igcse comp sci

1-dimensional array

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an array that has only one index.

2-dimensional array

an array that has two indices.

abnormal test data

data that a program should not accept.

abstraction

It is the process of reducing complexity to enable the creation of an efficient set of rules that can be programmed.

Accelerometer sensor

This type of sensor measures acceleration forces. These may be static forces, such as the continual force of gravity. They can also be dynamic forces, such as those created by movement and vibrations.

access levels

the amount of direct access a user is given to data and resources. This could be set to be only certain sections of a whole collection of data and resources.

accumulator (ACC)

a register that is built into the ALU that stores the result of any interim calculations.

acknowledgement

a message that is sent from one device to another to indicate whether data is received correctly.

Acoustic sensor

This type of sensors measures the level of sound in an environment.

active script

this is the script that is used to produce any of the interactive elements of a web page.

actuator

a mechanical part that causes another device or part to move.

address

a memory location in RAM.

address bar

the section of a web browser where you type the web page address.

address bus

wires used for the transmission of addresses between components in a computer.

adware

a software based cyber issue that automatically creates popup advertisements.

analogue

continuous data that can be any value within a range.

analogue data

a continuous stream of data that is processed by humans.

analysis

the first stage of the program development life cycle that involves investigating the problem.

AND operator

returns True when both inputs are True.

anti

malware

anti

virus

application software

software that allows the user to perform a useful task.

architecture

the design of a computer system, including the components it contains.

arithmetic logic unit (ALU)

the component in the CPU that performs all the mathematical and logical operations required when processing data and instructions.

arithmetic operator

a symbol that performs a mathematical function, e g. '+' adds two values together.

array

a data structure where you can store multiple data items, of the same data type, under one identifier.

artificial intelligence

a part of computer science that looks at creating machines that can think and perform tasks a person would usually perform.

ASCII

a code for representing English characters as numbers, with each letter assigned a number from 0 to 127

assembler

converts assembly language into machine code.

assembly language

code written in mnemonics that allows direct manipulation of the hardware. It must be converted into binary code to run.

assignment

a type of programming statement that stores data in a variable or constant.

asymmetric

a type of encryption that uses two different keys to encrypt and decrypt data.

auto

completion

auto

correction

automated

a device that is operated without human interaction.

automated system

a system that is designed to operate without the need for any human intervention.

automatic repeat request (ARQ)

a type of error detection method that uses acknowledgement and timeout to see if data has arrived correctly after transmission.

automation

the use of automated equipment in a process, e.g. a factory.

average

the mean of a set of values, the total divided by the quantity.

bandwidth

The maximum amount of data transmitted over an internet connection in a given amount of time.

binary

a base

biometric device

a device that allows a user to record and input a biometric password.

biometric password

a type of password that uses a person's biological data, such as their fingerprint.

bit

is the smallest unit of data in a computer. A bit has a single binary value, either 0 or 1.

block minimising

you can make sections of code e.g. procedures, minimised so there is less code to read through

blockchain

a method that is used to track all the transactions made with a cryptocurrency.

bookmark

a link that can be created to allow you to quickly find a web page again.

Boolean

a data type. True or False.

Boolean operator

a symbol that joins multiple logical comparisons, can be AND OR or NOT

bootstrap

the first commands loaded when a computer starts, it checks hardware and loads the firmware.

bot

the name given to a computer that has had malware downloaded onto it that will cause it to be used in a DDoS attack.

botnet

a network of bots that are created to carry out a DDoS attack.

boundary test data

data that is on the edge of being accepted, and data that is on the edge of not being accepted.

break points

the use sets these points and the code stops running on that line. This lets you check the values and output from the code to that point.

brute

force attack

bubble sort

a sorting algorithm that moves through the list repeatedly swapping values in pairs.

byte

a unit of computer information or data

cache

a type of storage that is built into the CPU, to store the most frequently used data and instructions.

cascading style sheet (CSS)

a scripting language that is used to create a presentation template for a web page. It includes what kind of font and colour text will appear on the web page.

CASE statement

a type of selection construct where there is a list of different values to compare a single value against.

casting

converting data from one data type to another data type.

cell

the intersection of the rows and columns of transistors in solid

central processing unit (CPU)

a component in a computer system that processes data and instructions.

certificate authority

the awarding organisation that checks if another organisation is real and secure before awarding them a digital certificate.

char

A single character, e.g. A', '1'.

character set

it contains all the characters that are in that chAiacter set and the binary value that is assigned to each character.

check digit

a type of error detection method that is used for data entry. A calculation is performed on the data entered to create a value. Check digit values are compared to see if the data entered is correct.

checksum

a type of error detection method that performs a calculation on the data to create a checksum value. Checksum values arc compared after transmission to see if they match.

cipher text

the name given to data after transmission.

clock speed

the number of fetch

cloud storage

data storage that is owned by a third party and accessed by the user, using the internet.

coding

the writing of a program using one or more programming languages.

colour depth

the number of bits that arc used to create each colour in an image

command line interface (CLI)

a type of operating system where the user types commands.

comment

text within a program to describe its function, it is not executed when the program is run.

compare

identify / comment on similarities and / or differences.

compiler

a translator that converts a high

compression

a method that uses an algorithm to reduce the size of a file.

concatenation

joining two or more strings together.

constant

a named memory location that can store data. The data cannot change whilst a program is running.

control bus

wires used for the transmission of control signals between components in a computer.

control gate

a component that controls the flow of electric current

control unit (CU)

the component in the CPU that controls all the operations in the CPU.

cookie

small text file that is used to store personal data, by a web browser.

core

the part of the CPU that contains all the components that are used to perform the fetch

count

controlled loop

counting

statements in a program that record how many of something there are; a type of program, it adds one for every item to find out how many there are.

cryptocurrency

a type of digital currency that uses encryption procedures.

current instruction register (CIR)

a register that is built into the CU that holds the current instruction that is being processed in the CPU.

data backup

a copy of data that is stored separate from the computer.

data bus

wires used for the transmission of data and instructions between components in a computer.

data interception

intercepting, by technical means, non

data packet

a unit of data that is used to transmit data across a network.

data type

the characteristics of a piece of data. Common data types are string, integer, real and Boolean.

database

an example of application software to store and manipulate data.

decomposition

taking a system and splitting it into smaller sub

define

give precise meaning.

demonstrate

show how or give an example.

denary

a base

describe

state the points of a topic / give characteristics and main features.