OCR GCSE Computer Science - Paper 1 Key terms

Performs operations on data e.g. Addition, subtraction

Coordinating activities of the CPU

Quick, small stores of data within the CPU

Holds memory address for data or a instruction about to be used by the CPU

Holds actual data or instruction

Stores results of calculations performed in the ALU

Holds memory address of the instruction for each cycle

The next instruction is retrieved by CPU from main memory

The instruction is broken down and decided so computer can understand

The CPU performs what the instructions told

A computer system built within a large device e.g. Camera, washer, car

Memory loses its data when power of

Memory retains its data when power is lost

Read/write - function is to load open programs and operating system data currently in use - volatile

Can only be read, can't be changed, stores essential programs to be run in order to boot the computer - non-volatile

Collection of wires that carry signals between various components of the computer system

Processes all of the data and instructions that make the system work - can be effected by clock speed, number of cores, cache size

How fast the computer does the FDE cycle - a clock speed of 3Ghz means that 3 billion FDE cycles run every second

Virtual memory needed when the RAM is full so a temporary section is made which acts like a part of RAM

Solid state storage, non-volatile, more reliable/durable but can only be overwritten a limited number of times

Handles graphics and image processing

CD, DVD, Blue-ray ADV: cheap,easy to transport DIS: slow, less storage than hard drives, stored data degrades over time, cannot be written over

Hard drives ADV: fast access, stores large amounts of data, low cost DIS: not very portable, easily be broken

USB, flash memory, SD ADV: fast, small, light, easily potable, quiet DIS: more expensive, storage capacity less, limited number erase/write cycles

Data is stored on multiple servers in a remote location ADV: secure, can be accessed anywhere, no need to buy hardware, backed up by host DIS: needs internet, download and upload can be affected by internet connection, potential security issues, unclear who owns data in the cloud, could be expensive

essential software that links the hardware and other software together and generally manages the computer system

Text commands where user has to type in command

uses icons and other visual indicators to navigate and issue commands

maintains a computer

reorganises data on the hard drive to put fragmented files back together and moves files to collect all the free space

Full Backup - a copy is taken from from every file on the system Incremental Backup - only files created or edited since last backup are copied

reduces file size so they take up less space on hard disk

scrambles data to stop others from accessing it

source code is made freely available and users can modify it ADV: free, ,made for greater good, can be adapted DIS: small, buggy, security holes, no warranties, no customer support

only the compiled code is released and the source code is kept a secret ADV: warranties, well-tested, reliable, cheaper DIS: expensive, software may not fit user needs

within the range of an individual person, eg connecting bluetooth headphones to a phone

a network that connects devices close to each other e.g. school, house

a network within a large geographical area e.g. internet

amount of data that can be transferred in a given time

hardware that allows a device to connect to a network

connects devices on a LAN - is intelligent and routes data where it needs to go

responsible for transmitting data between networks

a set of standards for connecting computers

client has connection to server, servers can backup and store centrally but can be expensive and difficult to maintain

no central server, each computer equal in responsibility, have to work as both server and a client.

All devices connected to central switch or server controlling the network ADV: better performance, rest of network not affected in one fails, simple to add more devices DIS: wire needed for all devices, expensive

Devices correctly directly or indirectly to all other devices. No need for central server. Data sent along fastest route. ADV: faster DIS: expensive

assigned to all devices, unique and cannot be changed, permanent, identifies the actual device. Used for communication on the same network

assigned either manually or automatic, the location of your device on the internet. Static IP addresses are permanent and used to connect printers in a LAN or websites on the Internet. Dynamic addresses are allocated by a server each time the device accesses a network

split data into packets to be sent across the network, each packet given a number order of data, each router reads packet header and decides which way to send it according to IP rules, packets then arrive and reassemble them in the right order.

sets of rules for how devices connect on the network. Responsible for splitting data into packets and reassembling them.

used to access websites and communicate with web servers

more secure - encryption

used to access, edit and move files between devices

used to retrieve emails from a server, holds until download - then deletes from server

used to retrieve emails, server holds until you actually delete it- only download a copy. Allows email to be synchronised across multiple devices.

used to send emails, used to transfer emails between servers

Group of protocols which ahve similar functions. Self-contained. Each layer serves the layer above. ADV: breaks network communication into manageable pieces. Self-contained so a layer can be changed without affecting other layers. Forces companies to create compatible hardware/software.

Allows software to communicate with network using protocols, eg browser communicates with WWW using http or https

controlling data flow - splitting data into packets and checks data sent/delivered correctly, uses TCP

Makes connections between networks, adds IP address headers to packets, using IP

passing data over physical network, eg Ethernet

translates websites' domain name into its IP address

network that is entirely software based, created by partitioning of some physical network

invented scenario to engage a targeted victim in a manner that increases the chance the victim will divulge information

used to gain personal information for purposes of identity theft, using fraudulent e-mail messages that appear to come from legitimate businesses.

used to obtain information such as personal identification numbers (PINs), passwords and other confidential data by looking over the victim's shoulder.

malicious software - computer programs designed to infiltrate and damage computers without the users consent.

program loaded onto a user's computer without the user's knowledge and performs malicious actions. It can self-replicate, inserting itself onto other programs or files, infecting them in the process.

program that replicates itself in order to spread to other computers. Often, it uses a computer network to spread itself, relying on security failures on the target computer to access it.

program which misleads users of its true intent.

aims to gather information about a person or organization without their knowledge

unwanted advertisements to the user of a computer

trail and error to gain information

hacker stop users from accessing a part of a network, flooding network with useless traffic making computer very slow

The unauthorized taking or interception of computer-based information. Data theft is the act of stealing computer-based information from an unknowing victim with the intent of compromising privacy or obtaining confidential information.

SQL is a programming language used to search and query databases. An injection adds SQL commands for example to a login to access a database

organisations employ specialists to simulate potential attacks on their network

designed to find and stop malware from damaging a network

data is scrambled so that it is meaningless to anyone who does not have the key to decrypt it

allows members of the public to access information held by a public organisation

Law to protect use of data by organisations. 8 principles. Replaced by GDPR. Data must be held securely, kept up to date and not transferred outside the EEA.

Law against computer misuse, covers unauthorised access to data, changing/editing data and spreading viruses

protect intellectual property - anything someone has created

Very fast memory, close to CPU. Stores regularly used data for quick access. Low capacity and very expensive.

A multi-core processor will have 2, 4 or 8 processors which can process data independently of the rest. The more cores, the more instructions can be processed, so the faster the data can be processed

Cost, speed, capacity, portability, reliability

Data transmitted as light. High speed but expensive. Do not suffer from interference and can transmit data over long distances

Data transmitted over copper wires. Subject to interference. Traditional phone networks use copper.

Radio waves transmit data. Easy to set up wireless network and generally cheaper. Limited range and subject to interference between channels and blocking by physical objects, eg walls.

A global network connecting millions of computers, making it possible to exchange information. Biggest WAN.

Uniform Resource Locator - addresses used to access web servers

What is considered right and wrong by society

What is considered right and wrong in the eyes of the law

How groups of people with particular beliefs are affected

Impact on the natural world

A person/group of people who are affected by the actions of a company/organisation

Social media, employee monitoring, cookies, sharing of data

Controlling what people can access on the Internet

Monitoring what people do on the Internet