computer science

Computer System

Utilizes hardware and software for input, processing, and output of data and instructions.

CPU Process

Involves fetching, decoding, and executing instructions from memory.

Hardware

Physical components of a computer like keyboard and mouse.

Software

Programs and applications running on a computer such as Safari and Microsoft Teams.

Input Device

Sends data and control signals to a computer, e.g., mouse, keyboard.

Output Device

Communicates processing results, e.g., monitor, printer.

Memory

Temporarily stores programs and data, e.g., RAM.

Storage Devices

Store data permanently, e.g., HDD, USB stick.

Binary Numbers

Used in computers due to electronic switches having two states, 0 or 1.

Binary-Denary Conversion

Process of converting 8-bit binary numbers to denary and vice versa.

Binary Addition

How to add together two 8-bit binary numbers. Rules: 0+1 = 1, 1+1 = 0 (carry 1), 1+1+1 = 1 (carry 1)

Units

Various units like bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte, petabyte.

Unit Calculations

Relationships between bits, nibbles, bytes, and larger units like KB, MB, GB.

Exterior Angles

Formula to calculate exterior angles of regular polygons.

Algorithm

Set of step-by-step instructions for a task or process.

Decomposition

Breaking down complex problems into smaller parts.

Flowchart

Visual representation of algorithms using symbols and arrows.

Sequence

Set of instructions to be followed in a specific order.

Selection

Choosing routes in a program, often using IF statements in Python.

Iteration

Repeating a process for efficiency, commonly done with FOR loops in Python.

Pseudocode

Structured way of writing algorithms.

Python Errors

Recognizing syntax errors in Python programs.

Variable

Location in RAM to store values during program execution.

Data Types

Variables have a data type. Common data types are:

·       String (text, numbers, spaces, symbols)

·       Integer (whole number)

·       Real (a number that can be a decimal)

·       Boolean (can only be one of two values, True or False)

Mathematical Operations

25.   The double asterisk means ‘to the power’ e.g. of 5 ** 2 (meaning 5 to the power of 2) = 25

DIV means integer division. It divides two values and rounds down the answer e.g. 5 // 2 = 2

MOD means modulo division. It gives the remainder of a division between two values e.g. 5 % 2 = 1.

Interpreting Algorithms

Understanding inputs, outputs, and variables in flowcharts or pseudocode.

Pixel

Smallest unit of color in an image.

Metadata

Information about data like resolution and author.

Image File Size

resolution*colour depth

colour depth

Colour depth is the set number of colours available for each pixel.

Resolution

Resolution is the density/number of pixels in an image. Resolution is calculated by multiplying the width*height of pixels in an image

units

Unit	Size
Bit	A binary digit, 1 or 0
Nibble	4 bits
Byte	8 bits
kilobyte (kB)	1024 bytes
megabyte (MB)	1024 kB
gigabyte (GB)	1024 MB
terabyte (TB)	1024 GB
petabyte (PB)	1024 TB