OCR GCSE Computer S - Paper 2 Keywords

alphanumeric

collective name for letters, digits, symbols

analogue signal

a continuous signal which can't be processed by a computer

argument

a value that a parameter of a subprogram actually takes

ALU

part of CPU that carries out arithmetic and Boolean operations

array

data structure where all data is stored and defined under one variable name

ASCII

A 7-bit character set consisting of 128 characters

assembler

a program that turns assembly language into machine code

assembly language

low-level langauge

authentication

a process for checking user identity

binary

a counting system using base-2 consisting of 0s and 1s

binary shift

moving the bits in a binary number left or right and filling gaps with 0s

BIOS

Basic Input Output System

bitmap image

a graphic made up of pixels

bit

a binary digit either 0 or 1

bit rate

number of bits used per second of sampled audio

breakpoint

a programming tool used to halt a program at a specific place

byte

8 bits

casting

a way of changing from one data type to another

character

a single alphanumeric symbol

code editor

part of an IDE where you write and edit your source code

colour depth

the number of bits used for each pixel in an image file

comment

a note added to source code to say what part of a program does

comparison operator

compares two values and outputs either true or false

compiled code

an executable file created by a compiler

compiler

a programming tool to translate source code into machine code

compression

process of making the size of a file smaller

computational thinking

tackling a problem through decompostion, abstraction and algorithmic thinking

concatenation

joining strings together

constant

named value which cannot be altered as program is running

debugging

identifying and fixing errors in a program

dedicated system

a computer system designed to carry out a specific task

denary

system using base-10

digital signal

the representation of an analogue signal using binary data

DO WHILE loop

type of iteration statement

erroneous data

test data that a program isn't designed to accept

error diagnostics

information about an error once it is detected

extended ASCII

an 8-bit character set consisting of 256 characters

extreme data

Test data on the boundary of what a program will accept

field

A column of a database used to store a category of data

file handling

reading from and writing to external files

file sharing

copying files between services of work

final testing

when the testing stage of the software developing cycle is only done once to check the software.

flat-file database

A database that only contains one table of data

flow diagram

a graphical way of showing an algorithm

FOR loop

A type of count-controlled iteration statement

functionality testing

A type of testing that assesses how well a program meets the requirements

function

A sub program that takes parameters and returns a value

Gigabyte

1000 megabytes

global variable

a variable available throughout the whole program

GPU

A circuit for handling the processing of graphics and images

GUI

Allows the user to interact with the computer in a visual and intuitive way

GUI builder

an IDE tool for giving a program a graphical user interface

hexadecimal

a counting system using base-16 consisting of 0-9 digits and letters a-f

high-level language

A programming language like C++ or Java

IF statement

type of selection statement

indentation

Spaces put at the beginning of a line of code to help show a programs structure

input sanitation

removing unwanted characters from an input

input validation

Checking that an input meets a certain criteria

integer

A numerical data type for whole numbers

interpreter

A translator that turns source code into machine code

iteration statement

A statement which make a program repeat a series of instructions

iterative testing

Repeated testing done during the development of a program

kilobyte

1024 bytes

linker

a program tool which can combine codes

local variable

a variable that is only defined and useable within certain parts of a program

logic circuit

An electronic circuit for performing logic operations on binary data

logic error

when a program does something that was not intended

logic gate

an electronic circuit component that performs a Boolean operation

loop

A set of instructions that repeat until a condition is met

lossless compression

Temporarily removing a file to decrease file size

lossy compression

permanently removing a file to decrease file size

machine code

the lowest level of programming language formed of 1's and 0's

maintainability

a characteristic of a defensive design that helps programmers modify their creation

megabyte

1024 kilobytes

metadata

extra data stored in a file which gives information about the file's properties

Bit

one binary number (1 or 0)

Nibble

4 bits

real (or float)

numbers that have a decimal part

Boolean

can only take one of two values, usually TRUE or FALSE

string

used to represent text, collection of characters

decomposition

breaking a complex problem down into smaller problems and solving each one individually

abstraction

picking out important bits of information from the problem

algorithmic thinking

a logical way of getting from the problem to the solution

decisions

diamond boxes - flow diagram

start/stop

box with rounded corners - flow diagram

inputs/outputs

parallelogram - flow diagram

processes (instructions, calculations, processes)

rectangle - flow diagram

sub routine (reference other flow diagrams)

box with another boxes - flow diagram

sequences

only one way from start to finish

selections

multiple ways to get from start to finish

iterations

loops that allows to repeat a task

exponentiation

raise a number to a power

DIV operator

returns whole number part of division

MOD operator

returns remainder part of division

\==

is equal to

=!

is not equal to

<

is less than

\>

is greater than

is less than or equal to

\>\=

is greater than or equal to