A1.2 Computer Science Vocab

Binary Numbers

Language of modern computers, represents values using 0 and 1.

Transistors

Operate in binary, can turn electricity on and off.

Hexadecimal

base-16 number system that uses 16 distinct symbols to represent values. Decimal: base 10, 0-9

Binary: base 2, 0,1

Hex: base 16, 0-9, A-F, 0-f

ASCII encoding (American Standard Code for Information)

used to store characters and strings that are used as the standardized binary schemes enabling consistent storage.

Created to have a universal standard for interchange of text data. basic English letters, digits, control codes

Unicode

Created to solve the problem of various countries having multiple systems for languages.

Holds all the languages in the world

Includes languages, characters, emojis and mathematical and other technical symbols.

UTF-8

encodes 1-4 bytes per character, most commonly used encoding with ASCII.

UTF-16

2-4 bytes per character, 2 16-bit code units are used.

UTF-32

4 bytes per character, less common due to higher storage requirements.

Bitmap

reproduce images by using a grid of pixels, each pixel assigned a specific color and intensity.

Image resolution

Amount of detail an image holds, measured in pixels.

Calculation of an image

image size = width (pixels) height(pixels) color depth(bits per pixel)

Metadata

Information that is given about the file or data itself. "Data about data"

Analogue

information represented in a continuous form such as sound waves and not in discrete form like in digital.

Pixel

short for picture element, smallest unit of digital image, represents a single point in the image with a specific color and intensity.

Resolution

Increasing the number of pixels, higher resolution allows for greater detail and clarity and image with lower resolutions can lead to a loss of detail and a pixelated appearance.

Color depth

Increasing the number of colors, the number of bits used to represent the color of each pixel in a digital image. When color depth increased, a wide range of colors can be depicted.

Audio

Type of analogue form, continuous signal that represents sound waves through variations of air pressure.

Analogue to digital conversion (ADC)

converting an analogue signal into discrete signals.

Amplitude

magnitude of change in a sound wave, representing loudness or intensity of the sound.

Sampling

measuring analog signals at regular intervals to turn into digital form.

kHz (Kilohertz)

equal to 1000 cycles per second, commonly used to measure the sampling rate of audio signals.

Ways to store audio

WAV, AIFF, MP3, FLAC

Uncompressed formats

digital file types that store data, such as audio, video, or images, with no reduction in the original information.

Compressed formats

use algorithms to reduce the file size for storage or transmission.

Audio compression

reduce the file size by removing parts of the audio signal that are less noticeable to human senses.

WAV, AIFF, MP3, FLAC Compressed or uncompressed?

WAV~ Uncompressed

AIFF~ Uncompressed

MP3~Compressed

FLAC~ Compressed

Video

Made up of components that are all contained within an encapsulated container format such as MP4, MMKV, OR AVI. Stored as a sequence of still images, known as "frames".

Frames

Can be represented using a color model such as RGB. Stored same as images, each pixel having a value that can be represented using a color model.

Spatial compression

reduces file size by eliminating redundant information within each frame.

Temporal compression

Used for video that has consistent motion across frames, reduces file size by eliminating redundant information between consecutive frames, only capturing the changes or movements from one frame to the next.

Unsigned Binary

only represents positive integers using straightforward binary digits.

Signed binary

representing both positive and negative integers.

Two complements

Main way computers represent negative numbers in binary.

One's complement

Used to reperesent negative numbers in binary

Sign magnitude

Significant bit serves as the sign indicator with 0 representing positive numbers and 1 representing negative numbers.

Binary-coded decimal

exact decimal representation is crucial.

Gray code

only one bit changes between any two consecutive numbers

Excess-N

where a fixed bias (N) is added to the actual value to form an encoded value, you subtract this bias to decode it.

Fixed point representation

method used to store real numbers in binary by fixing the position of the binary point.

Floating point representation

describes how close a floating-point number can get to the exact real number it's trying to represent.

Basic gates

building various types of circuits within computers and other digital devices. Include AND, OR AND NOT gates.

Logic gates

made up of transistors, act as electronic switches, allowing or blocking the flow of electrical current.

AND gate

has two inputs and one output

OR gate

takes two inputs instead of one BUT will equal 1 more times.

Input = 0 and 1, output = 1

Input = 1, 0 , output=1

Input = 0,0 = output = 0

NOT gate

takes a single input and inverts it so the output is the opposite of whatever the input is.

Derived gates

Combinations of basic gates and provide more complex logic functions.

NAND gate (Not And)

constructed with an AND gate and followed by a NOT gate. Gives the opposite output to an AND gate.

NOR gate (NOT OR)

gives the opposite output to an OR gate as it is constructed using an OR gate followed by a NOT gate.

XOR gate

Outputs a 1 when exactly an input is a 1.

If input of A is one or input of b is 1, the output is 1.

If both inputs have the same value both 0s or 1s, then the output is 0.

XNOR Gate

Constructed using an XOR gate followed by a NOT gate. Outputs 1 instead of zero like XOR gate.

Karnaugh maps (K-maps)

tool that helps simplify Boolean expressions makes it easier to create simpler and more efficient digital circuits.

Two inputs

used for expressions with two variables.

Boolean Algebra

Math with true/false values using logical operations

Bits:

the smallest piece of data a computer can use, represented by a single 0 or 1

Bytes

group of 8 bits, represents one character (letter or number)

Stereo

method of sound reproduction that uses two or more audio channels to create the perception of sound coming from different directions.