Computer Science: Number Systems and Data Representation

This set of flashcards covers vocabulary from Lecture 1.1 through 1.7, including binary and hexadecimal number systems, computer arithmetic, negative number representation, data units, multimedia representation, and compression techniques.

Binary System

A base $2$ number system that represents data using two digits, $0$ (off) and $1$ (on), which correspond to the state of tiny switches in a computer.

Denary System

A base $10$ number system that uses the digits $0, 1, 2, 3, 4, 5, 6, 7, 8, 9$ to represent values.

Hexadecimal System

A base $16$ number system that uses $16$ digits ($0$ to $9$ and $A$ to $F$) to represent values, where one hex digit is equivalent to four binary digits.

Bit

The basic unit of all computing memory storage, which can be either a $1$ or a $0$.

Byte

The smallest unit of memory in a computer, consisting of $8$ bits.

Nibble

A unit of data storage that consists of $4$ bits.

Overflow Error

An error that occurs when a calculation produces a result that is too large to be stored in the available number of bits, such as an 8-bit register generating a 9th bit.

Binary Shifting

A process used by a CPU to perform multiplication (shifting bits left) and division (shifting bits right).

Two's Complement

A method for representing negative numbers in binary where the leftmost bit is treated as a sign bit ($1$ for negative, $0$ for positive).

Kibibyte (KiB)

A unit of data measurement equal to $2^{10}$ or $1024$ bytes.

Mebibyte (MiB)

A unit of data measurement equal to $2^{20}$ or $1048576$ bytes.

MAC Address

A unique identifier assigned to a device on a network, linked to the Network Interface Card (NIC) within the device.

IP Address

A unique identifier assigned to every device on a network; examples include IPv4 (a $32$-bit number) and IPv6 (a $128$-bit number).

Character Set

A list of characters defined by computer hardware and software that allows the computer to understand human characters, such as letters and punctuation.

ASCII

A character set that uses $7$ bits to represent $128$ different characters including English letters, digits, and punctuation marks.

Unicode

A character encoding standard that uses $16$ bits to support over $65000$ characters, covering virtually all languages, emojis, and symbols worldwide.

Digital Sample

A digital recording of an analog sound wave created by measuring the amplitude at regular intervals.

Sampling Resolution

The number of bits used to represent the amplitude of sound in a digital recording, also known as bit depth.

Sample Rate

The number of sound samples taken per second, measured in Hertz ($Hz$).

Bitmap Image

An image consisting of a grid of pixels where each pixel is stored as a sequence of binary numbers.

Pixel

The individual grid elements arranged in two dimensions that make up an image.

Colour Depth

The number of bits used to represent each colour in an image; for example, a $24$-bit depth allows for over $16$ million colours.

Image Resolution

The total number of pixels that make up a single image.

Lossy Compression

A file compression algorithm that reduces size by permanently eliminating unnecessary data, meaning the original cannot be reconstructed.

Lossless Compression

A compression method where no original detail is lost, allowing the original uncompressed file to be perfectly reconstructed.

MPEG-3 (MP3)

A lossy compression technology that reduces music file sizes by about $90\%$ by removing sounds outside human hearing range and using perceptual music shaping.

JPEG

A lossy compression algorithm used for bitmap images that eliminates colour shades the human eye cannot easily notice.

Run-Length Encoding (RLE)

A lossless compression method that encodes strings of adjacent, identical data into two values: the count of identical items and the data item itself.