on network layer information.
4. The most common usage in recent years for a router is to present an effective hardware firewall for home computer installations, one or multiple, for Internet broadband connectivity. This is the first line defense against hackers and privacy invaders for computers that are online all of the time. These types of routers are far less costly than major routers but just as effective at what they do.


A piece of a program that is "called" from another part of the
program. Often a well-structured program will consist of a short main routine that calls many other routines and subroutines to do the majority of work. Routines are individually tested sections of programming code and therefore, cut down the debugging and testing time when used and then used again in other situations. Routines can be actually small programs that do several jobs. They are smaller than a real program but larger than a subroutine. They can be made up of several subroutines.


Rockwell Protocol Interface, a type of modem that uses software as part of its operation. RPI
modems, also known as V. Fast Class modems, may need special settings to work properly with some online services. Many modem manufacturers use the Rockwell chipset. In some cases, RPI based modem need special initialization sequences to operate properly on the Internet. If you are not sure if you have an RPI based modem, issue a command, ATI3 and get the response from the modem. It will indicate the identity of the technology. If you do have RPI technology, you may want to check with you ISP to see if they require a special INIT command. This instruction set and the industry standard Hayes instruction set are NOT 100% compatible. Rockwell's website is HTTP://WWW.ROCKWELL.COM.


An electronics industry acronym for Rear Projection TV, a method of displaying the picture rather than a transmission protocol. The picture image is actually projected onto a screen (what the viewer sees) from behind the screen, as opposed to the projected image coming from the front of the screen. See
SDTV for more information.


In 1960, a national standards committee, today known as the Electronic Industries Association (now international), developed a common interface standard for data communications equipment. At that time, data communications was thought to mean digital data exchange between any centrally located mainframe computer and any remote computer terminal. It also could be possibly between two terminals without any computer involved. These devices were linked by telephone voice lines, and consequently required a modem at each end for signal translation. While simple in concept, the many opportunities for data error that occur when transmitting data through an analog channel require a relatively complex design. It was thought that a standard was needed first to ensure reliable communication, and second to enable the interconnection of equipment produced by different manufacturers, thereby fostering the benefits of mass production and competition. From the need for reliability, the RS-232 standard was born. It specified signal voltages, signal timing, signal function, a protocol for information exchange, and mechanical connectors. See our detailed
explanation of serial communications.


Real Soon Now.


See Rich Text Format.


Abbreviation for Read The Flipping Manual. You can safely assume that if you get this message, you have NOT been paid a compliment about the knowledge you have just displayed or the question you have asked; an inflammatory insult, deserved or not.


1. The copper, gold or silver conductive material etched into or scored onto circuit boards to allow electrical current to flow on the board. It is often covered by an insulating material.
2. The command given to execute a program or instruction.
3. An exercise that is not common among programmers.

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