Understanding Digital Data and Its Representation

Data compression

Any technique that recodes the data in a file so that it contains fewer bits.

Binary number system

A system that only has two digits, 0 and 1.

Unicode

Uses sixteen bits and provides codes for 65,000 characters.

UTF-8

A variable-length coding scheme that uses seven bits for common ASCII characters.

ASCII text

Plain unformatted text sometimes referred to as _______.

OCR

Optical character recognition, a process that interprets individual characters during or after a scan.

Lossless compression

Provides a way to compress data and reconstitute it into its original state.

Lossy compression

Throws away some of the original data during the compression process.

Digital content

A compilation of data such as eBooks, documents, images, music, and video.

Data

Symbols that represent people, events, things, and ideas.

Data representation

The form in which data is stored, processed, and transmitted.

Digital data

Text, numbers, graphics, sound, and video that have been converted into discrete digits such as 0s and 1s.

Analog data

Data represented using an infinite scale of values.

Binary

A system with only two possible states.

Digitization

The process of converting information into digital data that can be manipulated by electronic devices.

Bit

A 0 or 1 used in the digital representation of data.

File

A named collection of data that exists on a storage medium, like a hard disk, CD, or flash drive.

File name extension

A suffix such as .mp3 that can be appended to the end of the file name after a period.

Numeric data

Consists of numbers that can be used in arithmetic operations.

Character data

Composed of letters, symbols, and numerals that are not used in calculations.

ASCII

American Standard Code for Information Interchange, requiring seven bits for each character.

Extended ASCII

A superset of ASCII that uses eight bits for each character.

Byte

A group of eight bits, usually abbreviated as an uppercase B.