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What does digital mean?

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.From: Webopedia: http://webopedia.internet.com/TERM/d/digital.html
 
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.
From: Techweb: http://www.techweb.com/encyclopedia/
 
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.
From: Techweb: 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
From: Techweb: http://www.techweb.com/encyclopedia/
 
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.
From: Techweb: http://www.techweb.com/encyclopedia/

What are bits and bytes?

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
The combination of bits (which makes up one byte) below represents the letters below
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)
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

What does bitmap mean?

bitmap
A representation, consisting of rows and columns of dots, of a graphics image in computer memory. The value of each dot (whether it is filled in or not) is stored in one or more bits of data. For simple monochrome images, one bit is sufficient to represent each dot, but for colors and shades of gray, each dot requires more than one bit of data. The ore bits used to represent a dot, the more colors and shades of gray that can be represented.
The density of the dots, known as the resolution, determines how sharply the image is presented. This is often expressed in dots per inch (dpi ) or simply by the number of rows and columns, such as 640 by 480. To display a bit-mapped image on a monitor or to print it on a printer, the computer translates the bit map into pixels (for display screens) or ink dots (for printers). Optical scanners and fax machines work by transforming text or pictures on paper into bit maps. 
 
Bit-mapped graphics are often referred to as raster graphics. The other method for representing images is known as vector graphics or object-oriented graphics. With vector graphics, images are represented as mathematical formulas that define all the shapes in the image. Vector graphics are more flexible than bit-mapped graphics because they look the same even when you scale them to different sizes. In contrast, bit-mapped graphics become ragged when you shrink or enlarge them.
 
Fonts represented with vector graphics are called scalable fonts , outline fonts , or vector fonts. The best-known example of a vector font system is PostScript. Bit-mapped fonts, also called raster fonts, must be designed for a specific device and a specific size and resolution. 
From:Webopedia: http://webopedia.internet.com/TERM/b/bit_map.html

Formats for Graphics Files 
(When you create  a graphics file, the extension will relate to the format in which you saved it.  But just renaming the extension on a graphic will not change the graphic format.  You need to use a graphics program which embeds the appropriate formatting code in the file.)
Format Description
.bmp Bitmap - Microsoft Windows format.  For example, monitor background images are in .bmp format.
.gif Graphics Iinterchange Format - The bit-mapped file format used by CompuServe  and a standard form for Web icons, buttons and other non photo quality images.
.jpg  Joint Photographic Experts Group - a compression technique for color images. It can reduce files to approximately 5% of the original size; however, some definition is lost.  The picture is divided into tiny pixels, blocks, halved over and over, until the desired ratio is achieved.  The .jpg format is the standard for photo-type images on the Web. Compression saves memory and loading time.
.pcx A common graphics file format supported by many graphics programs.  Most scanners and fax modems also use this format.
.tif Tagged Image File Format - A standard file format for storing images as bit maps. It is used especially for scanned images because it can support any size, resolution, and color depth.
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