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Learn about visual design elements of human-computer interfaces such as colours, interaction, location hierarchy, messages (help, error) and typography (style, size). Based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced National in Computing (H029 / H129) (AAQ - Alternative Academic Qualification). Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F160: Fundamentals of Application Development Certificate: Computing: Application Development (H029 / H129) 5.2 - Human Computer Interface Visual Design Considerations Watch on YouTube : Visual design considerations When creating a human-computer interface , there are several visual design considerations that the development team must take into account, such as the use of colour and the style of typography . You need to know how each visual design consideration is used when designing human-computer interfaces and how these interfaces can be improved to be more effective . As with most topics, it is also vital to consider how client requirements may impact changes related to visual design , for example, using larger text for users with visual impairments . Visual Design Considerations Visual Design Considerations Colours are used to define the visual appearance of the interface . This includes background colours , button colours , icons and text . Interaction refers to how users control or respond to the system through input methods like clicking , tapping , swiping , typing or speaking . Location hierarchy is about the placement and organisation of interface elements based on importance . Messages are displayed to provide feedback , guidance or explanations - such as confirming actions , explaining errors or offering help . Typography includes the choice of font types and the size , spacing , weight (boldness) and alignment of text . Q uesto's Q uestions 5.2 - Human-Computer Interface Visual Design Considerations: 1. Explain how colours can be used effectively in human-computer interfaces . [4 ] 2. Describe what is meant by location hierarchy and why it is important to consider . [4 ] 3. Suggest specific visual design considerations an application developer should consider when making software for a primary school in Dubai . [ 5 ] Approximately 1 in 12 men and 1 in 200 women are colour-blind , meaning good designers should include text or icons rather than relying on just colour to convey meaning . D id Y ou K now? 5.1.2 - Types of Devices Topic List 5.3 - HCI Designs & Diagrams

Learn about the role of different server types including file, application, print, email, mail servers and the hypervisor. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 3.1 - Server Types Exam Board: OCR Specification: 2016 - Unit 1 What is a server? A server is a powerful dedicated system on a network . It requires increased memory , storage and processing power than traditional computer systems to fulfill its role across the network. Servers need to be scalable - this means they must be adaptable and able to efficiently manage the needs of connected systems if more are added or some are removed . Servers have different roles so a company may use multiple , separate server types within their organisation, each with a specific purpose . Having separate servers is costly but beneficial as if one loses connection , others may still be usable . Also a server will be more efficient if it is only managing one resource (e.g. printers) at a time . File Server A file server centrally stores and manages files so that other systems on the network can access them. The server provides access security , ensuring that only users of the appropriate access level can access files. File servers can be used to automatically backup files , as per the organisation's disaster recovery policy. Using a file server frees up physical storage space within a business and can provide printing services too. Printer Server These servers control any printers on a network and manage printing requests by sending the document to an appropriate printer. Print servers use spooling to queue print jobs so that they are printed when the printer is ready. If a fault occurs with a certain printer, work can be automatically diverted to another available printer. Application Server These servers allow users to access shared applications on a network. All users will be able to access common applications like email software or word processing, but the server will also restrict certain applications to those with invalid access levels (such as hiding financial databases from employees outside of the finance department). Application updates can be simply deployed to the application server only , avoiding individual updates for each system and saving a lot of time . Installers can be hosted on an application server, allowing the software to be easily installed on other connected machines . Database Server These servers manage database software that users on the network can access and use to manipulate data . Data held on the server will be stored in a database accessible from multiple connected computers . The data can be modified using query languages such as SQL. Storing data on a database server, rather than individual computers, is more reliable . A database server for a business also allows for scaling - for example, the database can be increased in size if the customer base grows. Web Server A web server manages HTTP requests from connected devices to display web pages on web browsers . A request (e.g. csnewbs.com) is sent to the web server. The server contains a list of known URLs and their matching IP addresses . The server contacts the server where the web page is held and delivers the web page to the client . Mail Server These servers send and receive emails using email protocols (SMTP & POP) allowing email communication between other mail servers on other networks. The server makes sure emails are delivered to the correct user on the network. Email servers can store company address books making internal communication easier for organisations. The server may have anti-spam functions to reduce junk mail. Hypervisor A hypervisor allows a host machine to operate virtual machines as guest systems. The virtual machines share the resources of the host , including its memory, processing power and storage space. This type of technology is called virtualisation . The guest machines are isolated so if one failed, the other guests and the hosts are not affected - demonstrating good security . The hypervisor optimises the hardware of the host server to allow the virtual machines to run as efficiently as possible. Q uesto's Q uestions 3.1 - Server Types: 1a. What is a server ? Why does it need to be scalable ? [2 ] 1b. Give two reasons why a company may use multiple , separate servers . [2 ] 1c. State the 7 types of server . [1 each ] 2. A medium-sized animation company working on a movie are considering buying a server. Describe each type of server and the different roles they have. a. File Server b. Printer Server c. Application Server d. Database Server e. Web Server f. Mail Server g. Hypervisor [4 each ] 3. What type of technology does a hypervisor use to control multiple virtual machines? [1 ] 2.7 - Protocols Topic List 3.2 - Virtualisation

Learn about the benefits and drawbacks of virtualization, as well as about cloud storage and virtual clients. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 3.2 - Virtualisation Exam Board: OCR Specification: 2016 - Unit 1 What is virtualisation? Virtualisation is the creation of a virtual version of a device , software , operating system or server . These virtual versions can then be run on a different physical computer system , such as a powerful server . There are many different types of virtualisation . Storage virtualisation combines multiple separate storage devices into acting and appearing like a single , central storage system . Using storage virtualisation improves scalability as further devices can join the storage system if more space is required . It also simplifies the management of storage across the network. Server virtualisation allows one physical server to be divided into and host multiple virtual servers , each running separately . Each virtual server operates independently , handling its own operating system and applications . This allows for resources to be used more effectively and improves the scalability and versatility of the physical server . Client Virtualisation (Virtual Clients) Client virtualisation is when several virtual desktops are run on a single server - think back to the hypervisor from 3.1 . A virtual client is a full desktop environment where the processing happens remotely . For example, where an operating system is managed and hosted centrally but displayed locally on a different computer. These are often known as 'dumb clients ' because the server does the processing for it , meaning it can have minimal resources like a slow processor and little memory / storage . General Benefits & Drawbacks of Virtualisation Benefits of virtualisation: Costs are cheaper in the long-term because money is saved by not purchasing multiple physical devices . Money is also saved due to less cabling and lower power consumption . If set up efficiently, it can be used for higher performance at a lower cost - "Do more with less" . Programs can be tested in a secure environment before main-system deployment. Simplified response to recover after a disaster because only the server needs to be fixed. Drawbacks of virtualisation: If not set up efficiently, users could face serious performance issues , as fewer servers do more work. If a single physical system fails , the impact will be greater . Initial set up is complex , requires technical knowledge and can cost a lot. Easier for hackers to take more information at once as the data is stored in the same place. Benefits of client virtualisation: All data is stored in one central location , making backup and disaster planning easier to manage . The whole system can be managed , secured and updated from the server , rather than from each individual system. Hardware costs will be reduced because the virtual clients do not store or process their own data , meaning they can be of a low spec . Users can have multiple virtual machines and log in remotely (from anywhere with internet access ). Drawbacks of client virtualisation: Users will be unable to work if network connectivity is lost . There is a high strain on the server as the virtual clients do not store or process data themselves . An increased load on the server might result in poor performance for each client, especially with multiple connections . As the data is stored in one location , there are security risks of unauthorised access if the server is not adequately protected . Server Virtual Clients Cloud Technology 'The cloud ' is storage that is accessed through a network , primarily the internet. A cloud server is an example of storage virtualisation as data may be stored across multiple physical devices . There are three different types of cloud storage: Private cloud is where a business will have its own data centre that employees can access. This allows for flexible and convenient data storage and gives the business control over data management and security . Users of the private cloud will not usually have to pay individually for access - but the company will need to spend a lot of money on set up and maintenance . Public cloud uses third-party service providers such as Google Drive or DropBox to provide storage over the internet . Public cloud is usually a pay-for-use service , where businesses will pay for specific amounts that they need. Data management and data security is maintained by the cloud provider and the business is dependent on them providing constant access and deploying effective security measures. Hybrid cloud uses a mix of on-site storage (private cloud) and third-party (public cloud) services . Organisations can move workloads between private and public clouds as their specific needs and costs change . A benefit of hybrid cloud is that it gives an organisation greater flexibility and data storage options. As an example, a company could use on-site or private cloud storage to hold sensitive information and third-party, public cloud services to hold less important data . Q uesto's Q uestions 3.2 - Virtualisation: 1. What is the difference between server and storage virtualisation ? [ 2 ] 2a. What is a virtual client ? [ 1 ] 2b. What are the advantages and disadvantages of client virtualisation ? [ 8 ] 3. Explain any further general advantages and disadvantages of using virtualisation , not covered in your answer to 2b. [4 ] 4. Describe the differences between private , public and hybrid cloud storage. [6 ] 3.1 - Server Types Topic List 3.3 - Network Characteristics

Learn about how to convert between the denary (decimal), binary and hexadecimal number systems. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). Exam Board: OCR 2.4a: Number Systems Specification: J277 Watch on YouTube : Binary and Denary Hexadecimal Number System Ranges Binary to Denary Denary to Binary Binary to Hexadecimal Hexadecimal to Binary Denary to Hexadecimal Hexadecimal to Denary What is binary? By now you should know that computer systems process data and communicate entirely in binary . Topic 2.3 explained different binary storage units such as bits (a single 0 or 1), nibbles (4 bits) and bytes (8 bits). Binary is a base 2 number system. This means that it only has 2 possible values - 0 or 1 . What is denary? Denary (also known as decimal ) is the number system that you've been using since primary school. Denary is a base 10 number system. This means that it has 10 possible values - 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 . Binary & Denary Convert from binary to denary: Convert from denary to binary: Hexadecimal What is hexadecimal? Hexadecimal is a base 16 number system. This means that it has 16 possible values - 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E and F . Hexadecimal is used as a shorthand for binary because it uses fewer characters to write the same value . This makes hexadecimal less prone to errors when reading or writing it , compared to binary. For example, 100111101011 in binary is 9EB in hexadecimal. Hexadecimal only uses single-character values. Double-digit numbers are converted into letters - use the table on the right to help you understand. Binary to hexadecimal: Hexadecimal to binary: Converting from denary to hexadecimal / hexadecimal to denary To convert from denary to hexadecimal or from hexadecimal to denary , it is easiest to convert to binary first . However, it is possible to convert directly from denary to hexadecimal or directly from hexadecimal to denary . The videos below explain both methods . Denary to hexadecimal: Hexadecimal to denary: Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube Q uesto's Q uestions 2.4a - Number Systems: 1. Explain why hexadecimal numbers are used as an alternative to binary . Use an example . [ 3 ] 2. Convert the following values from binary to denary : a. 00101010 b. 11011011 c. 01011101 d. 11101110 e. 01011111 [1 each ] 3. Convert the following values from denary to binary : a. 35 b. 79 c. 101 d. 203 e. 250 [1 each ] 4. Convert the following values from binary to hexadecimal : a. 11110101 b. 01100111 c. 10111010 d. 10010000 e. 11101001 [1 each ] 5. Convert the following values from hexadecimal to binary : a. C2 b. 8A c. DE d. 54 e. F7 [1 each ] 6. Convert the following values from denary to hexadecimal : a. 134 b. 201 c. 57 d. 224 e. 101 [1 each ] 7. Convert the following values from hexadecimal to denary : a. 32 b. A5 c. 88 d. C0 e. BE [1 each ] Click the banners below to try self-marking quizzes (Google Forms) on these topics. Binary to Denary: Denary to Binary: Binary to Hexadecimal: Hexadecimal to Binary: 2.3 - Data Units Theory Topics 2.4b - Binary Addition & Shifts

Learn database topics including entity relationships, keys, normalisation, capturing and exchanging data, SQL, referential integrity, transaction processing and ACID (atomicity, consistency, isolation, durability). Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 3.2 - Databases Specification: Computer Science H446 Watch on YouTube : Database Keys & Relationships Flat File & Relational Databases Capturing & Managing Data SQL Normalisation Referential Integrity & ACID Database Keys & Relationships A database is an organised collection of data stored in tables , where each table represents an entity such as a customer or product . Each table is made up of records ( rows ), which store information about individual instances of that entity , and fields ( columns ), which hold specific attributes like names or prices . A primary key uniquely identifies each record , while a foreign key links records between tables to create relationships . Secondary keys use indexing to speed up searches and data retrieval . Relationships between entities are shown using an Entity–Relationship ( ER ) diagram , which illustrates one-to-one , one-to-many and many-to-many connections between tables . YouTube video uploading soon Flat File & Relational Databases A flat file database stores all data in a single table or file , often in a simple format such as a spreadsheet or text file . It is easy to create and manage , making it suitable for small-scale applications . However, it can lead to data duplication and inconsistency because the same data may be repeated in multiple records . A relational database stores data in multiple related tables , linked together using primary and foreign keys . This design reduces data redundancy and improves data integrity by storing each piece of information only once . The main disadvantage is that relational databases are more complex to design and maintain , requiring more processing power and knowledge to manage effectively . YouTube video uploading soon Capturing & Managing Data Data can be captured from sources such as forms , Optical Character Recognition (OCR ), Optical Mark Recognition (OMR ) and sensors . These methods allow information to be collected automatically or manually and entered into a computer system for processing . Data can be selected and filtered using tools like Query By Example (QBE ) or SQL commands . This allows users to retrieve only the specific records that meet certain criteria from a database . Data management involves manipulating stored information , such as performing arithmetic functions or adding , editing and deleting records . This ensures that the data remains accurate , up to date and useful for decision-making . Data can be exchanged (shared ) between systems using common file formats such as CSV and JSON . These formats make it easier to transfer data between different software applications or platforms while maintaining structure and meaning . YouTube video uploading soon Database Normalisation Database normalisation is the process of organising data in a database to reduce redundancy and improve data integrity . It ensures that each piece of data is stored only once , making updates and maintenance more efficient and reducing the risk of inconsistent data . Normalisation is measured in 'forms ': First Normal Form (1NF ): Ensures that all fields contain atomic (indivisible ) values and that there are no repeating groups in a table. Each table must have a primary key . Second Normal Form (2NF ): Builds on 1NF by ensuring that all non-key attributes depend on the entire primary key , removing partial dependencies . Third Normal Form (3NF ): Builds on 2NF by removing transitive dependencies , meaning non-key attributes depend only on the primary key and not on other non-key attributes . YouTube video uploading soon Structured Query Language (SQL) SQL ( Structured Query Language ) is used to create , manage and manipulate data in databases . It allows users to retrieve specific data using commands such as SELECT , FROM and WHERE , often combined with logical operators like AND and OR to filter results . The LIKE command and wildcards such as * and % are used to search for patterns within text data . SQL also supports data modification through commands like INSERT (to add data ), DELETE (to remove data ) and DROP (to delete entire tables ). More advanced queries can use nested SELECT statements or JOIN commands to combine data from multiple tables for more complex analysis . YouTube video uploading soon Referential Integrity & ACID Referential integrity ensures that relationships between tables in a relational database remain consistent . It means that a foreign key in one table must always refer to a valid primary key in another table . Transaction processing refers to the handling of a sequence of database operations (a transaction ) that must be completed fully or not at all . It ensures that databases remain accurate and consistent even if errors or system failures occur during the process . The ACID rules define the key properties of reliable transactions : Atomicity : The transaction is all or nothing - it either completes fully or not at all . Consistency : The database must remain valid before and after the transaction . Isolation : Transactions are independent , so one cannot interfere with another . Durability : Once completed , a transaction’s changes are permanent , even if the system crashes . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Database Keys & Relationships: field, record, table, primary key, secondary key, indexing, foreign key, entity relation (ER) diagram, one-to-one, one-to-many, many-to-many, flat file database, relational database Capturing & Managing Data: form, OCR, OMR, sensor, query by example, SQL, CSV, JSON, electronic and non-electronic data transfer SQL: SELECT, nested SELECT, FROM, WHERE, LIKE, AND, OR, DELETE, INSERT, DROP, JOIN, wildcards (* and %) Normalisation: first normal form (1NF), second normal form (2NF), third normal form ( 3NF), partial dependency, non-key dependency Referential Integrity & ACID: referential integrity, ransaction processing, ACID (atomicity, consistency, isolation, durability), record locking, redunancy D id Y ou K now? In 2013 the web portal / search engine company Yahoo! was hacked , with all 3 billion user accounts in their database compromised - the largest hack in history . Personal details such as names , email addresses and hashed passwords were taken , causing major reputational and financial damage to the company . 3.1 - Compression & Encryption A-Level Topics 3.3 - Networks

Learn about the two types of language levels, high level and low level, including explanations and examples. Based on the 2020 Eduqas (WJEC) GCSE specification. 7.1: Language Levels Exam Board: Eduqas / WJEC Specification: 2020 + There are two types of programming languages used within computer systems: High-Level Languages Why do programmers use high-level languages? H igh-level programming languages use code written in a way that is similar to a natural human language , such as English, making it easier to understand and use the language. Using high-level languages leads to fewer errors and allows for more powerful and complex commands compared to low-level languages. However, a high-level language must be translated into machine code (binary) before it can be run, as high-level languages cannot be executed directly by the CPU . Popular high-level languages: PYT HON C++ Ja v a Visual Basic Low-Level Languages Low-level languages do not closely resemble a natural human language , making it harder for humans to understand and write in. Low-level languages are used when a program must be executed quickly or when programmers need to write code that interacts directly with the hardware , such as device drivers. There are two types of low-level language : Machine Code This is the pure binary code that computers can directly process and execute . It is extremely tedious and difficult for humans to understand and write machine code. However, machine code can be used when a programmer needs to perform a very specific command that can't be done in a high-level language. Machine code will be executed faster than high-level programs because it is already in a format the CPU can execute and does not need to be translated . 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 0101 0100 1010 1010 1010 1010 1111 1110 0010 1001 0100 1001 0010 0111 0111 0101 0011 1010 1000 0101 0110 0111 0000 1010 1010 0011 1101 1001 0010 1101 0010 0100 1001 0011 1010 1001 0101 0101 0010 0101 0111 0101 0101 1000 1011 0111 Assembly Language Assembly language uses specialised command mnemonics to perform actions . See the Assembly Language section in the programming tab for a list of mnemonics such as INP , OUT and HLT . Assembly language is preferred by many programmers over machine code because it is easier to understand and spot errors . It is faster to execute than high-level languages and, like machine code, can be used to directly control the CPU . Q uesto's Q uestions 7.1 - Language Levels: 1a. Describe three reasons why programmers use high-level languages . [ 3 ] 1b. Explain one limitation of using high-level languages . [2 ] 2a. Describe a key difference between low-level languages and high-level languages . [ 2 ] 2b. Describe when a low-level language would be used instead of a high-level language . [2 ] 2c. Describe an advantage and a disadvantage of writing directly in machine code . [2 ] 2d. Describe what assembly language is. Give one benefit to using assembly language instead of machine code and one benefit to using it instead of a high-level language . [3 ] 3. Compare high-level and low-level languages by stating which is: a. Easier to understand [ 1 ] b. Requiring translation [ 1 ] c. Quicker to execute [ 1 ] INP STA Number1 OUT HLT Number1 DAT 6.2 - Utility Software Theory Topics 8.1 - Programming Principles

Learn how to use logical operators in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 4c - Logical Operators AND Operator The AND operator is used to execute certain code if more than one thing is true . AND is commonly used with account logins - both the username AND the password must be correct . The example below requires both a secret word and a secret number to be correct: print ( "To enter you need the secret word and the secret number!" ) word = input ( "What is the secret word? " ) number = int ( input ( "What is the secret number? " )) if word == "solitude" and number == 2011: print ( "Correct! You may enter!" ) else : print ( "Incorrect! Get out of here!" ) If no part or only some of the if statement is true then the indented code will not run : To enter you need the secret word and the secret number! What is the secret word? solitude What is the secret number? 4503 Incorrect! Get out of here! To enter you need the secret word and the secret number! What is the secret word? windhelm What is the secret number? 1021 Incorrect! Get out of here! Only If all parts of the if statement are true will the indented code be executed : To enter you need the secret word and the secret number! What is the secret word? solitude What is the secret number? 2011 Correct! You may enter! Logical Operators Task 1 ( Three Easy Questions) Ask the user three easy questions and print a special response if they get all three correct . Use the and operator to see if their answer for all each of the questions is correct. You must use a unique variable nam e for each of your inputs (it can't be 'answer' for all three, for example). Example solutions: What is the capital of Germany? Berlin What is the chemical formula for water? H20 What year did World War Two end? 1945 You absolute genius! What is the capital of Germany? Vienna What is the chemical formula for water? W20 What year did World War Two end? 1945 Bit awkward, I thought you'd do better... OR Operator The OR operator is used to execute certain code if one of several statements is true . The program below is checking if either a , e , i , o or u were entered. letter = input ( "Enter a letter: " ) if letter == "a" or letter == "e" or letter == "i" or letter == "o" or letter == "u" : print ( "You entered a vowel." ) else : print ( "You entered a consonant." ) Enter a letter: f You entered a consonant. Enter a letter: e You entered a vowel. It is important that you re-write the variable and operator (e.g. letter ==) each time you use 'or' . It will not work if you just write: if letter == “a” or “e” or “i” or “o” or “u”: Logical Operators Task 2 ( Twins?) Ask the user to enter their favourite colour and then ask them their age . If their favourite colour is the same as yours AND their age is the same as yours then print “Snap! Are you my twin?” . If only one of the statements is true (use the OR operator) then print “Spooky! You’re a bit like me.” . Add an else statement to print “We’re not so similar, you and I.” if there's nothing in common. Example solutions: What's your favourite colour? green What's your age? 15 Snap! Are you my twin? What's your favourite colour? blue What's your age? 15 Spooky! You're a bit like me. What's your favourite colour? red What's your age? 16 We're not so similar, you and I. ⬅ 4b - Mathematical Opera tors Sectio n 4 Practice Tasks ➡

Learn about malware such as viruses, worms, trojans, spyware, keyloggers and ransomware. Also, learn about phishing, data theft, interception and cyber attacks including SQL injection, IP address spoofing, DDoS attacks and brute force. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.8: Cyber Threats Exam Board: Eduqas / WJEC Specification: 2020 + 3.8a: Malware What is malware? Malware is any type of harmful program that seeks to damage or gain unauthorised access to your computer system. Virus A virus can replicate itself and spread from system to system by attaching itself to infected files . A virus is only activated when opened by a human . Once activated, a virus can change data or corrupt a system so that it stops working . Worm A worm can replicate itself and spread from system to system by finding weaknesses in software . A worm does not need an infected file or human interaction to spread. A worm can spread very quickly across a network once it has infiltrated it. Trojan A trojan is a harmful program that looks like legitimate software so users are tricked into installing it . A trojan secretly gives the attacker backdoor access to the system . Trojans do not self replicate or infect other files. Spyware Spyware secretly records the activities of a user on a computer. The main aim of spyware is to record usernames, passwords and credit card information . All recorded information is secretly passed back to the attacker to use. Keylogger A keylogger secretly records the key presses of a user on a computer. Data is stored or sent back to the attacker. The main aim of a keylogger is to record usernames, passwords and credit card information . Keyloggers can be downloaded or plugged into the USB port . Ransomware Ransomware locks files on a computer system using encryption so that a user can no longer access them. The attacker demands money from the victim to decrypt (unlock) the data . ? ? ? ? Attackers usually use digital currencies like bitcoin which makes it hard to trace them. 3.8b: Data Theft Phishing Phishing is the method of misleading individuals or organisations into sharing sensitive information (such as passwords or bank details ), often through the use of emails . Phishers may pose as a trusted company like Amazon or YouTube to direct users to open malicious attachments or encourage them to follow fraudulent links to steal their data . Social Engineering Social engineering means to trick others into revealing their personal data by posing as a trusted source . For example, impersonating an IT technician of a school via email and asking for a student's username and password . Interception This is when data packets on a network are intercepted by a third party (e.g. a hacker) and copied to a different location than the intended destination. Software called packet sniffers are used to intercept and analyse data packets. Physical Theft Computer systems (e.g. laptops) or storage devices (e.g. USB stick) may be stolen in public or from offices. Unwanted systems and storage media should be disposed of securely as data could be stolen from discarded information , such as old CDs or even printed paper. 3.8c: Online Threats & Attacks Hacking Hacking is the method of exploiting weaknesses in a system or network to create, view, modify or delete files without permission. A hacker is anyone who gains access to data or systems that they do not have authority to access. DoS Attack A DoS (Denial of Service ) attack is when a computer repeatedly sends requests to a server to overload the system . A server overload will slow the system and may take websites offline temporarily. A DDoS (Distributed Denial of Service ) attack is a coordinated attack using a botnet of infected systems to overload a server with requests . A botnet is a large group of devices controlled and used maliciously by an attacker. SQL Injection SQL ( Structured Query Language ) is a programming language used for manipulating data in databases . A SQL injection is when a malicious SQL query (command) is entered into a data input box on a website. If the website is insecure then the SQL query can trick the website into giving unauthorised access to the website’s database . An SQL injection can be used to view and edit the contents of a database or even gain administrator privileges . ' or 1 = 1 Brute Force Attack In order to break a password , every possible combination is tested in order from start to finish . This is not a quick method but it should break the password eventually and can be sped up if multiple computer systems are used at the same time. IP Address Spoofing An attacker changes the IP address of a legitimate host so any visitors to the URL are instead taken to a spoofed ( fake ) web page . This web page is used to record any inputted data (such as usernames and passwords) and send it back to the attacker . The spoofed web page can also be used to install malware . Q uesto's Q uestions 3.8 - Cyber Threats: 3.8a - Malware: 1. What is malware ? [ 2 ] 2a. Describe three characteristics of a virus . [3 ] 2b. Describe three characteristics of a worm . [3 ] 2c. What is a trojan ? [ 3 ] 2d. Describe how spyware and keyloggers work. [ 4 ] 2e. Explain how ransomware works and why it is difficult to trace attackers . [ 3 ] 2f. In your opinion, which malware do you think is the most dangerous and why ? [ 2 ] 3.8b - Data Theft: 1. Describe what is meant by ' phishing ' . [ 2 ] 2. Give an example of social engineering . [ 2 ] 3. What is interception ? What software is used to intercept data packets? [ 2 ] 4. Describe why systems and storage media should be disposed of securely . [ 1 ] 3.8c - Online Threats & Attacks: 1. Describe what is meant by ' hacking ' . [ 2 ] 2a. Describe what a DoS attack is and its impact . [2 ] 2b. Describe how a DDoS attack is different to a DoS attack . [2 ] 3. Describe what an SQL injection is and how an attacker would use it. [ 4 ] 4. Describe what is meant by a brute force attack . [ 2 ] 5. Describe IP address spoofing and its purpose . [ 3 ] 3.7 - The Internet Theory Topics 3.9 - Protection Against Threats

Learn about the differences between wired and wireless networks. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 3.2a: Wired & Wireless Networks Exam Board: OCR Specification: J277 Watch on YouTube : Wired Networks Wireless Networks Encryption Wired Connections Wireless Connections Wireless connections, such as WiFi or Bluetooth , use no cables but require a wireless network interface card (WNIC ). Wireless connections generally have a slower speed and can be affected by the computer's distance from the wireless router as well as obstacles like walls or bad weather. Wired connections use physical cables , such as copper or fibre optic wires , and require a network interface card (NIC ) to connect to a network. These wired connections use a wired connection protocol - most commonly Ethernet . Restricted Movement Faster More Secure NIC Required Freedom of Movement Slower Less Secure WNIC Required Encryption Wireless connections are less secure and require encryption . Encryption is the process of scrambling data into an unreadable format so that attackers cannot understand it if intercepted during transmission. The original data (known as plaintext ) is converted to scrambled ciphertext using an encryption key . Only at the correct destination will the encryption key be used to convert the ciphertext back into plaintext to be understood by the receiving computer. Q uesto's Q uestions 3.2a - Wired & Wireless Networks: 1. Briefly compare wired and wireless networks in terms of movement , transmission speed , security and required hardware . You could answer this in the form of a table. [ 8 ] 3.1b - Network Hardware & Internet Theory Topics 3.2b - Protocols & Layers

The list of topics in the 2020 OCR GCSE Computer Science specifications. OCR GCSE Computer Science (J277) These pages are based on the J277 OCR GCSE Computer Science specification . This website is in no way affiliated with OCR . Component One: Computer Systems OCR GCSE Key Term Generator Paper 1 Playlist on YouTube 1. Systems Architecture 1.1a - The CPU 1.1b - Registers & FE Cycle 1.2 - CPU Performance 1.3 - Embedded Systems 2. Memory & Storage 2.1 - Primary Storage 2.2 - Secondary Storage 2.3 - Units 2.4a - Number Systems 2.4b - Binary Addition & Shifts 2.4c - Character Storage 2.4d - Image Storage 2.4e - Sound Storage 2.5 - Compression 3. Networks 3.1a - Network Types & Performance 3.1b - Network Hardware & Internet 3.2a - Wired & Wireless networks 3.2b - Protocols & Layers 4. Network Security 4.1 - Network Threats 4.2 - Preventing Vulnerabilities 5. Systems Software 5.1 - Operating Systems 5.2 - Utility Software 6. Impacts 6.1a - Impacts of Technology 6.1b - Legislation Component Two: Computational Thinking, Algorithms and Programming Paper 2 Playlist on YouTube 1. Algorithms 1.1 - Computational Thinking 1.2 - Designing Algorithms 1.3 - Searching & Sorting Algorithms 2. Programming Fundamentals 2.1 - Programming Fundamentals 2.2 - Data Types 2.3 - Additional Programming Techniques 3. Producing Robust Programs 3.1 - Defensive Design 3.2 - Testing 4. Boolean Logic 4.1 - Boolean Logic 5. Languages & IDEs 5.1 - Languages & Translators 5.2 - Integrated Development Environment

Learn how to make simple calculations in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 3b - Simple Calculations Simple Calculations in Python You can perform calculations on numbers in Python using the four main operators : print ( 89 + 47) print ( 89 - 47) print ( 89 * 47) print ( 89 / 47) = 136 42 4183 1.8936170212765957 For addition , use the plus sign + To subtract numbers, use the dash symbol – (but not an underscore _ ) For multiplication , use an asterisk * which can be made by pressing Shift and 8 on a typical keyboard. To divide numbers, use a forward slash / (but not a backslash \ ) Use a string and the calculation to make the output user friendly . print ( "53 x 7 =" , 53 * 7) = 53 x 7 = 371 Simple Calculations Task 1 ( + - * /) Print four different simple calculations, using a different operator ( + - * / ) for each. Make the output user friendly by also showing the calculation (not just the answer). Copy the divide symbol here using Ctrl and C : ÷ Example solution: 18 + 35 = 53 18 - 35 = -17 18 x 35 = 630 18 ÷ 35 = 0.5142857142857142 Using Variables in Calculations You can also perform calculations on variables . The example below has the values of the variables pre-written. You need to store the result in a variable . The total variable has been used to store the result of the multiplication. num1 = 12 num2 = 20 total = num1 * num2 print ( "The total is" , total) = The total is 240 The example below allows the user to input values . num1 = int ( input ( "Enter number one: " )) num2 = int ( input ( "Enter number two: " )) total = num1 + num2 print ( "The to ta l is" , total) Enter number one: 21 Enter number two: 82 The total is 103 = Don't leave the user in the dark, better user interfaces are clear and explain what outputted values mean: num1 = int ( input ( "Enter number one: " )) num2 = int ( input ( "Enter number two: " )) answer = nu m1 - num2 print (num1 , "-" , n um2 , "=" , answer) Enter number one: 83 Enter number two: 29 83 - 29 = 54 = Simple Calculations Task 2 ( Divide by 3) Use an input line with int to ask the user to enter a number . Divide the number by 3 and output the result . Example solution: Enter a number: 11 11 divided by 3 is 3.6666666666666665 Simple Calculations Task 3 ( Add 3 Numbers ) Make three input lines using int to ask the user to enter three numbers . Add the numbers together and output the total . Example solution: Enter the first number: 45 Enter the second number: 32 Enter the third number: 19 The total is 96 ⬅ 3a - Data Types Section 3 Practice Tasks ➡

The homepage for all content aimed at Key Stage 3 students studying Computer Science / IT including computer hardware, Python, App Inventor 2 and Cyber Security. Key Stage 3 Topics These topics are aimed at Year 7 - 9 students (11 - 14 year olds) studying computing. Hardware The Motherboard The CPU Memory Expansion Cards Python Basics 1. The Basics 2. Variables 3. Inputs 4. Calculations 5. Selection 6. Turtle 7. Link to GCSE Python Cyber Security Malware Phishing & Staying Safe Other Topics Desktop Publishing