J277 Section 2 Data Representation

Binary

A base-2 numeral system that uses two symbols, typically 0 and 1, to represent data. It is the foundational language of computers and digital systems.

Bit

is the smallest unit of data in a computer, representing a binary value of either 0 or 1.

Nibble

a four-bit binary value, which can represent 16 different values ranging from 0 to 15.

Byte

a group of eight bits, commonly used to represent a single character of data in computing.

kB

A unit of digital information equal to 1000 bytes.

MB

A unit of digital information equal to 1000 kilobytes or 1,000,000 bytes.

GB

A unit of digital information equal to 1000 megabytes or 1,000,000,000 bytes.

TB

A unit of digital information equal to 1000 gigabytes or 1,000,000,000,000 bytes.

PB

A unit of digital information equal to 1000 terabytes or 1,000,000,000,000,000 bytes.

Denary

A base-10 numbering system used in everyday counting and mathematics, consisting of digits from 0 to 9.

Hexadecimal

A base-16 numbering system that uses digits 0-9 and letters A-F to represent values.

Binary to Denary Conversion

The process of converting numbers from the binary system (base-2) into the denary system (base-10) by calculating the sum of each binary digit multiplied by its corresponding power of two.

Denary to Binary Conversion

The process of converting numbers from the denary system (base-10) into the binary system (base-2) by repeatedly dividing the number by 2 and recording the remainders.

Binary to Hexadecimal Conversion

The process of converting numbers from the binary system (base-2) to the hexadecimal system (base-16) by grouping binary digits into sets of four and replacing each set with its hexadecimal equivalent.

Hexadecimal to Binary Conversion

The process of converting numbers from the hexadecimal system (base-16) to the binary system (base-2) by replacing each hexadecimal digit with its four-digit binary equivalent.

Denary to Hexadecimal Conversion

The process of converting numbers from the denary system (base-10) to the hexadecimal system (base-16) through repeated division by 16 and recording the remainders (or via conversion to binary first)

Hexadecimal to Denary Conversion

The process of converting numbers from the hexadecimal system (base-16) to the denary system (base-10) by multiplying each digit by 16 raised to the power of its position and summing the results.

Binary Addition

The process of adding binary numbers by carrying over values just like in decimal addition, following the rules of binary arithmetic.

Overflow

A condition that occurs in binary arithmetic when the result of an operation exceeds the maximum value that can be represented with a given number of bits, leading to incorrect results.

Binary Shift

A type of operation in binary arithmetic that involves shifting the bits of a binary number to the left or right, effectively multiplying or dividing the number by two.

Character set

A collection of characters that can be used in computing, including letters, numbers, and symbols, each represented by a unique binary code.

ASCII

A character encoding standard that uses 7 or 8 bits to represent text in computers, allowing for 128 or 256 different characters, including letters, numbers, and symbols.

Unicode

A character encoding standard that supports a vast range of characters from different languages and symbols, allowing for consistent representation and manipulation of text across different platforms.

Bitmap image

A type of image representation that uses a grid of pixels, where each pixel's color is defined by binary data, allowing for detailed images.

Vector image

A type of image representation that uses mathematical equations to define shapes and lines, allowing for scalable images without loss of quality.

Pixel

The smallest unit of a digital image or display, representing a single point of color. Pixels are combined to form images in raster graphics.

Resolution

The amount of detail an image holds, typically measured in pixels per inch (PPI) or dots per inch (DPI). Higher resolution means more detail and clarity in the image.

Image size

The dimensions of an image, usually measured in pixels, indicating its width and height. Image size can affect loading times and quality on different displays.

Colour depth

The number of bits used to represent the color of a single pixel in an image. Higher color depth allows for more colors and better image quality.

Factors affecting image quality

Elements such as resolution, image size, and color depth that influence the overall clarity, detail, and visual appeal of an image.

Image file size

The amount of digital storage space an image file occupies, typically measured in bytes, kilobytes, or megabytes. It is influenced by factors like image size and color depth.

Metadata

Information embedded in an image file that provides details about the image, such as its size, resolution, and colour depth. It can also include details about the camera settings, date taken, and location. .

Analogue sound

Sound represented by continuous waveforms, as opposed to digital signals. It captures sound in its natural form, often used in vinyl records and cassette tapes.

Digital

Representing data using discrete values, typically in binary format, allowing for easy manipulation and storage.

Analogue to Digital Converter

A device that converts analogue signals into digital data, enabling the processing and storage of sound or video in a digital format.

Amplitude

The height of a wave, representing the maximum extent of a vibration or oscillation, which correlates to the loudness of sound.

Frequency

The number of times a wave oscillates per second, measured in Hertz (Hz), which affects the pitch of sound.

Sample

The process of taking discrete measurements of an analogue signal at regular intervals to convert it into a digital format.

Sample Resolution

The detail or accuracy of a sample, determined by the number of bits used to represent each sample in digital audio, affecting sound quality.

Sample Rate

The number of samples taken per second from an analogue signal, typically measured in Hertz (Hz), which determines the quality and fidelity of the digital representation.

Sound file size

The amount of digital storage required for a sound file, determined by sample rate, sample resolution, and duration of the audio.

Compression

The process of reducing the size of a image or sound file by eliminating redundant data, which can affect quality depending on the compression method used.

Lossy Compression

A type of data compression that reduces file size by permanently eliminating certain information, particularly in audio and image files, which can result in a loss of quality.

Lossless Compression

A type of data compression that reduces file size without losing any information, ensuring that the original data can be perfectly reconstructed from the compressed data, commonly used for text and some image formats.

Lossy file types

File formats that utilize lossy compression, such as JPEG for images and MP3 for audio, resulting in reduced quality.

Lossless file types

File formats that use lossless compression, such as PNG for images and FLAC for audio, preserving original quality.