COMPUTER ( PAPER 1) Flashcards

Question

What is hacking?

Answer 1

* Hacking involves gaining unauthorized access to a system or network to steal or manipulate data, disrupt services, or cause damage. * The aim of hacking can vary from personal gain to activism or cyber espionage.

Answer 2

* A brute-force attack is a trial-and-error method used to crack passwords or encryption keys by trying every possible combination until the correct one is found. * The aim of a brute-force attack is to gain unauthorised access to a system or network OR to delete,change and steal data Or to disrupt business{place}. * It can be carried out manually or automatically by software.

Answer 3

- Data interception involves eavesdropping on communication channels to intercept and steal sensitive information, such as passwords, credit card numbers, or personal data. - The aim of data interception is to steal sensitive information for personal gain or to use it for further cyber-attacks.

Answer 4

* A DDoS attack is where multiple computers are used as bots. * They flood a server with lots of requests at same time which the server can’t respond to; causing it to crash/fail or become unavailable to users. * The aim of a DDoS attack is to disrupt the normal functioning of a system or network by denying users access to a website. * The aim can be for revenge, to affect someone's,Entertainment value OR To demand a ransom to stop it

Answer 5

* Malware is malicious software designed to harm or gain unauthorized access to a system or network. * It replicates itself and fills the hard disk.

Answer 6

A virus is a piece of code that attaches itself to a legitimate program or file and then replicates itself with an active host in order to spread to other programs or files on the computer. It can cause damage to the system, including deleting/corrupting data or damaging hardware. It also takes up memory space.

Answer 7

A worm is a standalone program means without an active host that can spread and replicate itself over computer networks. It can take up storage space or bandwidth. It can also cause damage to the system, including deleting/corrupting data or damaging hardware. - It also opens back doors to computers over the network and is used to deposit other malware on networked computers

Answer 8

A Trojan horse is a program that disguises itself as a legitimate program or file, but when installed, the malware it contains such as virus is installed that it can delete data or damage hardware.

Answer 9

Spyware is software that records all key presses and transmits these to a third party.

Answer 10

Ransomware is a type of malware that stops the user to access thier data by encrypting the user's files and demanding a ransom payment/fee to decrypt them. It can cause data loss, financial damage and disrupt business operations.

Answer 11

Adware is a type of software that displays unwanted advertisements on the computer without the user's consent. Some of these may contain spyware and some may link to viruses when clicked. It reduces internet speed which reduce device performance and redirects the user to fake websites.

Answer 12

* Phishing involves when a user is sent an email which contains a link to a fake/bogus website where the user is encouraged to enter their details. * The aim of phishing is to steal sensitive information for exmaple bank account info .

Answer 13

* Pharming involves malware being downloaded without the user’s knowledge. * This redirects the user to a fake website where they’re encouraged to enter their personal details. * The aim of pharming is to steal sensitive information for personal gain or to use it for further cyber attacks.

Answer 14

LOSS OF POWER --- USE A UPS LIQUIDS BEING SPILLED --- KEEP DRINKS AWAY FROM THE DEVICE NATURAL HAZARDS ~~ FLOOD FIRE HARDWARE/SOFTWARE FAULT HUMAN ERROR INCORRECT USE OF STORAGE DEVICE

Answer 15

**Impersonation**: This involves posing as someone else to gain trust or access to sensitive information. [co-worker, IT support personnel, or a law enforcement officer] **Baiting:** Enticing a victim with a desirable item or promise to extract sensitive information or gain access to a system **Pretexting:** involves creating a fake scenario to extract sensitive information. [The attacker might pose as a bank representative and ask for personal information to "verify your account.”]

Answer 16

* Social engineering involves manipulating individuals to gain access to confidential information or to perform an action that benefits the attacker. * The aim of social engineering is to exploit human behavior and vulnerabilities to gain unauthorized access to a system or network.

Answer 17

1. Access Levels 1. Authentication 1. Anti-malware 1. Firewall 1. Proxy server 1. SSL/TLS 1. Privacy Settings 1. URL 1. Communications 1. Automating Software Updates 1. Backup

Answer 18

* Anti-malware solutions are used to prevent and remove malware, which is a common type of security threat to data. * Anti-malware software includes anti-virus and anti-spyware programs, which help to detect and remove malicious software from a computer system. * This software works by scanning the computer’s files and any files being downloaded and comparing them to a list of known malwares. * If any malware is found, it is quarantined to prevent its spread. * The malware is then deleted. * Checks data before it is downloaded and stops the download if any virus is detected.

Answer 19

* Access levels are used to restrict access to sensitive information and provide users with different permission to access the data. * This helps to prevent unauthorised access, which is one of the main security threats to data. * Access levels are normally linked to a username and can be set based on a user's role, responsibility, or clearance level. * This limits the access to read,view,edit or delete the data to only those people who have the access. * This only allows the user to open files without editing or deleting them. This hides the file from the user. Full access Read-only access No access

Answer 20

* Passwords are used to protect sensitive data by preventing unauthorized access. * A strong password should be complex, unique, and not easily guessed. For example, @N$@r!128 * Passwords should be changed regularly, and users should avoid reusing passwords across multiple accounts which makes it more difficult to guess. * Users should be locked out after a set number of wrong attempts. * Password stop brute force attack.

Answer 21

Authentication is used to ensure that only authorized users can access data. TYPES OF AUTHENTICATIONS: - * PASSWORD * BIOMETRICS * TWO-FACTOR AUTHENTICATION

Answer 22

* Biometrics are statistical analyses of people's physical and Behavioral characteristics. * Authentication by identifying unique physical characteristics of a human such as fingerprints, facial recognition, or iris scans. * It locks out the user after set number of failed attempts.

Answer 23

**ADVANTAGES** * Physical and behavioral characteristics are harder to forge as they are unique to each individual. * It is very difficult to fake a biometric password. * A biometric password cannot be recorded by spyware. * Physical characteristics cannot be lost. * User Experience – Convenient and fast. **DISADVANTAGE** * Physical Disabilities- Injury or change in physical characteristics can be a barrier during authentication. * Once lost cannot be recovered. * They are expensive. * Environmental factors can prevent scanning-poor light, makeup, etc.

Answer 24

* It requires the users to provide two forms of authentication before accessing data, such as a password and a verification code sent to a mobile device. * This is pre-set by the user. * This provides an extra layer of security and reduces the risk of unauthorized access. * Data has to be entered into the same system, so if attempted from a remote location, it will not be accepted.

Answer 25

* A firewall can be software or hardware based. * It monitors incoming and outgoing traffic between the computer and the network and keeps a log of the traffic. * The firewall will compare the traffic with the criteria set by the user. * It will set the blacklist and whitelist and block any traffic that does not meet the criteria set.

Answer 26

* A proxy server can be software or hardware based. * Proxy servers are used to hide a user's IP address and location, making it more difficult for hackers to track them. * They act as a firewall and can also be used to filter web traffic by setting criteria for traffic. * Malicious content is blocked, and a warning message can be sent to the user. * Proxy servers are a useful security measure for protecting against external security threats as they can direct traffic away from the server.

Answer 27

**Similarities** * Check incoming and outgoing signals // filter traffic * Store whitelist/blacklist * Block incoming/outgoing signals and unauthorised access * Keep a log of traffic * Both can be hardware or software (or both) **Differences** * Proxy can hide user's IP address, firewall does not hide the user's IP address * Proxy intention is to divert attack from server, firewall is to stop unauthorised access * Proxy protects a server, firewall protects individual computer * Proxy processes client-side requests whereas firewall filters packets * Proxy transmits website data to the user, but a firewall does not (it allows valid signals) * Proxy allows faster access to a web page using cache, but a firewall does not (allow faster access or have cache) * Proxy can hide internal network from internet, but a firewall cannot

Answer 28

* Automating software updates ensures that software systems are up to date with the latest security patches, which helps to prevent security threats. * This is especially important for operating systems and software that are frequently targeted by hackers. * It does this by scanning the Internet for known updates to software that are installed on the computer. * If any updates are found, these can either be installed automatically or notify the user to install them.

Answer 29

Checking the spelling and tone of communications is important to prevent phishing attacks.

Answer 30

- Checking the URL attached to a link is another way to prevent phishing attacks. - Hackers often use fake URLs to trick users into visiting fraudulent websites. e.g., http://amaz.on.co.uk/ rather than http://amazon.co.uk/

Answer 31

* Privacy settings are used to control the amount of personal information that is shared online. * They are an important measure to prevent identity theft and other forms of online fraud. * Users should regularly review their privacy settings and adjust them as needed.

Answer 32

* Hacking - Passwords or Biometrics * Malware - * Viruses - Anti-virus software or Firewall * Worms - Anti-malware * Trojan horses - Anti-malware * Spyware - Anti-spyware or 2-step verification or Firewall * Ransomware - Anti-malware * Brute - force - attack - Password * Pharming - Checking URLs, Firewall,Proxy server * Phishing - Checking URLs or Checking the tone of communication. * Distributed Denial of services attack - Firewall or Email filters * Data interception - Using WEP for wardriving * Social engineering- Self awareness

Answer 33

A digital currency is a type of currency that exists only in electronic form and is not backed by any physical commodity or government. - Only Exists Electronically - Decentralised - Used for Transactions - Volatile Examples include Bitcoin, Ethereum, Litecoin, and Ripple

Answer 34

Blockchain is a digital ledger that records every transaction made with a particular digital currency Each transaction is time-stamped and added to the blockchain in a permanent and unalterable way Blockchain is a decentralised technology, meaning that it is not controlled by a single entity or authority Instead, every participant in the network has a copy of the ledger and can verify the transactions independently The blockchain is made up of "blocks" of transactions that are linked together in a "chain" using cryptographic algorithms This creates a secure and tamper-proof record of every transaction made with the digital currency Each transaction in the blockchain must be verified by multiple participants in the network This verification process ensures that the transaction is legitimate and prevents any fraudulent activity

Answer 35

An automated system is a combination of sensors,microprocessor and actuators that are designed and programmed to work automatically without any human help.

Answer 36

Sensors detect changes in the environment and convert them into electrical signals that can be processed by a microprocessor.

Answer 37

Acoustic Accelerometer Flow Gas Humidity Infra-red Level Light Magnetic field Moisture pH Pressure Proximity Temperature

Answer 38

**Acoustic** Sound levels To detect changes in sound levels of industrial machinery To monitor noise pollution In security system to detect suspicious sounds **Accelerometer** Acceleration rate, tilt, vibration Detecting sudden changes in vehicle movement and deploy safety features if needed In mobile phones to detect orientation of the device **Flow** Rate of gas, liquid or powder flow Detect changes in the flow through pipes in water system **Gas** Presence of a gas e.g. carbon monoxide Detect levels of gas in confined spaces Detect gas levels when fixing gas leaks **Humidity** Levels of water vapour Monitor humidity in greenhouses **Infra-red** Detecting motion or a heat source Security systems detecting intruders who break the beam Measures heat radiation of objects - used by emergency services to detect people **Level** Liquid levels Detects levels of petrol in a car tank Detect levels of water in a water tank Detect a drop in water levels due to a leak **Light** Light levels Automatically switching on lights when it gets dark (street lights, headlights) **Magnetic field** Presence and strength Anti-lock braking system Monitoring rotating machinery such as turbines **Moisture** Presence and levels of moisture Monitoring moisture in soil Monitoring damp in buildings **pH** Acidity or alkaline Monitoring soil to ensure optimum growing conditions Monitor pHlevels in chemical processes **Pressure** Gas, liquid or physical pressure Monitoring tyre pressure Monitoring pressure in pipes during manufacturing process **Proximity** Distance Monitoring position of objects in robotics Used in safety systems to prevent objects colliding **Temperature** Temperature in Celsius, Fahrenheit or Kelvin Used to maintain temperature in swimming pools Used to control temperature in chemical processes

Answer 39

Microprocessors analyse the signals from the sensors and make decisions based on pre-programmed logic.

Answer 40

Actuators receive signals from the microprocessor and perform actions such as opening a valve or turning on a motor.

Answer 41

* INDUSTRY * TRANSPORT * AGRICULTURE * WEATHER * GAMING * SCIENCES * LIGHTNING

Answer 42

**Manufacturing:** Automated systems are used in factories to assemble products, monitor quality control, and improve efficiency. **Inventory Management:** Automated systems help track and manage inventory levels, ensuring that materials are ordered and restocked as needed.

Answer 43

**Traffic Control:** Traffic lights and control systems automate traffic flow to reduce congestion and improve safety. **Automated Guided Vehicles (AGVs)**: These self-driving vehicles are used in warehouses and factories for material handling.

Answer 44

**Precision Farming**: Automated systems are used in agriculture to optimise planting, irrigation, and harvesting based on data collected from sensors and drones. **Livestock Monitoring:** Sensors track the health and location of livestock.

Answer 45

**Weather Forecasting:** Automated systems collect and analyse data from weather stations, satellites, and sensors to predict weather patterns and issue warnings.

Answer 46

**Game AI:**Automated systems create non-player characters (NPCs) with artificial intelligence, enhancing the realism and challenge in video games. **Procedural Content Generation:** Automated algorithms create game worlds, levels, and landscapes.

Answer 47

**Home Automation:** Automated lighting systems can adjust brightness and colour temperature based on user preferences or time of day. **Energy Efficiency:** Lighting systems can automatically turn off or dim lights when not in use to save energy.

Answer 48

**Laboratory Automation:** Automated systems are used in laboratories for tasks such as sample handling, data analysis, and high-throughput screening. **Observatory Control:** Telescopes and scientific instruments can be automated for remote observations.

Answer 49

Reduced labour costs Improved efficiency and accuracy Increased production rate - much faster than human operator Keeps humans away from hazardous conditions.

Answer 50

High initial investment Limited flexibility to changes in production processes Maintenance costs can be high Any computerised system can be subject to cyber attack.

Answer 51

Improved safety and reliability Reduced labour costs Improved fuel efficiency Improves the punctuality of public transports like trains.

Answer 52

High initial investment May not be suitable for all types of transportation Maintenance costs can be high Cyber attacks

Answer 53

Increased efficiency in planting and harvesting crops Improved crop yield and quality Reduced labour costs

Answer 54

High initial investment May not be suitable for all types of crops or terrain Maintenance costs can be high

Answer 55

Improved accuracy in weather prediction Ability to issue warnings in a timely manner Ability to collect large amounts of data quickly

Answer 56

May be affected by external factors like interference or equipment failure May not be 100% accurate all the time May require continuous monitoring and calibration

Answer 57

* Improved speed and efficiency in game development * Ability to create complex and interactive games * Reduced labour costs

Answer 58

* May not be suitable for all types of games or game development * May require significant programming expertise * May be affected by technical glitches or bugs

Answer 59

* Improved speed and accuracy in data collection and analysis * Ability to carry out complex experiments * Reduced labour costs

Answer 60

* High initial investment * May not be suitable for all types of experiments * May require significant technical expertise

Answer 61

* Improved energy efficiency * Ability to program lighting to suit different needs * Reduced labour costs

Answer 62

High initial investment May not be suitable for all types of lighting needs Maintenance costs can be high

Answer 63

Robotics is an area of computer science that deals with the creation, design, and operation of robots.

Answer 64

* Have a mechanical structure or framework * Have electrical components * Programmable

Answer 65

* A robot may not injure humans through action or inaction. * A robot must obey commands given by humans. * A robot must protect itself.

Answer 66

**INDUSTRY** Robots can be used in manufacturing and assembly lines to increase productivity and accuracy **Transport** Robots can be used in warehouses and logistics to move and transport goods **Agriculture** Robots can be used for tasks such as planting, harvesting, and spraying crops. **Medicine** Robots can be used in surgical procedures to increase precision and reduce risk of errors. **Domestic** Robots can be used for tasks such as vacuuming, lawn mowing, and cleaning. **Entertainment** Robots can be used as toys or in amusement parks to provide entertainment.

Answer 67

**Increased productivity:** robots can work continuously without breaks or fatigue SO other people dont need to do repetitive/mundane tasks. **Consistency and accuracy:** robots can perform tasks with a high level of precision and accuracy such as performing surgical procedures. **Safety:** robots can perform tasks that are dangerous or hazardous for humans **Cost-effective:** robots can help reduce labour costs in the long run Robots are prone to**cyber attack** and **malfunction**

Answer 68

AI is a branch of computer science dealing with the simulation of intelligent human behaviour by a machine , including: problem-solving, decision-making, natural language processing. The aim of AI is to create systems that will perform tasks that would normally require human intelligence.

Answer 69

AI is a collection of data and the rules that are stored to use that data. It also has the ability to reason and learn (uses machine learning) by adapting to its previous decision or mistakes so that it will not be made again. AI can also change its own rules or data to learn and adapt.

Answer 70

Are a form of AI that has been developed to mimic human knowledge and experience.

Answer 71

OIL AND MINERAL PROSPECTING DIAGNOSIS OF PATIENT’S ILLNESS TAX AND FINANCIAL CALCULATION STRATEGY GAMES LIKE CHESS

Answer 72

**knowledge base** - A database of facts to generate rules that are used to solve problems and make decisions. **rule base**- Stores a set of rules or logic that is used by the inference engine to apply the knowledge/link the facts in the knowledge base to solve specific problems and draw conclusions. **inference engine**- A program that applies the rules from the rule base to the facts in the knowledge base to solve problems. **Explanation system**- Informs the user of the reasoning behind its conclusion and recommendation. **User interface**- A way for users to interact with the system and provide input

Answer 73

They offer a high level of expertise. They offer high accuracy and the results are consistent. They have the ability to store vast amounts of ideas and facts.

Answer 74

* The set up and maintenance cost are very high. * They tend to give ‘cold’ responses which may not be appropriate in certain medical conditions. * Users of expert systems need considerable training to ensure that the system is being used correctly.

Answer 75

Machine learning is a subset of AI that focuses on giving computers the ability to learn and improve from data, without being explicitly programmed. The program has the ability to automatically adapt its own processes and/or data. Uses algorithms to analyse data and identify patterns or relationships. The system can learn from the data and improve its performance over time. Can be supervised or unsupervised: Supervised machine learning uses labelled data to train the system. Unsupervised machine learning uses unlabelled data.

Answer 76

**AI** Represents simulated intelligence in a machine. **Machine learning** This is the practice of getting machines to make decisions without being programmed to do so. **AI** The aim is to build machines that are capable of thinking like humans. **Machine learning** The aim is to make machines that learn through data acquisition.

Answer 77

CATEGORIZING SPAM EMAILS DETECTION OF FRAUDULENT ACTIVITY

Answer 78

Information on the internet is broken down into packets and are created by TCP and transmitted over the internet. Packets are small chunks of information/data.

Answer 79

Small chunks of data are easier and quicker to route over the internet than big chunks of data.

Answer 80

* packet header * payload * trailer

Answer 81

Source IP address Destination IP address Packet number

Answer 82

* Additional error checks * End of packet notification

Answer 83

Data is **broken down into small chunks of information** called packets. Each packet is given a **source address, a destination address and a packet number**. Each packet could take a **different route** which will be **set and controlled by the router** that will find the **shortest and fastest path** from the source to the destination address. The **packets may arrive out of order** but will be **reassembled to their original sequence according to the packet number** at the receiver's end. **Error checks** like parity check will be performed and if any error is found for example if a packet is missing or corrupted then a request is sent to send it again.

Answer 84

In this form of data transmission, there is a single wire over which data is sent one bit at a time making it inherently synchronised. Each bit is sent and received at a specific clock rate, ensuring that the sender and receiver remain synchronised and there is no need for the data to be reorder once it is received.

Answer 85

* It is less likely to have errors/interferences or the data being skewed. * Serial transmission is cheap over short and long distances as the cost of wire is fairly inexpensive * Transmission speed is adequate in certain situation ( or where it is usually used)

Answer 86

* Data transmission is slow, especially over long distances as only small quantities of data can be transmitted at a time * Serial transmission is expensive over very long distances as the cost of wire dramatically increases

Answer 87

In this form of data transmission, there are several wires of which multiple bits are transmitted simultaneously. Parallel data transmission is asynchronous as some bits may arrive quicker than others. This is known as skewing or skewed data.

Answer 88

* Parallel transmission is fast as large quantities of data can be transmitted at any one time * Can be downloaded and uploaded at the same time

Answer 89

* Parallel transmission is expensive over short distances as multiple wires need to be purchased. * Transmission is very expensive over long distances as the cost of wires dramatically increases with the distance. * It responds faster to request. * There can be issues of synchronisation - data can be skewed.

Answer 90

- SIMPLEX - FULL-DUPLEX - HALF-DUPLEX

Answer 91

Simplex transmissions are unidirectional and travel in only one direction **ADVANTAGE:** Simplex wires are cheap as only one wire is used **DISADVANTAGE:** Data transmission is slow as data still travels one bit at a time in only one direction at a time

Answer 92

Full-duplex transmissions are bidirectional but can transmit signals in both directions at the same time **ADVANTAGE:** Full-duplex transmission is faster as data can travel in both directions simultaneously. The receiver does not have to wait for the sender to stop before they can start transmitting their data **DISADVANTAGE:** Full-duplex is expensive as the wire technology to transmit in both directions is more difficult to implement

Answer 93

Half-duplex Half-duplex transmissions are bidirectional i.e. can travel in both directions, but not simultaneously **ADVANTAGE:** Half-duplex transmission is cheaper than simplex for bidirectional transmission as it requires fewer wires **DISADVANTAGE:** Transmission is still slow as data travels one bit at a time in only one direction at a time

Answer 94

* Connecting an external hard drive to a computer * Transmitting data over a telephone line

Answer 95

Transmitting data from a computer to a printer using a multi-wire connector

Answer 96

Transmitting data from a computer to a printer. The printer doesn’t need to send data back to the computer

Answer 97

Phone conversations where only one person needs to speak at a time A **walkie-talkie** is a two way radio with a push to speak button. The receiver is turned off while the transmitter is turned on. This prevents you from hearing the other person while you speak

Answer 98

Broadband connections to the internet. Data must be sent and received at the same time. Accessing information on the internet is known as downloading information. Putting information onto the internet for others to access is known as uploading Phone conversations where both people can talk and be heard at the same time allowing them to interrupt each other

Answer 99

The Universal Serial Bus (USB) is an asynchronous and serial method of transmitting data between devices and has become an industry standard. Many devices use USB such as keyboards, mice, video cameras, printers

Answer 100

* Automatically detects that the device has been connected * Automatically recognised and the appropriate device driver is loaded so that the device can communicate with the computer * If the device is new, the computer will look for a matching device driver. If one cannot be found then the user must download and install an appropriate driver manually

Answer 101

* Devices are automatically detected and drivers are automatically loaded for communication. This simplifies the data transmission process for the user * Cable connectors fit in only one way. This prevents incorrect connections and ensures compatible data transmission * As USB usage is standardised, there is a lot of support available online and from retailers * Several different data transmission rates are supported. * Newer USB standards are backwards compatible

Answer 102

* The maximum cable length is roughly 5 metres meaning it cannot be used over long distances, limiting its use * Older versions of USB have limited transmission rates for example USB 2.0 has 480Mbps * Very old USB standards may not be supported in the near future

Answer 103

An error is when data received is not as expected and therefore is difficult or impossible to process.

Answer 104

* Some errors are small and trivial such as a single swapped letter in a large text. * Other errors, in data such as postage addresses, aerospace coordinates or bank transfers, can be difficult to rectify or be disastrous. * Any job or task that relies on a computer to perform highly sensitive or secure processes must have methods of error checking and correction

Answer 105

Errors can occur using wired or wireless technology due to interference Examples of interference include wire degradation or electrical fields changing the signal Results of interference include: * Data loss - data is lost in transmission * Data gain - additional data is received * Data change - some bits have been changed or flipped

Answer 106

* Before data is transmitted a checksum value is calculated . * This value is calculated using a checksum algorithm for example if the sum of all the bytes in data is more than 200 then the checksum value is the product of all the bytes in the data. * This checksum value is appended to the data to be transmitted. * Once the data is transmitted the checksum value is recalculated using the same algorithm and compared with the transmitted checksum value. * If they are the same then there is no error otherwise an error has occurred

Answer 107

* The parity checking protocol determines whether bits in a transmission have been corrupted * Every byte transmitted has one bit as a parity bit which should be agreed by the sender and receiver. * The value of the parity bit can be even or odd which is determined by counting the number of 1’s in the byte, including the parity bit * If the number of 1’s does not match the agreed parity then an error has occurred * Parity checks only check that an error has occurred, they do not reveal where the error(s) occurred

Answer 108

* Echo checks involve transmitting the received data back to the sender. The sender then checks the data to see if any errors occurred during transmission * This method isn’t reliable as an error could have occurred when the sender transmits the data or when the receiver transmits the data. Neither will know when the error occurred. * If an error does occur the sender will retransmit the data

Answer 109

* A check digit will be calculated from the data using a mathematical algorithm. * This check digit is stored with the data. * When the data is entered, the check digit is calculated using the data and algorithm. * If the previously calculated check digit and the stored check digit match, * the data entered is correct otherwise the data entered is incorrect.

Answer 110

* ISBN * Barcode

Answer 111

* When the receiver receives transmitted data it must check for the presence of any errors. Errors can usually be detected but not always pinpointed * An Automatic Repeat Request is a protocol that notifies the sender that an error has occurred and that the data received is incorrect. It works as follows: * If an error is detected the receiver sends a negative acknowledgement transmission to indicate the data is corrupted * If no error is detected the receiver sends a positive acknowledgement transmission meaning the data is correct * If the receiver does not send any acknowledgement transmission then the sender waits for a certain time period known as a time-out before automatically resending the data * This process is repeated until all data has been received and acknowledged

Answer 112

Encryption involves encoding and scrambling data into a form that is meaningless using an algorithm and cannot be understood by anyone else other than the authorised party. Key is required to decrypt the data If data is stolen it will be meaningless.

Answer 113

In symmetric encryption both parties are given an identical secret key which can be used to encrypt or decrypt information meaning the decryption and the encryption algorithm are the same.

Answer 114

An asymmetric encryption also known as public key encryption, two keys are used: Public key: a key known to everyone Private key: a key known only to the receiver Both keys are needed to encrypt and decrypt information Asymmetric encryption works as follows: Person A uses a public key to encrypt their message Person A sends their message over the network or internet Person B decrypts the message using their secret private key Asymmetric encryption works such that only one private key can be used to decrypt the message and it is not sent over the internet like a symmetric key.

Answer 115

Systems software provides the services that the computer requires, including operating system and utility software.

Answer 116

This is a program designed to run other programs on a computer. It is considered the backbone of a computer, managing both software and hardware resources

Answer 117

* managing files * handling interrupts * providing an interface * managing peripherals and drivers * managing memory * managing multitasking * providing a platform for running applications * providing system security * managing user accounts

Answer 118

The file manager controls all of the different files on the system, e.g. text files, graphic files, and program files. It controls file permissions such as the user's ability to see or open a file, write a file or delete a file.It helps to organise and control files so that they are as easy to use as possible for the user. It can help to protect the user from accidental mistakes too.

Answer 119

Users must interact with the operating system through a user interface. The user interface is a system which converts what the user inputs to a form that the computer can understand and vice versa Many computer or database operating systems use complex programming languages which are not easy to use A user interface is created to allow easier control of the operating system by the system user. A good interface should be easy to use **e.g.**: consistent menu structures; consistent operations from actions like clicking the right mouse button

Answer 120

The overall intention of this is to handle all the devices that are connected to the computer system. This includes input devices such as a keyboard and mouse, it also includes output devices such as a monitor and printer It communicates with the devices through software called **drivers.** These translate the instructions by the device manager into one the devices can understand Peripherals like a mouse, keyboard and printer all need drivers so that they can communicate with the software

Answer 121

Memory management is in charge of the RAM. Programs use RAM throughout their operation. Some programs will be large and complex and use the RAM extensively whereas some are very small programs and won’t use it as much Memory management checks all requests from programs are valid and allocates accordingly. It will deallocate space and swap out data to virtual memory. It will ensure overall that different programs can be open at the same time

Answer 122

Multitasking allows for software tasks to be completed at the same time to ensure multiple elements can be completed immediately, it uses a system called time slicing which splits different tasks into small segments They can all be run one after the other, giving the element of multiple tasks being completed at the same time, instead of waiting for one operation to complete before moving on to the next task

Answer 123

Application programs and the hardware will communicate through a system within the operating system called an application programs interface(API) This API is a library interface which will share data between software to allow elements to process If any application is installed on the system, the Operating System will manage this process, it will allocate memory space and will control the application's data or devices, user access will also be managed

Answer 124

System security is just about how the operating system can stay protected and ensure that elements are monitored and actioned to ensure the system is secure. Some areas of security are: Creating/Deleting users for the system Providing access level rights, e.g. administrator rights over installing, modifying a system or accessing files or folders. This is compared to standard rights of just accessing and using software/files on the system. **Auditing** - this is keeping a log of file edits, deleted files, creation of files etc Protecting from threats, viruses, worms, malware or remote hacker attacks Security updates to fix patches in the operating system

Answer 125

Each user is provided with an account for access to the system. They will be provided with their username and then will need to create a password based on rules set out initially Each account will then be granted different levels of access, dependent on needs and level of security. This will also monitor login activity and even log users out if they have been inactive for a while.

Answer 126

Application Software must talk to the operating system, this will then allow it to interact with the hardware The hardware will then process and send the information to the operating system which then directly talks back to applications software in a continuous loop Firmware is the process between the Operating System and Hardware When a computer initially first loads up, it has to explore the ROM for its initial boot-up instructions. These are contained in a Bootstrap loader The initial process is handled by the basic input/output system (BIOS) which is known as firmware. This will provide some low-level control for all devices Once complete these are sent to RAM to be processed by the operating system Overall this creates an extra layer which is to ensure that initially the hardware devices e.g. keyboard are available and can be communicated directly with the operating system

Answer 127

An interrupt is a signal from a device or software to the processor. This will cause the processor to temporarily stop so that it can service the interrupt.

Answer 128

Hardware Interrupt - this is caused by a hardware device such as a hardware failure e.g. pressing a key on the keyboard moving the mouse Software Interrupt - this occurs when an application stops or requests services from the OS e.g. a program is not responding division by zero two processes trying to access the same memory location

Answer 129

Whenever an interrupt is initiated the status of this task is saved to the interrupt service routine. The interrupt service routine is simply added to a particular area where a certain set of instructions are sent that will need to be fetched, decoded and executed to complete the commands of the interrupt As a result, the current registers will need to be changed at this point to accommodate the interrupt The interrupt will be executed instead of the original instructions When the interrupt is received the current values that were held in the registers are copied back to the RAM in an area known as a stack These values are pushed onto the stack and are added to the top of the stack frame, which will save them for later retrieval when the interrupt is complete.

Answer 130

There is a possibility that an interrupt can also be interrupted which is known as a division by zero. Due to the system in RAM with stack frames, the current interrupt would be moved to the bottom of the stack frame to complete the main interrupt initially

Answer 131

Utility programs perform specific tasks related to computer functions, resources, files and security. They help to configure the system, analyse how it is working and optimise it to improve its efficiency.

Answer 132

Anti-Virus - Scans the computer system and ensures that files are quarantined so that they can be removed by the user Encryption - uses an algorithm to scramble (encrypt) a file according to the key which is used to make the file unreadable; the key is needed to decrypt the file back to its original form so it can be read Firewall - monitors network traffic and blocks unauthorised access. Criteria is set and if the data meets the criteria it is accepted otherwise it is rejected

Answer 133

**System Clean-Up Tools** – to search for and remove files no longer needed, to reduce space and speed up access to the system **Disk Defragmentation Tools**- it is used to rearrange the parts of files on the disk drive: when a file is saved to the disk, parts of the file might be saved in different areas of the disk, these tools try to move all the parts to the same area for quicker access

Answer 134

**File Compression Software** – to make files smaller so that they take up less storage space and can be transmitted to other users more easily File backup utilities **Full Backup** - stores all files and software on the system **Incremental Backup** - only backs up the files and software that have been added since the last backup

Answer 135

Application software provides the services that the user require

Answer 136

**Word Processing Software** This allows users to create written documents e.g. letters, reports etc **Spreadsheet Software** This allows users to perform numerical calculations and function to create automation for all mathematical elements e.g. budgeting, accounting, stock counts etc **Presentation Software** This allows users to create interactive and multimedia presentations to show to an audience e.g. sales pitches, launching of products etc **Multimedia Software** This is used to create multimedia and interactive content for a number of purposes, it explores text, audio, images, video, sound and animations e.g. image manipulation, editing a video etc **Web Browsers** This allows the user to access the internet and use the world wide web

Answer 137

* Low level language is a language closer to the language processed by the computer. * They may contains menemonics * Examples are assembly language and machine code

Answer 138

* Programmers can directly manipulate the hardware. * Programs are memory efficient * It is machine independent so there is no requirement for the program to be portable * No requirement for a compiler/interpreter * Quicker to execute

Answer 139

* Low-level languages are more difficult to write and understand * Machine dependent and cannot be added to different specification machines * More prone to errors * Knowledge of computer architecture is key to program effectively * Much harder to decode

Answer 140

High Level Languages are programming languages which use English-like statements which allow users to program with easy to use code, allow for clear debugging and once programs are created they become easier to maintain High level languages were needed more due to the development of processor speeds and memory capacity increasing Examples of these languages are Python, C#, Java etc

Answer 141

* It is easier to read and write therefore the programmer is less likely to make mistakes * It is easier to debug so it takes less time to find and correct errors. * It is machine independent so it can be used in any computer. * Programmer can focus on the problem instead of the manipulation of memory/hardware

Answer 142

* The programmer may not be able to make use of special hardware. * Need a compiler/interpreter and programs can take longer to execute. * The program may be less efficient and take considerable memory. * The user is not able to directly manipulate the hardware

Answer 143

Programmers who use assembly language do so for the following reasons: * Need to make use of specific hardware or parts of the hardware * To complete specific machine dependent instructions * To ensure that too much space is not taken up in RAM * To ensure code can completed much faster Assembly languages allow programmers to program with mnemonics. e.g. * LDA Load - this will ensure a value is added to the accumulator * ADD Addition - this will add the value input or loaded from memory to the value in the accumulator * STO, Store - stores the value in the accumulator in RAM This is used rather than binary code which allowed continuation of working directly with the hardware but removed an element of complexity A mnemonic is received by the computer and it is looked up within a specific table An assembler is needed here to check the word so that it can be converted into machine code If a match from the word is found e.g. STO the word is replaced with the relevant binary code to match that sequence

Answer 144

Compiler translates a high level language to a machine code in one go so that it can be understood by the computer system. It translates all the code before it is executed It creates an executable file If there is any **error** while the compiler is trying to compile then it will create an error report that will display all the errors in the code that need to be corrected before it can be executed.

Answer 145

* Run quickly as the program as the source code has been stored to be translated * Compilers optimise the code, this code will run quicker and take up less memory space * Original source code will not be seen, which is ideal for programmers to stop work being copied

Answer 146

* Due to all code being compiled at the same time there must be enough memory space to handle this, if not and virtual memory is used it can be much slower * If there are errors in the code the compiler will not identify directly where the error lies, making it difficult to debug * It is designed solely for one specific processor * If the program is changed it must be recompiled

Answer 147

* This is the method that directly sends the high level language to the machine code. * This will translate one line of code and then executes it before moving on to the next line, if an error occurs the program will stop and an error message will occur. * Once the error message is fixed, the program can carry on running from where the error occurred.

Answer 148

Program will always run, it will just stop when it finds a specific syntax error in the code It is easier to debug and understand where particular code has gone wrong Interpreters do not store instructions and are not stored for later use, this means they require less RAM to process the code

Answer 149

* Each line of code has to be interpreted separately by the CPU, which can lead to slower execution * Every time the program is run it has to be translated, due to no instructions being stored * They cannot optimise code, it is translated and executed as it is

Answer 150

An integrated development environment (IDE) is software that provides useful functions for a programmer writing a computer program. Use by programmers to aid the writing of their program.

Answer 151

* **Code editors** - this will allow users to write and manipulate source code, it includes features such as auto-completion and auto-correction of code, bracket matching, syntax checks etc * **Run-time environment** - to allow the program to run and see its corresponding output * **Built-in interpreter/ compiler** - which compiles or interprets the code * **Error diagnostics** - highlight particular areas of code or provide direct error messages where the error may have appeared e.g. indentation errors etc * **Auto-completion** * **Auto-correction** * **Prettyprint**

Answer 152

* Memory addresses and other hardware related values * Representation of colour values * Error messages * Memory dump * Debugging * IP addresses * ASCII / Unicode * Assembly language * URLs

Answer 153

* Easier to read and write * Less bits = less prone to error * Easier to debug

Answer 154

* Character set is a collection of all the characters and symbols that can be represented by a computer. * Each character and symbol is assigned a unique binary value. * It is used to represent text in binary; text is converted to binary to be processed by the computer.

Answer 155

One of the most commonly used character sets is the **American Standard Code for Information Interchange** (ASCII), which assigns a unique 7-bit binary code to each character, including uppercase and lowercase letters, digits, punctuation marks, and control characters. E.g. The ASCII code for the uppercase letter 'A' is 01000001, while the code for the character '?' is 00111111.

Answer 156

Unicode was developed as a character encoding standard that allows for a greater range of characters and symbols than ASCII, including different languages and emojis Unicode uses a variable-length encoding scheme that assigns a unique code to each character, which can be represented in binary form using multiple bytes E.g. The Unicode code for the heart symbol is U+2665, which can be represented in binary form as 11100110 10011000 10100101

Answer 157

ASCII has limitations in terms of the number of characters it can represent, and it does not support characters from languages other than English.

Answer 158

As Unicode requires more bits per character (Each character is encoded using more bits) than ASCII, it can result in larger file sizes and slower processing times when working with text-based data.

Answer 159

Sound is a type of analog signal that is captured and converted into digital form to be processed by a computer.

Answer 160

To convert sound into digital form, a process called sampling is used. This involves taking measurements of the sound wave at regular intervals and converting these measurements into binary data

Answer 161

Sample rate is the number of samples taken per second.

Answer 162

The sample resolution refers to the number of bits per sample, which determines the level of detail and accuracy of each sample.

Answer 163

The **accuracy of the recording** increases as the sample rate and resolution increase, but also increases the **file size** of the digital sound.

Answer 164

A bitmap image is made up of a series of pixels.

Answer 165

The resolution of an image refers to the number of pixels in the image or per set area. A higher resolution image has more pixels and is, therefore, sharper and more detailed but also requires more storage space.

Answer 166

A pixel is a single square of one colour and is the smallest component of the image. Each pixel can be represented by a binary code, which is processed by a computer. Pixels are arranged together in a grid.

Answer 167

The colour depth of an image refers to the number of bits used to represent each colour. A higher colour depth means that more colours can be represented, resulting in a more realistic image but also requires more storage space.

Answer 168

* QUALITY * COLOR DEPTH

Answer 169

GROUP OF 4 BITS

Answer 170

* 4 bits in a **nibble** * 8 bits in a **byte** * 1024 bytes in a **kilobyte** * 1024 kibibytes in a **mebibyte** * 1024 mebibytes in a **gibibyte** * 1024 gibibytes in a **tebibyte** * 1024 tebibytes in a **pebibyte** * 1024 pebibytes in an **exbibyte**

Answer 171

The process of reducing the size of the file.

Answer 172

* Lossy compression * Lossless compression

Answer 173

* Less bandwidth required * Less storage space required * Shorter transmission time

Answer 174

* ZIP FILES * PDF FILES * PNG IMAGES * GIF IMAGES * FLAC AUDIO

Answer 175

* JPEG IMAGES * MP3 AUDIO * STREAMING MEDIA

Answer 176

A compression algorithm is used to reduce the file size without permanently removing any data. Repeated patterns/character in the file are identified and indexed ( index involves assigning unique codes to each data and then using these codes to represent the data efficiently) The data is replaced with the index and positions stored The number of times the pattern appears is also stored Techniques like run-length encoding (RLE) and Huffman encoding are the example of lossless compression.

Answer 177

* A compression algorithm is used. * Lossy compression reduces the file size by **permanently removing redundant data** from the file. * This method is often used for images and audio files where minor details or data can be removed without significantly impacting the quality. For example, sound in the background that cannot be heard by human ears. * Techniques like downsampling, reducing resolution or colour depth, and reducing the sample rate or resolution are used for lossy compression * File **cannot be restored back.** * The amount of data removed depends on the level of compression selected and can impact the quality of the final file

Answer 178

**LOSSY COMPRESSION** * QUALITY/DATA LOSS * FILES CANNOT BE RESTORED BACK * SMALLER FILE SIZE * FASTER TRANSMISSION RATE **LOSSLESS COMPRESSION** * NO QUALITY LOSS * FILES CAN BE RESTORED BACK * LARGER FILE SIZE IN COMPARE TO LOSSY * SLOWER TRANSMISSION RATE IN COMPARE TO LOSSY

Answer 179

Data and commands are inputted by the user using an input device, the central processing unit (CPU) processes data by executing instructions and the results are outputted to an output device.

Answer 180

The Arithmetic Logic Unit(ALU) performs the calculations required to execute the instructions, these include ADD and SUBTRACT The ALU also carries out logical operations such as COMPARE The ALU has a built-in register where it stores interim results of calculations it performs.

Answer 181

The control unit sends control signals that manage the flow and transfer of data and instruction within the CPU. The Control Unit also decodes instructions using an instruction set and controls the clock speed.

Answer 182

A microprocessor is a type of integrated circuit on a single chip. The purpose of a microprocessor is to process data and execute instructions.

Answer 183

* Program Counter (PC) * Memory Address Registers (MAR) * Memory Data Register (MDR) * Current Instruction Register (CIR) * Accumulator

Answer 184

stores the address of the next instruction to be fetched from memory

Answer 185

Registers are small memory locations within the CPU, which temporarily store data needed to execute an instruction.

Answer 186

stores the address of the instruction or data to be fetched from or written to memory

Answer 187

Temporarily stores the results of the calculations performed by the arithmetic and logic unit

Answer 188

Components within the CPU and wider computer system are connected by buses. These are wires down which electronic signals and data travel. The different buses are collectively called the system bus.

Answer 189

* The **data bus** transmits data from the CPU to memory or input/output controllers (OR CAN WRITE / between components in the CPU). It is bidirectional which means data can travel in both directions * The **address bus** transfers addresses from the CPU to memory. It is unidirectional which means addresses only go from the CPU to memory(OR CAN WRITE / between components in the CPU). * The **control bus** transfers control signals from the control unit to other components in the computer system such as memory or input/output controllers. The control bus is bidirectional.

Answer 190

The memory address of the instruction to be fetched is stored in the MAR and is sent down the address bus. The data at the memory address is transferred back to the CPU, via the data bus, where it is stored in the MDR Data from MDR is sent to ALU to be executed ALU performs calculation and logical operations on data and it stores the interim results of calculations in its built-in register. After calculations, ALU sends data to MDR Data is sent from MDR to be written to RAM

Answer 191

Stores the data that has been fetched from memory or being written to memory Data from MDR is sent to ALU to be executed

Answer 192

An instruction set is a list of all the commands that can be processed by a CPU and the commands are machine code. Each command has a unique binary code

Answer 193

An embedded system is a computer system with either one function or limited specific functions built within a device. Its purpose is to control the device and allow a user to interact with it It runs on firmware and does not have additional peripherals

Answer 194

INPUT DEVICE ARE THE DEVICE THAT ALLOWS DATA TO BE ENTERED.

Answer 195

Core is used to perform a fetch-decode-execute cycle and to process / execute an instruction .

Answer 196

A dual-core processor has two cores A quad-core processor has four cores

Answer 197

* KEYBOARD * MOUSE - OPTICAL MOUSE * BARCODE SCANNER * TOUCH SCREEN ((resistive, capacitive and infra-red) * DIGITAL CAMERA * MICROPHONE * QR CODE * two-dimensional (2D) and three-dimensional (3D) scanners

Answer 198

Multiple cores enables multitasking (running more than one program at the same time) Some programs cannot be split between cores The more cores a computer has the more instructions that can be executed per second simultaneously resulting in better performance.

Answer 199

The clock speed is how many instructions the core can execute each second The clock speed is measured in Hertz Modern cores can execute billions of instructions per second

Answer 200

Cache is a small amount of memory situated within or close to the CPU with very fast read/write speeds It is used for storing **frequently used** instructions/data,**recently used** instructions, and instructions that are **to be fetched and executed** next in a process.

Answer 201

The impact of increasing the amount of cache is that more data can be stored there and accessed faster than if it was in RAM which improves the performance of the CPU.

Answer 202

A digital camera works by capturing light and converting it into a digital image Light enters the camera through the lens, it reaches an image sensor where it is split into millions of pixels (small squares). Each pixel measures light intensity which is converted into binary and represents a colour. Digital cameras are integrated into smartphones , used in security systems and by professional photographers to create high quality digital images An advantage of digital cameras is they show a preview of the image They also instantly create an image which can then be easily duplicated and transmitted via bluetooth or WiFi.

Answer 203

A keyboard is the most common device used for text-based data input They are connected either by a USB cable or wirelessly to the computer system They are built into laptops. Smartphones and tablets have virtual keyboards Each key on a keyboard has a peg underneath it which makes contact with a conducting membrane. This is then converted into an electrical signal to transmit a unique character code. USE - ENTERING TEXT.

Answer 204

* Intuitive * No moving parts * Easy to use

Answer 205

* UNIVERSAL * EASY TO USE

Answer 206

A mouse use a laser to detect and track movement, this is then processed by a microprocessor which interprets the movement and replicates it when moving a virtual cursor on-screen Items can be selected or moved using the left mouse button, whilst the right button usually displays additional menus They can be wired or wireless They are used to control the cursor in a Graphical User Interface (GUIs) They are simple to use and provide the user with an intuitive way to navigate the computer They are reliable due to no moving parts USE- Navigating a GUI and Making selections and entering commands.

Answer 207

Barcodes are a series of black and white bars which represent a code A barcode reader shines a red laser at the barcode to read the data it represents The light from the **white lines is reflected** back **Black lines absorb the light** so less is reflected The different levels of reflection are converted into a binary value which can be processed by a microprocessor A barcode reader can be handheld or built into a larger machine such as a self-service checkout at a supermarket Barcodes can be used in many ways such as identifying a product being sold or tracking a package through the delivery process

Answer 208

Instant preview and image

Answer 209

A computer microphone works by converting sound waves into electrical signals that can be processed by the computer. They can capture any real world sound and convert it into digital data which can be stored, duplicated or modified Microphones are used to record music, telephone calls, communicate online and dictation

Answer 210

A QR code is a visual representation of data using **black and white squares** QR codes can represent over 7000 digits whereas a barcode represents up to 30 digits QR codes are scanned by a camera (often on a mobile device) A piece of software convert the squares into binary data QR codes often link to a website where more information can be found They can also be used to advertise products, share contact details, provide promotional codes, train tickets, and event tickets.

Answer 211

Resistive screens consist of two conductive layers which are separated by a small gap. The top layer is flexible. When the screen is touched the two layers connect, completing a circuit.

Answer 212

Made up of a protective layer, a transparent conductive layer and a glass substrate. Touching the screen changes the electrostatic field of the conductive layer CAPACITIVE PROCESS Electrical field/charge is spread across the screen − Sensors are located around the screen and are used to read the electric field − When finger touches screen, the charge/ is transferred to the user as it is affected by the conductivity of another object − Coordinates of touch determined/calculated/measured.

Answer 213

**BENEFITS** * Cheap to produce. * Resistant to surface contaminants * Can be activated with nearly every object (stylus, finger, gloved hand **DRAWBACKS** * Have lower accuracy compared to other touch screen types. * Less responsive * Made of polymer so is vulnerable to scratches * Does Not support multi-touch facility * Poor visibility in strong sunlight

Answer 214

**BENEFITS** Excellent image quality Unlimited touch-life/ ALLOW MULTI TOUCH Scale well Very durable **DRAWBACKS** Sensitive to interference from light, water, snow SENSITIVE TO ELECTROMAGNETIC RADIATION SURFACE CAPACITIVE SCREEN ONLY WORKS WITH BARE HANDS OR A SPECIAL STYLUS

Answer 215

LEDs shine infrared light across a screen forming a matrix. When the screen is touched the beams are interrupted. The sensor will send the reading that it detected to the microprocessor that calculates where the screen was touched.

Answer 216

**BENEFITS** * Excellent image quality, * High precision * Durable * Allows for multiple touches at the same time **DRAWBACKS** * Requires a bare finger or stylus for activation * Sensitive to water and moisture

Answer 217

A two-dimensional (or flat-bed) scanner shines a bright strip of light over a document and the reflected light is captured by mirror and lenses. Reflected light is measured for each pixel. This data is converted into binary data so the document can be digitally recreated and stored in a computer. 2D scanners can be used for creating digital versions of documents or photographs - Reading passports at airports

Answer 218

A three- dimensional laser scanner shines a light over an object. The geometry and dimensions are recorded so the object can be recreated digitally The digital 3D model can be modified using specialist software A 3D printer could then print out the model 3D scanners can be used to create 3D models for use with computer-aided design (CAD) software Creating replicas with 3D printers Typical uses of 3D scanners and printers are dentistry, product development, medical

Answer 219

* actuator * digital light processing (DLP) projector * inkjet printer * laser printer * light emitting diode (LED) screen * liquid crystal display (LCD) projector * liquid crystal display (LCD) screen * speaker * 3D printer

Answer 220

Used to project computer outputs onto a large screen and give presentations in both business and education settings. It uses many small mirrors to reflect light towards a lens. This will display an image.

Answer 221

* Digital light processing (DLP) projectors * Liquid crystal display (LCD) projectors

Answer 222

DLP systems use millions of micro-mirrors arranged in a grid on a microprocessor within the projector. Light is shone through colour filters and the mirrors. The position of the mirrors can be altered to change the intensity of the light.

Answer 223

LCD projectors use three mirror filters to separate an image into red, green and blue wavelengths. The three images are then combined to produce the full colour image which is passed through the lens on to the wall/screen.

Answer 224

**ADVANTAGE** * Higher contrast ratios. * Smooth video * Higher reliability * Smaller and lighter * Better suited to dusty atmospheres than LCD projectors **DISADVANTAGE** * Image tends to suffer from “shadows” when showing a moving image * DLP do not have grey components in the image * The colour definition is not as good as LCD projectors

Answer 225

**ADVANTAGES** * Give a sharper image than DLP projectors * Contrast ratios are not as good as DLPs * Better colour saturation and intensity than DLP projectors **DISADVANTAGES** * Have a limited life * Use less power and generate less heat * LCD panels degrade over time. * Quieter running that DLP

Answer 226

* INKJET PRINTER * LASER PRINTER * 3D PRINTER

Answer 227

Have a print head which moves across the page Spray liquid ink droplets from ink cartridges through very fine nozzles onto the paper (these are in the print head) The droplets can be piezoelectric or thermal bubble technology Inkjet printers produce high quality hard copies of digital images or documents

Answer 228

* Great for bright colours and images * Widely used in homes and home offices with lower print volumes

Answer 229

* Have large toner (dry ink) cartridges and large paper trays * Use positive and negative charges to make the toner particles stick to piece of paper, heat is then used to bond the particles to the paper * Are often used in business and education setting

Answer 230

**ADVANTAGES** * Are very fast when making multiple copies of a document -[PRINTS FASTER] * Are useful for high volume print jobs for example producing leaflets * Have a low running cost per page. -[CHEAP] * It prints text at a high quality * Colour fast **DISADVANTAGE** * Expensive to purchase printer * Toner is expensive * Print images at a lower quality * Can be quite large in size

Answer 231

3D printers create 3D models of a digital model by depositing layers of material, such as plastic or resin, on top of one another to slowly build up a 3D object They allow for precision and can be used in medicine to create prosthetics and blood vessels 3D printers can be used to create rapid prototypes Models can be transmitted digitally and then models printed out all across the world.

Answer 232

* It stands for Liquid Crystal Display screens. * LCD screens are made up of millions of tiny liquid crystals. * The display is made of pixels arranged in a matrix * The display requires backlighting * They are used for TVs, monitors, tablets and phones