Rational Number Definition A rational number is any number that can be expressed as a ratio of two integers (hence the name "rational"). It can be written as a fraction in which the the top number (numerator) is divided by the bottom number (denominator). All integers are rational numbers since they can be divided by 1, which produces a ratio of two integers. Many floating point numbers are also rational numbers since they can be expressed as fractions. For example, 1.5 is rational since it can...

Grayscale Definition Grayscale is a range of monochromatic shades from black to white. Therefore, a grayscale image contains only shades of gray and no color. While digital images can be saved as grayscale (or black and white) images, even color images contain grayscale information. This is because each pixel has a luminance value, regardless of its color. Luminance can also be described as brightness or intensity, which can be measured on a scale from black (zero intensity) to white (full inte...

Hexadecimal Definition Hexadecimal is a base-16 number system. It is a different method of representing numbers than the base-10 system we use in every day practice. In base-10, we count in multiples of 10 before adding another digit. For example, "8 - 9 - 10 - 11 - 12..." and "98 - 99 - 100 - 101 - 102..." Notice how a new digit is added when the number 10 is reached, and another digit is added to represent 100 (10x10). In base-16, or the hexadecimal number system, each digit can have sixteen v...

MHL Definition Stands for "Mobile High-definition Link." MHL is a technology designed for connecting mobile devices, such as smartphones and tablets, to TVs, displays, home theater systems, and automotive interfaces. It was developed and standardized by multiple companies that make up the MHL Consortium. These include Nokia, Samsung, Sony, Toshiba, and Lattice Semiconductor. An MHL connection provides three primary functions: It transmits a full HD audio and video signal It provides electr...

Pixel Definition The term "pixel" is actually short for "Picture Element." These small little dots are what make up the images on computer displays, whether they are flat-screen (LCD) or tube (CRT) monitors. The screen is divided up into a matrix of thousands or even millions of pixels. Typically, you cannot see the individual pixels, because they are so small. This is a good thing, because most people prefer to look at smooth, clear images rather than blocky, "pixelated" ones. However, if you s...

LPI Definition Stands for "Lines Per Inch." LPI is used to measure the resolution of images printed in halftones. Because halftone images are printed as a series of dots, the higher the LPI number, the more dense the dots can be, resulting in a finer resolution. Newspapers are typically printed in a resolution of 85 lpi, while magazines may use 133 lpi or higher. Because the naked eye can distinguish halftone dots up to about 120 lpi, you are more likely to notice the dots in newspaper print th...

Dithering Definition Dithering is a process that uses digital noise to smooth out colors in digital graphics and sounds in digital audio. Digital Graphics All digital photos are an approximation of the original subject, since computers cannot display an infinite amount of colors. Instead, the colors are estimated, or rounded to the closest color available. For example, an 8-bit GIF image can only include 256 (2^8) colors. This may be enough for a logo or computer graphic, but is too few colors...

ISO Definition Stands for "International Organization for Standardization." Yes, technically the acronym should be "IOFS," but I guess ISO sounds better. The ISO works with standards institutes from over 150 countries to develop technology and product standards. These standards lead to a more efficient, safer, and cleaner development of products. It also leads to more standardized products for consumers. The ISO is important to the computer industry, since the organization standardizes many of ...

Typeface Definition A typeface is a set of characters of the same design. These characters include letters, numbers, punctuation marks, and symbols. Some popular typefaces include Arial, Helvetica, Times, and Verdana. While most computers come with a few dozen typefaces installed, there are thousands of typefaces available. Because they are vector-based (not bitmaps), typefaces can be scaled very large and still look sharp. The term "typeface" is often confused with "font," which is a specific s...

JFS Definition Stands for "Journaled File System." JFS is a 64-bit file system created by IBM. The initial version of JFS (also called JFS1) was developed for IBM's AIX operating system and was released in 1990. In 2001, IBM released JFS2 (the Enhanced Journaled File System), as well as a version of JFS that is compatible with the Linux operating system. The "journaled" aspect of JFS means that the file system keeps tracks of changes to files and folders in a log file (or journal). This log can...