Glossary

Random Access Memory, one of two basic types of memory. Portions of programs are stored in RAM when the program is launched so that the program will run faster. Though a PC has a fixed amount of RAM, only portions of it will be accessed by the computer at any given time. Also called memory.

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.

File extensions: .BMP, .TIF, .GIF, .JPG

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.

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.

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.

Using the right mouse button to open context-sensitive drop-down menus.

Read-Only Memory, one of two basic types of memory. ROM contains only permanent information put there by the manufacturer. Information in ROM cannot be altered, nor can the memory be dynamically allocated by the computer or its operator.