What is RAID?
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Stands for "Redundant Array of Independent Disks." RAID is a method of storing data on multiple hard disks. When disks are arranged in a RAID configuration, the computer sees them all as one large disk. However, they operate much more efficiently than a single hard drive. Since the data is spread out over multiple disks, the reading and writing operations can take place on multiple disks at once. This can speed up hard drive access time significantly. Multiple hard drives may not improve hard disk performace as much as multiple processors may enhance the CPU performance, but it is based on a similar logic.
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What is RAM?
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Stands for "Random Access Memory," and is pronounced like the male sheep. RAM is made up of small memory chips that are connected to the motherboard of your computer. Everytime you open a program, it gets loaded from the hard drive into the RAM. This is because reading data from the RAM is much faster than reading data from the hard drive. Running programs from the RAM of the computer allows them to function without any lag time. The more RAM your computer has, the more data can be loaded from the hard drive into the RAM, which can help speed up your computer. In fact, adding RAM can be more beneficial to your computer's performance than upgrading the CPU.
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What is Raster Graphic?
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Most images you see on your computer screen are raster graphics. Pictures found on the Web and photos you import from your digital camera are raster graphics. They are made up of grid of pixels, commonly referred to as a bitmap. The larger the image, the more disk space the image file will take up. For example, a 640 x 480 image requires information to be stored for 307,200 pixels, while a 3072 x 2048 image (from a 6.3 Megapixel digital camera) needs to store information for a whopping 6,291,456 pixels.
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What is Raw Data?
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Raw data is unprocessed computer data. This information may be stored in a file, or may just be a collection of numbers and characters stored on somewhere in the computer's hard disk. For example, information entered into a database is often called raw data. The data can either be entered by a user or generated by the computer itself. Because it has not been processed by the computer in any way, it is considered to be "raw data." To continue the culinary analogy, data that has been processed by the computer is sometimes referred to as "cooked data."
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What is Raw File?
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A raw file is a collection of unprocessed data. This means the file has not been altered, compressed, or manipulated in any way by the computer. Raw files are often used as data files by software programs that load and process the data. A popular type of raw file is "Camera RAW," which is generated by a digital camera. Instead of processing the image captured by the camera, the data is left unprocessed and uncompressed until it is opened with a computer program.
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What is RDRAM?
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Stands for "Rambus Dynamic Random Access Memory." It is a type of RAM made by Rambus (big surprise) and is the fastest type of computer memory available. Typical SDRAM can transfer data at speeds up to 133 MHz, while standard RDRAM can crank it up over 1 GHz. Though some motherboards can use RDRAM as system memory, it is so fast, most boards cannot fully benefit from the speed. Because of this, RDRAM is typically used for video memory on graphics acclerator cards, for cache memory (located on the CPU), and for system memory in high-performance workstations and servers.
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What is Readme?
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A readme file, often named "READ ME" to get the user's attention, is a text file containing useful information about a software program. It often accompanies the program's installer or is installed with the program. A typical readme file contains instructions on how to install the program, how to use the basic functions of the program, and what the program does. It may also include a list of recent updates made to the program. Sometimes the readme file will include warnings and other important notices regarding the operation of the program. So when you see a readme file accompanying a new software program, it is best to do what the file says and read it!
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What is Reciprocal Link?
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A reciprocal link is a mutual link between two objects, commonly between two websites in order to ensure mutual traffic.
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What is Recursion?
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Recursion is a process in which a function calls itself as a subroutine. This allows the function to be repeated several times, since it calls itself during its execution. Functions that incorporate recursion are called recursive functions.
Recursion is often seen as an efficient method of programming since it requires the least amount of code to perform the necessary functions. However, recursion must be incorporated carefully, since it can lead to an infinite loop if no condition is met that will terminate the function.
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What is Recursive Function?
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A recursive function is a function that calls itself during its execution. This enables the function to repeat itself several times, outputting the result and the end of each iteration. Below is an example of a recursive function.
function Count (integer N)
if (N <= 0) return "Must be a Positive Integer";
if (N > 9) return "Counting Completed";
else return Count (N+1);
end function
The function Count() above uses recursion to count from any number between 1 and 9, to the number 10. For example, Count(1) would return 2,3,4,5,6,7,8,9,10. Count(7) would return 8,9,10. The result could be used as a roundabout way to subtract the number from 10.
Recursive functions are common in computer science because they allow programmers to write efficient programs using a minimal amount of code. The downside is that they can cause infinite loops and other unexpected results if not written properly. For example, in the example above, the function is terminated if the number is 0 or less or greater than 9. If proper cases are not included in the function to stop the execution, the recursion will repeat forever, causing the program to crash, or worse yet, hang the entire computer system.
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What is Referrer?
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When visiting a webpage, the referer (sic) or referring page is the URL of the previous webpage from which a link was followed. More generally, it is the URL of a previous item which led to this request - the referer for an image, for example, is generally the HTML page on which it is to be displayed. The referer is part of the HTTP request sent by the browser program to the web server.
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What is Refresh Rate?
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Computer monitors often have a "maximum refresh rate" listed in their technical specifications. This number, measured in hertz (Hz), determines how many times the screen is redrawn each second. Typical refresh rates for CRT monitors include 60, 75, and 85 Hz. Some monitors support refresh rates of over 100 Hz.
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What is Registry?
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This is a database used by Microsoft Windows to store configuration information about the software installed on a computer. This information includes things like the desktop background, program settings, and file extension associations.
The Windows registry consists of the following six parts:
HKEY_User - contains the user information for each user of the system.
HKEY_Current_User - has all the preferences for the current user.
HKEY_Current_Configuration - stores settings for the display and printers.
HKEY_Classes_Root - includes file associations and OLE information.
HKEY_Local_Machine - has the settings for the hardware, operating system, and installed applications.
HKEY_Dyn_Data - includes performance data.
When you install a program, it will usually write some data to the computer's registry. If you want to manually edit the registry for some reason, you can use the "regedit.exe" program, which comes with the Windows operating system. However, you should not edit the registry if you don't know what you're doing because it could disable your computer.
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What is Remote Access?
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Remote access is just what it sounds like -- the ability to access your computer from a remote location. Programs like PC Anywhere (Windows), Remote Access (Mac), and Timbuktu (Windows and Mac) allow users to control remote computers from their local machine. In order for a remote access connection to take place, the local machine must have the remote client software installed and the remote machine must have the remote server software installed. Also, a username and password is almost always required to authenticate the connecting user.
Remote access is more than just being able to connect to a remote machine -- it is the ability to control the machine once the connection has been made. A remote access program can basically transform your local computer into the the remote computer you connect to. This is great for people who sometimes work from home and for server administrators who frequently need to update and make changes on their server machines. Most remote access programs also allow users to transfer files between the local and remote machines, which can save a lot of commuting time. While remote access can be helpful for many people, don't enable it on your machine unless you absolutely need to. It is just one more security concern you will have to deal with.
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What is Remote User?
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A "remote user" is how a woman might refer to her husband while he is watching TV. In the computer world, however, a remote user is someone who works on a computer from a remote location. For example, if Bob leaves work and forgets to bring a file with him from his office computer, he might be able to connect to his work machine from his home computer and grab the file. When Bob accesses his office computer from home, he is considered a remote user.
Of course, Bob does not want anyone to be able to access his computer remotely. So, he would most likely need to enter a username and password in order to connect to his office machine. Programs like Timbuktu and PC Anywhere allow users to not only connect to their computers remotely, but actually display the interface of the remote machine on their local computer. Unix-based systems such as Mac OS X and Linux allow users to control the computers remotely using the text-based "Terminal" interface. Remote connections can be made over a local network, a direct phone connection, or over the Internet. Of course, the slower the connection, the slower the response time will be from the remote computer.
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What is Resolution?
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This term can describe either how many pixels a monitor can display or how fine a printer can print.
1. Monitors. A small monitor may have a resolution or 640 x 480, which means there are 640 pixels horizontally across the screen and 480 pixels vertically. Some other common monitor resolutions are 800 x 600, 1,024 x 768, and 1,280 x 1,024. The higher the resolution, the more that can be displayed on the screen.
2. Printers. Printer resolution measures how fine a printer can print. This measurement is known as dots per inch, or "dpi." The greater the dpi, the better the image clarity. Scanner resolution is also measured in dpi.
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What is RGB?
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Stands for "Red Green Blue." It refers to the three hues of light (red, green, and blue, for those of you that are a little slow), that can mix together to form any color. When the highest intensity of each color is mixed together, white light is created. When each hue is set to zero intensity, the result is black. TVs and computer monitors use RGB to create the colorful images you see on the screen. In print, however, the 4 colors -- cyan, yellow, magenta, and black (CYMK) -- are used to create color images.
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What is Rich Text?
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Rich text is more exciting than plain text. It supports text formatting, such as bold, italics, and underlining, as well as different fonts, font sizes, and colored text. Rich text documents can also include page formatting options, such as custom page margins, line spacing, and tab widths.
Most word processors, such as Microsoft Word, Lotus Word Pro, and AppleWorks, create rich text documents. However, if you save a document in a program's native format, it may only open with the program that created it. For example, Lotus Word Pro will not be able to open an AppleWorks text document, even though both programs are text editors. This is because each program uses its own method of formatting and creating text files.
The good news is, most word processors allow you to save rich text documents in the generic Rich Text Format. This file format, which uses the .RTF extension keeps most, if not all the text formatting. However, because it is a standard format, it can be opened by just about any word processing program and even most basic text editors.
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What is Right Click?
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Most computer mice have at least two mouse buttons. When you press the left one, it is called a left click. When you press the one on the right, it is called a right click. By default, the left button is the main mouse button, and is used for common tasks such as selecting objects and double-clicking.
The right mouse button is often used to open contextual menus, which are pop-up menus that change depending where you click. For example, if you right click on the desktop, you may see a menu pop up that includes "Change View Options" and "Change Desktop Background." If you right click on a folder, the menu might include options such as "Open" and "Properties." Certain programs, such as video games, may use the right click to perform other functions, such as firing a secondary weapon in a first-person shooter. Most programs, however, use the right click to open contextual menus.
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What is Ripcording?
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Recording audio with a computer involves capturing an audio signal and saving it digitally on a hard drive. Ripping an audio track is the process of converting an audio file to an MP3 or other compressed audio format. Ripcording is the simultaneous recording and ripping of an audio signal.
Ripcording is a popular way to download and archive Internet radio broadcasts, digital cable TV radio, and satellite radio. All you need is ripcording software that will record audio and compress it at the same time. By ripcording live audio, you can save audio streams on your hard drive and listen to them whenever you want.
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What is RISC?
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Stands for "Reduced Instruction Set Computing,"and is pronounced "risk." It is arguably the fastest and most effiecient microprocessor technology available today. The RISC architechture is an improvement upon the CISC (Complex Instruction Set Computing) architecture used in the original Intel Pentium chips. In 1974, John Cocke of IBM Research was working on making a faster version of the CISC chip and came up with a design that significantly reduced the number of instructions need for performing computations. The new design was not only faster than the CISC architecture, but the chips were also smaller and less expensive to manufacture. Motorola's PowerPC chips (such as the G4 in Power Macs) are the most widely used RISC-based chips. Intel has slowly been integrating RISC technology into its chips, but they still are mostly CISC-based.
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What is Robots.txt?
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The robots exclusion standard or robots.txt protocol is a convention to prevent well-behaved web spiders and other web robots from accessing all or part of a website. The information specifying the parts that should not be accessed is specified in a file called robots.txt in the top-level directory of the website.
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What is ROM?
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Stands for "Read-Only Memory." Please do not confuse this term with RAM or a hard drive, as many people already do. ROM is memory containing hardwired instructions that the computer uses when it boots up, before the system software loads. In PCs, the instructions are read from a small program in the ROM, called the BIOS (Basic Input/Output System).
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What is Root?
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This computer term actually has nothing to do with trees or root beer. Instead, it is commonly used in reference to a computer's directory structure. The root directory is the top-level directory of a file system. For example, on a Windows-based PC, "C:\" would be the root directory of the C drive. On a Web server, the root directory is usually designated by just a forward slash ("/ "). So, on a Unix system, you would type "cd /" (change directory to root) to go to the root directory. Root is also the name of the user who has complete administrative privleges on a Unix or Linux server. While most users can only access their own directory (i.e. "/www/users/~fred/"), the root user can access any folder from the root directory down. This allows the root user to make system changes such as modifying the permissions of other users without telling them.
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What is Router?
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This is a hardware device that routes data (hence the name) from a local area network (LAN) to another network connection. A router acts like a coin sorting machine, allowing only authorized machines to connect to other computer systems. Most routers also keep log files about the local network activity.
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What is RSS?
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Stands for "RDF Site Summary," but is commonly referred to as "Really Simple Syndication." RSS is method of providing website content such as news stories or software updates in a standard XML format. Websites such as The Wall Street Journal and CNET's News.com provide news stories to various RSS directories that distribute them over the Internet. RSS content can be accessed with an RSS-enabled Web browser or other programs designed for retrieving RSS feeds.
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What is RTF?
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Stands for "Rich Text Fomat." This is a file format standardized by Microsoft for creating formatted text files. Unlike a basic text file, an RTF file can include information such as text style, size, and color. The nice thing about the RTF format is that it is a universal format, meaning it can be read by nearly all word processors.
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What is Runtime?
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When a program is running, or executing, it is said to be in runtime. The term is mostly used by software developers to specify when errors in a program occur. A "runtime error" is an error that happens while the program is executing. For example, if a program told you that 2 + 2 was 5000, that would be a runtime error. A memory leak, where the program sucks up excessive amounts of system memory is also a runtime error. The other major type of program error is a compile-time error, where the application will not even compile into an executable program. Examples of compile-time errors are syntax errors in the program code and file linking errors. Runtime is a good term to know, but you most likely won't hear it used very often unless you like to hang out with computer nerds.
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What is RUP?
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Stands for "Rational Unified Process." RUP is a software development process from Rational, a division of IBM. It divides the development process into four distinct phases that each involve business modeling, analysis and design, implementation, testing, and deployment. The four phases are:
Inception - The idea for the project is stated. The development team determines if the project is worth pursuing and what resources will be needed.
Elaboration - The project's architecture and required resources are further evaluated. Developers consider possible applications of the software and costs associated with the development.
Construction - The project is developed and completed. The software is designed, written, and tested.
Transition - The software is released to the public. Final adjustments or updates are made based on feedback from end users.
The RUP development methodology provides a structured way for companies to envision create software programs. Since it provides a specific plan for each step of the development process, it helps prevent resources from being wasted and reduces unexpected development costs.
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