Jargon Buster

Rack Unit

is the space used by company’s server(s) is measured in Rack Units (or 'U'). This is the unit of measurement used for defining the vertical space used. A 'U' is equivalent to 1.75 inches (4.45cm). A full rack contains 40 to 42U

Radio button

A method of selecting an option in an application dialogue box. Only one button in the control group can be selected: if you change your selection, your first choice is automatically deselected.

RAID

In computing, a Redundant Array of Independent Disks, also known as Redundant Array of Inexpensive Disks (commonly abbreviated RAID) is a system which uses multiple hard drives to share or replicate data among the drives. Depending on the version chosen, the benefit of RAID is one or more of increased data integrity, fault-tolerance, throughput or capacity compared to single drives. In its original implementations (in which it was an abbreviation for "redundant array of inexpensive disks"), its key advantage was the ability to combine multiple low-cost devices using older technology into an array that offered greater capacity, reliability, speed, or a combination of these things, than was affordably available in a single device using the newest technology.

RAID 0

A RAID 0 (also known as a striped set) splits data evenly across two or more disks with no parity information for redundancy. RAID 0 is normally used to increase performance, although it can also be used as a way to create a small number of large virtual disks out of a large number of small physical ones.

RAID 1

A RAID 1 creates an exact copy (or mirror) of a set of data on two or more disks. This is useful when read performance is more important than minimizing the storage capacity used for redundancy. The array can only be as big as the smallest member disk, however. A classic RAID 1 mirrored pair contains two disks, which increases reliability by a factor of two over a single disk, but it is possible to have many more than two copies. Since each member can be addressed independently if the other fails, reliability is a linear multiple of the number of members. To truly get the full redundancy benefits of RAID 1, independent disk controllers are recommended, one for each disk.

RAID 2

A RAID 2 stripes data at the bit (rather than block) level, and uses a Hamming code for error correction. The disks are synchronized by the controller to run in perfect tandem. This is the only original level of RAID that is not currently used. Extremely high data transfer rates are possible.

RAID 3

A RAID 3 uses byte-level striping with a dedicated parity disk. RAID 3 is very rare in practice. One of the side effects of RAID 3 is that it generally cannot service multiple requests simultaneously. This comes about because any single block of data will by definition be spread across all members of the set and will reside in the same location, so any I/O operation requires activity on every disk.

RAID 5

A RAID 5 uses block-level striping with parity data distributed across all member disks. RAID 5 has achieved popularity due to its low cost of redundancy. Generally RAID 5 is implemented with hardware support for parity calculations.

RAM

Random Access Memory is the computer's main memory, which it uses to hold whatever you are currently working on. The contents of RAM are lost when the computer is switched off

Range

In a spreadsheet, a defined block of cells. Rather than performing calculations on each cell individually, you can apply a formula to the whole range.

Readme file

A file created during an application installation that contains useful information. Readme files are usually found in the same Program Files folder as the application

Real time

Something that takes place on a computer at the same speed as it would in real life. In real-time games perhaps a flight simulator a minute or an hour of game time is the same as in the outside world. In real time graphics processing, the onscreen image or video is rendered as you watch, rather than relying on a pre-recorded picture.

Reboot

To restart a computer. Normally, this is by using the 'Restart' option on the Windows Start menu. However, it may be necessary to press Control-Alt-Delete or even to use the Reset button if one is fitted to the PC.

Record

A single entry in a database, comprising a related group of individual 'fields'. Each entry in an address book, for example, is a record.

Registry

A database integrated into Windows which stores information on all hardware and software installed on your PC. This includes user preferences, settings and licence information.

Remote Hands

is if the company requires something to be done to the server, they pay for Remote Hands support and are given remote (over the internet) access to their servers

Resolution

The amount of detail shown in an image, whether on screen or printed. For a monitor, it is the number of pixels it can display (typically 1024 x 768 pixels for a 17in monitor). For printers and scanners, resolution is measured in dots per inch (dpi); the number of drops of ink or toner that can be printed in a square inch.

REST

Representational State Transfer (REST) is a software architectural style for distributed hypermedia systems like the world wide web. The term originated in a 2000 doctoral dissertation about the web written by Roy Fielding, one of the principal authors of the HTTP protocol specification, and has quickly passed into widespread use in the networking community.

While REST originally referred to a collection of architectural principles (described below), people now often use the term in a looser sense to describe any simple web-based interface that uses XML and HTTP without the extra abstractions of MEP-based approaches like the web services SOAP protocol. It is possible to design web service systems in accordance with Fielding's REST architectural style, and it is also possible to design simple XML+HTTP interfaces in accordance with the RPC style but without actually using SOAP. These two different uses of the term REST cause some confusion in technical discussions, even though RPC is not an example of REST.

RFID

Radio Frequency Identification (RFID) is a automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. Two types of RFID tags exist, passive and active tags. Passive tags require no internal power source, whereas active tags require a power source. RFID is used in a plethora of applications, including transport toll tagging, product tracking, inventory systems, ticketing systems and animal and human implants.

RIA

Rich Internet Applications (RIA) are web applications that have the features and functionality of traditional desktop applications. RIA's typically transfer the processing necessary for the user interface to the web client but keep the bulk of the data (i.e maintaining the state of the program, the data etc) back on the application server.

Right-click

Most actions in Windows are performed by clicking the left mouse button. However, since the arrival of Windows 95, many programs and Windows itself make use of the right mouse button click to display a pop-up menu with special functions.

RJ-11

The type of small plug and socket used by modems to connect to a telephone socket. A converter plug is needed before an RJ-11 cable can be plugged into a standard UK telephone socket.

ROM

Read Only Memory - examples included CD-ROMS, DVDs, etc. memory storage that cannot be overwritten - just read

Router

is a device or, in some cases, software in a computer, that determines the next network point to which a packet should be forwarded toward its destination. The router is connected to at least two networks and decides which way to send each information packet based on its current understanding of the state of the networks it is connected to

RPC

Remote Procedure Call (RPC) is a protocol that allows a computer program running on one computer to cause a subroutine on another computer to be executed without the programmer explicitly coding the details for this interaction. When the software in question is written using object-oriented principles, RPC may be referred to as remote invocation or remote method invocation.

RSA

An internet encryption and authentication system that uses an algorithm developed in 1977 by Ron Rivest, Adi Shamir, and Leonard Adleman. The RSA algorithm is the most commonly used encryption and authentication algorithm and is included as part of the Web browser from Netscape and Microsoft. It's also part of Lotus Notes, Intuit's Quicken, and many other products.

RTC

Real-time clock. The battery-powered clock inside every PC which keeps track of time while the system is switched off.

RTE

Rich Text Editor is a What You See Is What You Get (WYSIWYG) Hyper Text Transport Protocol (HTML) editing component that runs in a web browser using the Microsoft Dynamic Hyper Text Markup Language (DHTML) Editing Control. This control allows anyone to edit HTML quickly and easily without any knowledge of the HTML language

RTF

Rich Text Format. A common file format used to transfer files between different word-processing programs. It preserves most of the formatting of a document.