# Computer science glossary 1 up to 389(priorities)

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- Created by: George Heard
- Created on: 29-03-19 09:37

Vectored interrupt mechanism

A method of handling interrupts be pointing to the first memory address of the instructions needed

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Two's complement

A method of working with signed binary values

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Unsigned binary

Binary that represents positive numbers only

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Vector graphics

A graphic consisting of components defined by geometric formulae and associated properties, such as line colour and style

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Picture element (pixel)

The smallest identifiable component of a bitmap image, defined by just two properties: its position in the bitmap matrix and its colour

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Kibi

A prefix representing the fact 2X10 (1024) written as the symbol Ki

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Mebi

a prefix representing the fact 2X20 (1048576) written as the symbol Mi

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Gibi

A prefix representing the fact 2X30 written as the symbol Gi

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Lossless compression

Coding techniques that allow subsequent decoding to recreate exactly the original file

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Lossy compression

Coding techniques that cause some information to be lost so that the exact original file cannot be recovered in subsequent decoding

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Router

A device that acts as a node on the internet

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Gateway

A device that connects networks of different underlying technologies

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Server

A device that provides services via a network

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IPv4 address

A 32-bit long, hierarchical address of a device on the internet

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Domain name system (DNS)

A hierarchical distributed database installed on domain name servers that is responsible for mapping a domain name to an IP address

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Random-access memory (RAM)

Volatile memory that can be read from or written to any number of times

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Read-Only memory (ROM)

Non-volatile memory that cannot be written to but can be read from any number of times

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Memory address

A specific location in memory where instructions or date are stored

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Assignment

The process of giving a value to a variable or constant

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Constant

An item of data whose value does not change

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Variable

An item of data whose value could change while the program is being run

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Debug

The process of finding and correcting errors in programs

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Declaration

The process of defining variable and constants in terms of their name and data type

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Data type

Determines what sort of data are being stored and how it will be handled by the program

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Integer

Any whole positive or negative number including zero

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pointer

A data item that identifies a particular element in a data structure - normally the front or rear

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Array

A set of related data items stored under a single identifier. Can work on one or more dimensions

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Element

A single value within a set or list - also called a member

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Record

One line of a text file

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Syntax

The rules of how words are used within a given language

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Selection

The principles of choosing what action to take based on certain criteria

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Nesting

Placing one set of instructions within another set of instructions

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Iteration

The principles of repeating processes

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Definite Iteration

A process that repeats a set number of times

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Indefinite iteration

A process that repeats until a certain condition is met

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Loop

A repeated process

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Sequence

The principle of putting the correct instructions in the right order within a program

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Arithmetic operation

Common expressions such as +,-,/,*

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Rounding

Reducing the number of digits used to represent a number while maintaining a value that is approximately equivalent

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Truncating

The process of cutting off a number after a certain number of characters or decimal places

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Random number generation

A function that produces a completely random number

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Pseudo-Random number generator

Common in programming languages, a function that produces a random number that is not 100% random

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Relational operations

Expressions that compare two values such as equal to or greater than

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Boolean operations

Expressions that result in a TRUE or FALSE value

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AND + pic

Boolean operation that outputs true if both inputs are true

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OR + pic

Boolean operations that outputs true if either of its inputs are true

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NOT + pic

Boolean operations that inverts the result so true becomes false and false becomes true

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XOR + pic

Boolean operation that is true if either input is true but not if both inputs are true

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String handling functions

Actions that can be carried out on sequences of characters

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Character code

A binary representation of a particular letter, number or special character

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Subroutine

A named block of code designed to carry out a specific task

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Procedure

Another term for a subroutine

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Subprogram

Another term for a subroutine

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Routine

Another term for a subroutine

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Local variable

A variable that is available only in specified subroutines and functions

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Global variable

A variable that is a available anywhere in the program

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Function

A subroutine that returns a value

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Functional programming

A programming paradigm that uses functions to create programs

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Parameter

Data being passed into a subroutine

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Argument

An item of data being passed to a subroutine

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Block interface

Code that describes the data being passed from one subroutine to another

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Exception handling

The process of dealing with events that cause the current subroutine to stop

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Procedural programming languages

Languages where the programmer specifies the steps that must be carried out in order to achieve a result

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Imperative programming languages

Languages based on giving the computer commands or procedures to follow

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Hierarchy chart

A diagram that shows the design of a system from the top down

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Structure chart

Similar to a hierarchy chart with the addition of showing how data are passed around the system

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Top-Down approach

When designing systems it means that you start at the top of the process and work your way down into smaller and smaller sub-processes

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flowchart

a digram using standard symbols that describes a process or system

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System flowchart

A diagram using standard symbols that desribes a process or system

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Pseudo-code

A method of writing code that does not require knowledge of a particular programming language

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Naming conventions

The process of giving meaningful names to subroutines, functions, variables and other user-defined features in a program

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Dry run

The process of stepping through each line of code to see what will happen before the program is run

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Trace table

A method of recording the result of each step that takes place when dry running code

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Modular design

A method of system design that breaks a whole system down into smaller units, or modules

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Exncapsulation

The concept of putting properties, methods and data in one object

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method

The code or routings contained within a class

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Properties

The defining features of an object or class in terms of its data

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Class

defines the properties and methods of a group of similar objects

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Object

A specific instance of a class

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Inheritance

The concept that properties and methods in one class can be shared with a subclass

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class diagrams

A way of representing the relationship between classes

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Instantiation

The process of creating an object from a class

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Polymorphism

The ability of different types of data to be manipulated with the same method

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Overriding

Where a method described in the subclass takes precedence over a method with the same name in the base class

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Composition aggregation

Creating an object that contains other objects, and will cease to exist if the containing object is destroyed

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Association aggregation

Creating an object, that contains other objects, which can continue to exist even if the containing object is destroyed

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data structure

A common format for storing large volumes of related data, which is an implementation of an abstract data type

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Abstract data type

A conceptual model of how data can be stored and the operations that can be carried out on the data

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File

A collection of related data

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Array

A set of related data items stored under a string identifier. Can work on one or more dimensions

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Text file

A file that contains human- readable characters

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Binary file

Stores data as sequences of 0s and 1s

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Record

One line of a text file

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Field

An item of data

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Queue

A data structure where the first item added is the first removed

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Stack

A data structure where the last item added is the first item removed

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Static data structure

A method of storing data where the amount of data stored (and memory used to store it) will vary as the program is being run

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dynamic data structure

A method of storing data where the amount of data stored(and memory used to store it) will vary as the program is being run

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Heap

A pool of unused memory that can be allocated to a dynamic data structure

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Stack frame

A collection of data about a subroutine cell

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Call stack

A special type of stack used to store information about active subroutines and functions within a program

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Interrupt

A signal sent to a device or program to the processor requesting its attention

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Nesting

The process of putting one statement inside another statement

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Recursion

The process of a subroutinge calling itself

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Queue

A FIFO structure where data leaves in the order it arrives

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FIFO

first in first out refers to a data structure such as a queue where the first item of data entered is the fist item of data to leave

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Linear queue

A FIFO strucutre implemented as a ring where the front and read pointers can wrap aroudn from the end to the start of the array

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Priority queue

A variation of a FIFO structure where some data may leave out of sequence where it has a higher priority than other data items

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Circular queue

A FIFO data structrure implemented as a ring where the front and read pointers can wrap around from the end to the start of the array

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Graph theory

The underlying mathematical principles behind the use of graphs

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Arc

A join or relationship between two nodes - also known as an edge

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Vertex/vertices

An object in a graph - also known as a node

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Weighted graph

A graph that has a data value labelled on each edge

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Undirected graph

A graph where the relationship between vertices is two-way

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Directed graph

A graph where the relationship between vertices is one-way

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Latency

The time delay that occurs when transmitting data between devices

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Adjacency list

A data structure that stores a list of nodes with their adjacent nodes

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Tree

A data structure similar to a graph, with no loops

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Node

An object in a graph-also known as a vertex

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Edge

A join of relationship between nodes also known as an arc

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Root

The starting node in a rooted tree structure from which all other nodes branch off

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Parent

A type of node in a tree, where there are further nodes below it

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Child

A node in a tree that has nodes above it in the hierarchy

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Leaf

A node that does not have any other nodes beneath it

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Binary tree

A tree where each node can only have up to two child nodes attatched to it

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Hash table

A data structure that stores key/value pairs based on an index calculated from an algorithim

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Key/value pair

The key and its associated data

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Hashing algorithim

Code that created a unique index from given items of key data

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Cache

A high- speed temporary area of memory

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Collision

When a hasing algorithim produces the same index for two or more different keys

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Clustering

When a hashing algorithim produces indices that are not randomly distributed

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Load factor

The ratio of how many indices are available to how many there are in total

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index

The location where values will be stored, calculated from the key

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Chaining

A technique for generating a unique index when there is a collision by adding the key/value to a list stored at the same index

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Rehashing

The process of running the hashing algorithm again when a collision occurs

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Dictionary (data structure)

A data structure that maps key data

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Associative array

A two-dimensional structure containing key/value pairs of data

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Magnitude

One of the two components of a vectore - refers to its size

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Direction

One of the two components of a vector

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Components

Teh values within a vector

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Scalar

A real value used to multiplu a vector to scale the vectore

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Dot product

Multiplying two vectors toether to produce a number

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Convex combination

A method of multiplying vectors that produces a resulting vector within the convex hull

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Vector space

A collection of elements that can be formed by adding or multiplying vectors together

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Convex hull

A spatial representation of the vector space between two vectors

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Implementation

Creating code to produce a programmed solution

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Array

A set of data items of the same type grouped together with the same identifier

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Edge

A connection between two nodes in a graph or tree structure

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Graph

A data type made up of nodes and edges

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Breadth first

A method for traversing a graph that explores nodes closest to the starting node first before progressively exploring nodes that are further away

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Depth first

A method for traversing a graph that starts at a chosen node and explores as far as possible along each branch away from the starting node before backtracking

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Queue

A data structure where the first item added is the first item removed

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Node

Elements of a graph or tree

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Binary tree

A structure where each node can only have up to two nodes attached to it

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Pre-order

A method of traversing a tree by visiting the root, traversing the left subtree and traversing the right subtree

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In-order

A method of traversing a tree by traversing the left subtree, visiting the root and traversing the right subtree

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Post-order

A method of traversing a tree by traversing the left subtree, traversing the right subtree and then visiting the root

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Traversal

The process of reading data from a tree or graph by visiting all of the nodes

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Binary search

A technique for searching data that works by splitting datasets in held repeatedly until the search data is found

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Recursion

A technique where a function can call itself in order to complete a task

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Single source

In Dijkstra's algorithm it means that the shortest path is calculated

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Shortest path

The shortest distance between two vertices based on the weighting of the edges

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Linear search

A simple search technique that looks through data one item at a time until the search term is found

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Binary search

A technique for searching data that works by splitting datasets in half repeatedly until the search data is found

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Binary tree search

A technique for searching a binary tree that traverses the tree until the search term is found

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Reverse polish Notation (RPN)

Another term for postfix notation (a mathematical notation in which operators follow their operands)

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Infix

Expressions that are written with the operators within the operands e.g. 2+3

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Operator

The mathematical process within an expression

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SODMAS

A methodology for evaluation mathematical expressions in a particular sequence

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Polish notation

Another way of describing prefix notation(where operators precede their operands

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Interpreter

Software that translates and executes programs line by line by converting programming statements either into machine code or by calling instructions to carry out the high-level language statements

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Operand

A value within an expression

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Prefix

Expressions that are written with the operators before the operands e.g. + 2 3

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Postfix

Expressions that are written with the operators after the operands e.g. 2 3 +

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In-order traversal

A method of extracting data from a binary tree that will result in an infix expression

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Post-order traversal

A method of extracting data from a binary tree that will result in postifx expressions

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Pre-order traversal

A method of extracting data from a binary tree that will result in prefix expressions

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Vector graphics

An image made up of objects and coordinates

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Bubble sort

A technique for putting data in order by repeatedly stepping through an array, comparing adjacent elements and swapping them if necessary until the array is in order

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Iteration

repeating the same process several times in order to achieve a result

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Merge sort

A technique for putting data in order by splitting lists into single elements and then merging them back together again

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Logical reasoning

The process of using a given set of facts to determine whether new facts are true or false

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Algorithm

A sequence of instructions

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Representational abstractions

The process of removing unnecessary details so that only information that is required to solve the problem that remains

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Abstraction by generalisation categorisation

The concept of reducing problems by putting similar aspects of a problem into hierarchical categories

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Top-down design

related to the modular approach, this starts with the main system at the top and breaks it down into smaller and smaller units a bit like a family tree

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Functional abstraction

Breaking down a complex problem into a series of reusable functions

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Data abstractions

Hiding how data is represented so that it is easier to build a new kind of data object e.g. building a stack from an array

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Problem abstraction

removing unnecessary details in a program until the underlying problem is identified to see if this is the same as a problem that has been already solved

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Information hiding

The process of hiding all details of an object that do not contribute to its essentials characteristics

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Decomposition

Breaking down a large task into a series of subtasks

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Composition aggregations

Building up a while system from smaller units. The opposite of decomposition

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Finite

Countable

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Finite state machine (FSM)

any device that stores its current status and whose status can change as the result of an input. Mainly used a conceptual model for designing and describing systems

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State transition diagram

A visual representation of an FSM using circles and arrows

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Accepting state

The state that identifies whether an input has been accepted

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State Transition table

A tabular representation of an FSM showing inputs, current state and the next state

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Mealy machine

A type of finite state machine with outputsq

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Cipher

An algorithm that encrypts and decrypts data, also known as code

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Shift Cipher

A simple substation cipher where the letters are coded by moving a certain amount forward or backwards in the alphabetq

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Turing machine

A theoretical model of computation

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Read/write head

The theoretical device that writes or reads from the current call of a tape in a turing machine

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Halting state

Stops the turing machine

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Start state

The initial state of a turing machine

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Transition function / rule

A method of notating how a turing machine moves from one state to another and how the data on the tape changes

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State transition diagram

A visual representation of the transition function of a turing machine

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Instruction table

A method of describing a turing machine in tabular form

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Universal machine

A machine that can simulate a turing machine by reading a description of the machine along with the input of its own tape

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Regular language

Any language that can be described using regular expressions

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Regular expression

Notation that contains strings of characters that can be matched to the contents of a set

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Context - feee language

An unambiguous way of describing the syntax of a language useful where the language is complex

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Backus-Naur Form (BNF)

A form of notation for describing the syntax used by a programming language

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Set

A collection of symbols in any order that do not repeat

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Terminal

In BNF, it is the final element that requires no further rules

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Syntax diagram

A method of visualising rules written in BNF or any other context - free language

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Natural number

A positive whole number including zero

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Set building

The process of creating sets by describing them using notation rather than listing the elements

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Member

Describes a value or element that belongs to a set

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Empty set

The set that contains no values

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Finite set

A set where the elements can be counted using natural number up to a particular number

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Infinite set

A set that is not finite

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Cardinality

The umber of elements in a set

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Countable set

A finite set where the elements can be counted using natural numbers

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Countably infinite sets

Where the elements can be put into a one-to-two correspondence with the set of natural numbers sets

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Cartesian product

Combining the elements of two or more sets to create a set of ordered pairs

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Union

Where two sets are joined and all of the elements of both sets are included in the joined set

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Intersection

Describes which elements are common to both sets when two sets are joined

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Difference

Describes which elements differ when two sets are joined together

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Subset

A set where the elements of one are entirely contained within the other; can include two sets that are exactly the same

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Proper subset

Where one set is wholly contained within another and the other set has addition elements

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Function

relates each element of a set with the element of another set

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Domain

All the values that may be input to a mathematical function

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Codomain

All the values that may be input to a mathematical function

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Factorial

The product of all positive integers less than or equal to n e.g. 3! is 3*2*1

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Space complexity

The concept of how much space an algorithm requires

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input size

In big o notation the size of whatever you asking to work with e.g. data, parameters

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Time complexity

The concept of how much time an algorithm requires

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constant time

In big 0 notation where the time taken to run an algorithm does not vary the input size

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Linear time

In big 0 notation where the time taken to run and algorithm increases in direct proportion with the input size

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Exponential time

In big 0 notation where the time taken to run an algorithm increases as an exponential function of the number of inputs. E.g. for each additional input the time taken might double

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Logarithmic time

In big 0 notation where the time taken to run and algorithm increased or decreased in line with a logarithm

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Polynomial time

In big 0 notation where the time taken to run the algorithm is a polynomial function of the input size

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Tractable problem

A problem that can be solved in an acceptable amount of time

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Intractable problem

A problem that cannot be solved within an acceptable time frame

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Heuristic

With algorithms it is a method for producing a 'rule of thumb' to produce an acceptable solution to intractable problems

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Unsolvable problem

A problem that it has been proved cannot be solved on a computer

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Halting problem

An example of an unsolvable problem where it is impossible to write aprogram that can work out whether another problem will halt given a particular input

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Natural number

A positive whole number including zero

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rational number

Any number that can be expressed as a fraction or ratio of integers

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Irrational number

A number that cannot be represented as a fraction or ratio as the deciaml form will contain infinite repeating values

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Real number

Any positive or negative number with or without a fractional part

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Ordinal number

A number used to identify position relative to other numbers

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Cardinal numbers

A number that identifies the size of something

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Well-ordered set

A group of related numbers with a defined order

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Array

A data structure where data items are grouped together under a single identifier and are then accessed based on their position

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Number base

The number of digits available within a particular number system e.g. base 10 for a decimal base 2 for binary

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Bit

A single binary digit from a binary number- either a zero or a one

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Unit

The grouping together of bits or bytes to form larger . blocks of measurement e.g. MB, GB

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Unsigned binary

Binary that represents positive number only

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Fixed point

Where the decimal/binary point is fixed within a number

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Floating point

Where the decimal/binary point can move within a number

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signed binary

Binary with a positive or negative sign

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overflow

When a number is too large to be represented with the number of bits allocated

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Underflow

When a number is too small to be represented with the number of bits allocated

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Normalisation

A process for adjusting numbers onto a common scale

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Precision

How accurate a number is

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Mantissa

The significant digits that make up a number

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Exponential time

The "power of" part of a number indicating how far a binary point should be shifted left or right

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Character code

A binary representation of a particular letter, number or special character

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ASCII

A standard binary coding system for characters and numbers

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Unicode

A standard binary coding system that has superseded ASC!!

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Parity bit

A method of checking binary codes by counting the number of 0s and 1s in the code

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Majority voting

A method of checking for errors by producing the same data several times and checking it is the same each time

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Check digit

A digit added to the end of binary data to check the data is accurate

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Bit-mapped graphic

An image made up of individual pixels

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Pixel

An individual picture element

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Resolution

Width x height or pixels per inch

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Colour depth

The number of bits or bytes allocated to represent the colour of a pixel in a bit-mapped graphic

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Vector graphic

An image made up of objects and coordinates

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Compresssion

The process of reducing the number of bits required to represent data

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Run-length coding

A method of compressing by eliminating repeated data

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Dictionary-based encoding

a method of compressing text files

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Encryption

the process of turning plaintext into scrambled ciphertext, which can only be understood if it is decrypted

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Decryption

The process of deciphering encrypted data or mesages

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Plaintext

Data in human-readable form

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Cipher text

encrypted data

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Caesar cipher

A substitution cipher where one character of plaintext is substituted for another which becomes the ciphertext

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Vernam cipher

A method of encryption that uses a one-time pad(key) to create cipher text that is mathematically impossible to decrypt without the key

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Transposition cipher

A method of encryption where the characters are rearranged to form an anagram

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Key

In cryptography it is the data that is used to encrypt and decrypt the data

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Substitution cipher

A method of encryption where one character is substituted for another to create cipher text

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Polyalphabetic

Using more than one alphabet

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Frequency analysis

In cryptography it is the study of how often different letters or phrases are used

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Railfence cipher

A type of transposition cipher that encodes the message by splitting it over rows

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Route cipher

A type of transposition cipher that encodes the message by placing it into a grid

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One-time pad

A key that is only used once to encrypt and decrypt a message and is then discarded

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Baudot code

A five-digit character code that predates ASCII and unicode

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Computational security

A concept of how secure data encryption is

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Computational hardness

The degree of difficulty in cracking a cipher

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Hardware

A generic term for the physical parts of the computer ,both internal and external

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Software

A generic term for any program that can be run on a program

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Application software

Programs that perform specific tasks that would need doing even if computers didn't exist e.g. editing text, carrying our calculations

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Utility programs

Programs that perform specific common task related to running the computer e.g. zipping files

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Library programs

Code, data and resources that can be called by other programs

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Translators

Software that converts programming language instructions into 0s and 1s (machine code) There are three types - compilers, assemblers

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Compiler

A program that translates a high-level language into machine code by translating all of the code

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Assembler

A program that translates a program written in assembly language into machine code

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Interpreter

A program for translating a high-level language by reading each statement in the source code and immediately performing the action

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Operating system software

A suite of programs designed to control the operations of the computer

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Virtual machine

The concept that all of the complexities of using a computer are hidden from the user and other software by the operating system

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Resource management

How an operating system manages hardware and software to optimise the performance of the computer

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Processor

A device that carries out computation on data by following instructions, in order to produce an output

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Scheduling

A technique to ensure that different users or different programs are able to work on the same computer system at the same time

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Memory management

How the operating system uses RAM to optimise the performance of the omputer

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File management

How an operating system stores and retrieves files

315 of 389

Machine code

The lowest level of code mad up of 0s and 1s

316 of 389

Assembly language

A way of programming that involves writing mnemonics

317 of 389

Mnemonics

Short codes that are used as instructions when programming e.g. LDR , ADD

318 of 389

Source code

Programming code that has not been compiled into an executable file

319 of 389

Assembler

A program that translates a program written in assembly language into machine code

320 of 389

Object code

Compiled code that can be run as an executable on any computer

321 of 389

Low-level language

Machine code and assembly language

322 of 389

High-level language

A programming language that allows programs to be written using english key words and that is platform independant

323 of 389

Imperative language

A language based on giving the computer command or procedures to follow

324 of 389

Object-oriented language

A programming paradigm that encapsulates instructions and data together into objects

325 of 389

Declarative languages

Languages that declare of specify what properties a result should have e.g. results will be based on functions

326 of 389

Functional language

A programming paradigm that uses mathematical functions

327 of 389

Translator

The general name for any program that translates code from one language to another e.e.g translating source code into machine code

328 of 389

Interpreter

A program for translating a high-level language by reading each statement in the source code and immediately performing the action

329 of 389

Compiler

A program that translates a high-level language into machine code by translating all of the code

330 of 389

Bytecode

An instruction set used for programming that can be executed on any computer using a virtual machine

331 of 389

Truth table

A method of representing/ calculating the result of every possible combination or inputs in a boolean expression

332 of 389

AND gate

result is true if both inputs are true

333 of 389

OR

Boolean operation that outputs true if either of its inputs are true

334 of 389

NOT

Boolean operation that inverts the result so true becomes false and false becomes true

335 of 389

NAND

Boolean operation that outputs true if any of the inputs are false

336 of 389

NAND gate

Result is true if any of the inputs are false

337 of 389

NOR

Boolean operation that outputs true if all of its inputs are false

338 of 389

NOR gate

Result is true if both inputs are false

339 of 389

XOR

Boolean operation that is true if either input is true but not if both inputs are true

340 of 389

De Morgan's law

A process for simplifying boolean expressions

341 of 389

Logic gate

An electronic component used to perform boolean algorithms

342 of 389

Boolean expressions

An equation made up of boolean operations

343 of 389

AND gate

Result is true if both inputs are true

344 of 389

OR gate

Result is true if either input is true

345 of 389

Not gate

Inverts the result so true becomes false and false becomes true

346 of 389

NAND gate

Result is true if any of the inputs are false

347 of 389

XOR gate

Result is true if either input is true but not if both inputs are true

348 of 389

NOR gate

Result is true if both inputs are false

349 of 389

Logic circuit

A combination of logic gates

350 of 389

Arithmetic logic unit (ALU)

Part of the processor that processes and manipulates data

351 of 389

Half adder

A circuit that performs addition using inputs from A and B only

352 of 389

Full adder

A circuit that performs addition using inputs from A and B plus a carry bit

353 of 389

Carry bit

Used to store a 0 or 1 depending on the result of binary addition

354 of 389

Flip-Flop

A memory unit that can store one bit

355 of 389

Edge-triggered D-type Flip-flop

A memory unit that changes state with each pulse of the clock

356 of 389

Clock

A device that generates a signal used to synchronise the components of a computer

357 of 389

Processor

A device that carries out computation on data by following instructions, in order to produce an output

358 of 389

Main memory

stores data and instructions that will be used by the processor

359 of 389

Fetch-execute cycle

The continuous process carried out by the processor when running programs

360 of 389

Chip

An electronic component contained within a thin slice of silicon

361 of 389

Bus

Microscopic parallel wires that transmit data between internal components

362 of 389

Data bus

Transfers data between the processor and memory

363 of 389

Input/Output (I/O) controller

Controls the flow of information between the process and the input and output devices

364 of 389

word length

The number of bits that can be addressed, transferred or manipulated as one unit

365 of 389

Address bus

Used to specify a physical address in memory so that the data bus can access it

366 of 389

Addressable memory

The concept that data and instructions are stored in memory using discrete addresses

367 of 389

Control bus

Controls the flow of data between the processor and other parts of the computer

368 of 389

Von neumann architecture

A technique for building a processor where data and instructions are stored in the same memory and accessed via buses

369 of 389

Harvard architecture

A technique for building a processor that uses separate buses and memory for data and instructions

370 of 389

Stored program concept

The idea that instructions and data stored together in memory

371 of 389

Fetch-execute cycle

The continuous process carried out by the processor when running programs

372 of 389

Control unit

Part of the processor that manages the execution of instructions

373 of 389

Arithmetic logic unit (ALU)

part of the processor that processes and manipulates data

374 of 389

Clock

A device that generates a signal used to synchronise components of a computer

375 of 389

Register

A small section of temporary storage that is part of the processor. Stores data or control instruction during the fetch-decode-execute cycle

376 of 389

Status register

Keeps track of the various functions of the computer such as if the result of the last calculation was positive or negative

377 of 389

Interrupt register

Stores details of incoming interrupts

378 of 389

Current instruction register(SIR)

register that stores the instructions that the CPU is currently decoding/executing

379 of 389

Program counter(PC)

Register that stores the address of the next instruction

380 of 389

Stored program concept

The idea that instructions and data are stored together in menory

381 of 389

Status register

keeps track of the various functions of the computer such as if the result of the last calculation was positive or negative

382 of 389

Memory Buffer register (MBR)

register that holds data that is either written to or copied from the CPU

383 of 389

Memory data register (MDR)

another name for the MBR

384 of 389

Bus width

The number of bits that can e sent down a bus in one go

385 of 389

Word length

The number of bits that can be addressed, transferred or manipulated as one unit

386 of 389

Multi-core

A chip with more than one processor

387 of 389

interrupt service routine

Calls the routine required to handle an interrupt

388 of 389

Priorities

A method for assigning importance to interrupts in order to process them in the right order

389 of 389

## Other cards in this set

### Card 2

#### Front

Two's complement

#### Back

A method of working with signed binary values

### Card 3

#### Front

Unsigned binary

#### Back

### Card 4

#### Front

Vector graphics

#### Back

### Card 5

#### Front

Picture element (pixel)

#### Back

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