digit - A single character in a numbering system. In decimal, digits are 0 through 9. In binary, digits are 0 and 1. Describes any system based on discontinuous data or events. Computers are digital machines because at their most basic level they can distinguish between just two values, 0 and 1, or off and on. There is no simple way to represent all the values in between, such as 0.25. All data that a computer processes must be encoded digitally, as a series of zeroes and ones. The opposite of digital is analog. A typical analog device is a clock in which the hands move continuously around the face. Such a clock is capable of indicating every possible time of day. In contrast, a digital clock is capable of representing only a finite number of times (every tenth of a second, for example). In general, humans experience the world analogically. Vision, for example, is an analog experience because we perceive infinitely smooth gradations of shapes and colors. Most analog events, however, can be simulated digitally. Photographs in newspapers, for instance, consist of an array of dots that are either black or white. From afar, the viewer does not see the dots (the digital form), but only lines and shading, which appear to be continuous. Although digital representations are approximations of analog events, they are useful because they are relatively easy to store and manipulate electronically. The trick is in converting from analog to digital, and back again. 

This is the principle behind compact discs (CDs). The music itself exists in an analog form, as waves in the air, but these sounds are then translated into a digital form that is encoded onto the disk. When you play a compact disc, the CD player reads the digital data, translates it back into its original analog form, and sends it to the amplifier and eventually the speakers. 

Internally, computers are digital because they consist of discrete units called bits that are either on or off. But by combining many bits in complex ways, computers simulate analog events. In one sense, this is what computer science is all about. 
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digital

Traditionally, digital means the use of numbers and the term comes from digit, or finger. Today, digital is synonymous with computer. 

Digital Means Original The 0s and 1s of digital data mean more than than just on and off. They mean perfect copying. When information, music, voice and video are turned into binary digital form,
they can be electronically manipulated, preserved and regenerated perfectly at high
speed. The millionth copy of a computer file is exactly the same as the original. While
this continually drives the software industry crazy protecting its copyrights, it is nevertheless a major advantage of digital processing. 
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digital audio

Sound waves that have been digitized and stored in the computer. The most common digital audio formats are music CDs and Windows WAV files. Music CDs are played in CD players as well as CD-ROM readers. WAV files are stored in the computer or on  CD-ROMs and played by a media player software application. Although also in digital form and stored in the computer, MIDI music is not considered digital audio. MIDI files contain a coded version of the musical score, not the actual sound. (http://www.techweb.com/encyclopedia/)

digerati

The "digital elite." People that are extremely knowledgeable about computers. It often refers to the movers and shakers in the industry. Digerati is the high-tech equivalent of "literati," which refers to scholars and highly educated individuals.
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digitize

To translate into a digital form. For example, optical scanners digitize images by translating them into bit maps. It is also possible to digitize sound, video, and any type of movement. In all these cases, digitization is performed by sampling at discrete intervals. To digitize sound, for example, a device measures a sound wave's amplitude many times per second. These numeric values can then be recorded digitally.
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BITS AND BYTES

Bit stands for binary digit: 0 or 1 

A byte is made up of 8 bits

It takes 1 byte to store one ASCII character

ASCII stands for the American Standard Code for Information Interchange

Below are the digital representations for the letters A, B and C:

A 0100 0001
B 0100 0010
C 0100 0011

K stands for kilo and = 1024 (2 to the tenth power)

M stands for mega. A MB, megabyte is about a million bytes (1024x1024)

G stands for giga. A GB, gigabyte is about a billion bytes (1024x1024x1024)

T stands for tera. A TB, terabyte is about a trillion!

RAM is usually measured in MB

Hard disk spaces is usually measured in gigabytes

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Common formats for digital graphics files