Computer Terms Beginning with "R"

[MysteRy]

Source : PC.net

RADCAB

RADCAB is a mnemonic acronym that helps people evaluate information found online. It was created by Karen Christensson, a library media specialist, for helping students research topics on the Web. However, the acronym can be used by anyone who needs to look up information online.

Each letter of RADCAB represents a means of evaluating information:


Relevancy - Is the information relevant to my topic or research question?

Appropriateness - Is the information appropriate to my age and values?

Detail - Does the information contain enough detail for the subject I am researching?

Currency - How recently was the information written or published?

Authority - Who is the author and what are his or her credentials?

Bias - Is the information written only to inform or is it meant to be persuasive?


To learn more about RADCAB and its many uses, visit RADCAB.com.

[MysteRy]

RAID

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.

The benefits of RAID come from a technique called "striping," which splits up the stored data among the available drives. The "stripes" of data are usually a couple of megabytes large and are interleaved between the drives. The striping system also increases the mean time between failure (MTBF), when reading data. This allows more data to be read accurately in a short period of time. The benefits of the RAID system are especially noticeable when storing large amounts of data. Therefore, many Web hosting and Internet Service Providers use RAID to store data for their clients.

[MysteRy]

RAM

Stands for "Random Access Memory," and is pronounced like the male sheep. RAM is made up of small memory chips that form a memory module. These modules are installed in the RAM slots on the motherboard of your computer.

Every time 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 effectively speed up your computer. In fact, adding RAM can be more beneficial to your computer's performance than upgrading the CPU.

To check how much RAM a Windows computer has, open the "System" Control Panel. This can be done by right-clicking "My Computer" and selecting "Properties..." To view how much RAM is installed in a Macintosh computer, select "About This Mac" from the Apple Menu.

[MysteRy]

Raster Graphic

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.

Since raster graphics need to store so much information, large bitmaps require large file sizes. Fortunately, there are several image compression algorithms that have been developed to help reduce these file sizes. JPEG and GIF are the most common compressed image formats on the Web, but several other types of image compression are available.

Raster graphics can typically be scaled down with no loss of quality, but enlarging a bitmap image causes it to look blocky and "pixelated." For this reason, vector graphics are often used for certain images, such as company logos, which need to be scaled to different sizes.

[MysteRy]

Raw Data

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."

[MysteRy]

Raw File

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.

[MysteRy]

RDF

Stands for "Resource Description Framework." RDF is a specification that defines how metadata, or descriptive information, should be formatted. The RDF model uses a subject-predicate-object format, which is a standardized way of describing something. For example, an RDF expression may read, "The computer has a hard drive that stores 250GB." "The computer" is the subject, "has a hard drive that stores" is the predicate, and "250GB" is the object.

RDF formatting is used in RSS feeds, which contain short descriptions of Web pages. The RDF standard helps ensure each description contains the subject, predicate, and object necessary to describe the page's content. While humans do not require descriptions to be formatted in such a specific way (we would actually find it rather monotonous), computers benefit from the standard formatting. For example, it makes it easier for computer systems to sort and index RSS feeds based on the RDF descriptions. The end result is more accurate results when people search for articles using keywords.

[MysteRy]

RDRAM

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.

An improvement to RDRAM called Direct Rambus (DRDRAM) allows for even faster data transfer rates. DRDRAM uses a 16-bit bus rather than the 8-bit bus DRAM uses, which means it can handle 8 operations at once and can transfer data at a speeds of 1.6 GHz. Now that's fast.

[MysteRy]

Readme

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!

[MysteRy]

Real Number

Example: "Real numbers are sometimes described as points on an infinite number line."

Real numbers include all positive and negative numbers. They may be integers (e.g. -12), rational numbers (e.g. 9/10), or irrational numbers, (e.g. 1.4142135...). Numbers with decimal points are also called floating point numbers, since the decimal may also be referred to as a floating point. CPUs can process all types of real numbers, though most processors include a separate floating point unit, or FPU, for processing floating point calculations.

So if there are real numbers, do fake numbers exist? Well, considering that fake numbers, by definition, are not real, the answer is no. However, as many computer nerds know, it is still possible for someone to give you a fake phone number.

[MysteRy]

Real-Time

When an event or function is processed instantaneously, it is said to occur in real-time. To say something takes place in real-time is the same as saying it is happening "live" or "on-the-fly." For example, the graphics in a 3D action game are rendered in real-time by the computer's video card. This means the graphics are updated so quickly, there is no noticeable delay experienced by the user. While some computer systems may be capable of rendering more frames per second than other systems, the graphics are still being processed in real-time.

While video games often require real-time rendering, not all graphics are rendered in real-time. For example, some complex 3D models and animations created for movies are not rendered in real-time, but instead are pre-rendered on a computer system so they can be played back in real-time. As graphics cards get increasingly faster, they are capable of rendering some 3D animations in real-time that previously would need to be pre-rendered.

Real-time also describes the way streaming media is processed. Instead of waiting for a file to completely download, the information is played back as it is downloaded. This allows for news broadcasts, sound clips, and other streaming audio and video data to be played live from the Internet. Thanks to real-time processing, people can access information without having to wait for it. This is an important benefit since these days, anything that takes longer than 5 seconds seems like a long time.

[MysteRy]

Recursion

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.

[MysteRy]

Recursive Function

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.

[MysteRy]

Recycle Bin

Example: "If you want to delete items in Windows, drag them to the Recycle Bin."

The Recycle Bin in used by Windows computers to store deleted items. It temporarily stores files and folders before they are permanently deleted. You can open the Recycle Bin by double-clicking the icon on the Windows desktop. The Recycle Bin window allows you to delete items individually or restore them to their original location. If you want to permanently remove all items in the Recycle Bin, select "Empty the Recycle Bin" in the left sidebar of the window.

[MysteRy]

Refresh

Refresh is a command that reloads the contents of a window or Web page with the most current data. For example, a window may list files stored within a folder, but may not track their location in real-time. If the files have been moved or deleted since the window was first opened, the folder contents displayed will be inaccurate. By refreshing the window, a current list of files is displayed.

Web browsers include a Refresh command, which reloads the contents of a Web page. This is especially useful for dynamic Web pages, which contain content that changes often. For example, a page may include a stock quote, which is updated every few seconds. By refreshing the page, a user can see the latest quote and track how much the stock continues to drop since he bought it. Web developers may also use the Refresh command to view recently published changes to Web pages.

Since refreshing a window reloads it with new information, the terms "refresh" and "reload" are often used synonymously. In fact, some Web browsers, such as Firefox and Safari use the term "Reload" instead of "Refresh." In Windows, the shortcut key for the Refresh command is typically "F5," while on the Mac, the shortcut is often "Command-R."

The term "Refresh" may also refer to the redrawing process of a computer monitor. This process usually happens many times per second and is called the "refresh rate."