Computer Science Cheat Sheet

define Penetration Testing

testing the security of a system /network to find any vulnerabilities.

define Abstraction

is the process of removing unnecessary detail from a problem.

define Firewall

protect network from unauthorised access by controlling incoming /outgoing network connections.

define Volatile memory

temporary storage that is lost when power turns OFF (RAM)

define Interpreter

converts high level programming into machine code (line by line)

define Compiler

converts high level programming into machine code (whole program at once)

define Authentication

verifying the users identity when accessing data /network, to prevent unauthorised access.

variables constants

Scope:: which part of a program can see ________ /data structures.

define Pixel

single dot of colour in an image.

define RAM

Random access memory -> stores running applications while the computer is ON.

define Software

programs that are downloaded /installed onto a computer, the non physical parts of a computer system

define White Box Testing

White Box Testing stimulates the malicious insider (spy) who knows something about the target system.

define Cyber security

Cyber security are methods which prevent data /programs from Attack, Damage and Unauthorised access.

define Sample

Sample is a measure of amplitude at a point in time.

define Hardware

Hardware is the physical part of a computer, e.g hard drive

define Application software

application software are programs which help the user perform day to day tasks.

define Cloud storage

cloud storage secondary storage, at a remote location which is accessible via the internet.

define non-volatile memory

non-volatile memory is permanent storage that is kept when the power turns OFF (ROM, HDD)

Good Luck

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define Interpreter

The Interpreter converts high level programming into machine code (line by line)

define Compiler

the Compiler converts high level programming into machine code (whole program at once)

define Scope

Scope is part of a program can see variables/constants/data structures

define Bit

a bit is one unit of data, can only hold two values (0,1)

define Character set

A character set is a defined list of characters recognized by computers hardware and software

define Pixel

a pixel is a single dot of colour in an image

define Bitmap

Bitmap is a graphical image made up of pixels

define Pixel resolution

Pixel resolution is the number of pixels in an image

define Colour depth

colour depth is the bits used per pixel

define Sample

sample is the measure of amplitude at a point in time

define Sampling Rate

sampling rate is number of samples taken per second

define Sample resolution

sample resolution is the number of bits used per sample

define Computer system

computer system is the combination of hardware and software used to perform tasks

System software

programs which help run and maintain a computer system

define Application software

programs which help the user perform day to day tasks, stored on RAM while running

define Operating system

platform for hardware to use the software

define Volatile memory

temporary storage that is lost when power turns OFF (RAM)

define Non-volatile memory

permanent storage that is kept when the power turns OFF (ROM, HDD)

define Embedded System

computer system with a specific purpose, built into another system/machine

define RAM

stores running applications while the computer is ON

define Computer Network

a group of computers connected together to share resources

define Network Protocol

a set of rules which allow devices to communicate

define Network Security

methods which protect networks from unauthorised access and harm

define Authentication

verifying the users identity when accessing data/network, to prevent unauthorised access

define Firewall

protect network from unauthorised access by controlling incoming/outgoing network connections

define Encryption

scrambling data to change how it looks to prevent unauthorised access (only people with decryption key can access original)

define Cyber security

methods which prevent data/programs from Attack, Damage and Unauthorised access

define Penetration Testing

testing the security of a system/network to find any vulnerabilities

define Black-box testing

stimulate external hacking or cyber warfare attack

Low-Level Language examples

assembly code, machine code

define bubble sort

a simple sorting algorithm that repeatedly steps through the list to be sorted, compares each pair of adjacent items and swaps them if they are in the wrong order.

define ASCII

American Standard Code for Information Interchange, is a character encoding standard represent text in computers, telecommunications equipment, and other devices.

define unicode

an international encoding standard for use with different languages and scripts, by which each letter, digit, or symbol is assigned a unique numeric value that applies across different platforms and programs
ADVANTAGES: covers more languages, mathematical symbols for formulas etc

define lossless compression

Lossless compression allows the original data to be perfectly reconstructed from the compressed data

define lossy compression

in lossy compression, some data is removed and discarded, which reduces the overall amount of data and the size of the file