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Learn about lossy and lossless compression and the lossless compression algorithms run-length encoding and dictionary coding. This topic also covers symmetric and asymmetric encryption and the uses of hashing. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 3.1 - Compression, Encryption and Hashing Specification: Computer Science H446 Watch on YouTube : Lossy & Lossless Compression Lossless Compression Algorithms Encryption Hashing Lossy vs Lossless Compression Compression is the process of reducing the size of a file so it takes up less storage space and can be transmitted more quickly over a network . It works by encoding data more efficiently or removing unnecessary information . Benefits of compression include faster file transfer speeds , reduced storage requirements and improved performance when streaming data . Lossy compression permanently removes some data that is less important to human perception , such as subtle sounds or image details , resulting in smaller file sizes but slightly lower quality . Lossless compression reduces file size without losing any data , allowing the original file to be perfectly restored after it is decompressed . Lossless Compression Algorithms There are two types of lossless compression that you need to know: Run-Length Encoding (RLE ) is a simple form of lossless compression that reduces file size by storing repeating data as a single value and a count . For example, a sequence like AAAAABBBCCCC could be stored as A5B3C4 , saving space in files with many repeated elements , such as pixels in images . Dictionary Encoding replaces repeating patterns of data with shorter codes that reference entries in a dictionary . The dictionary stores common sequences once , and each repetition is replaced by a shorter reference , making it efficient for text and other data with recurring patterns . Encryption Encryption is the process of converting readable data (plaintext ) into an unreadable form (ciphertext ) to prevent unauthorised access . It ensures the confidentiality and security of information during storage or transmission . Symmetric encryption uses the same key for both encryption and decryption , meaning the sender and receiver must share the key securely . It is fast and efficient, but key distribution is a major risk if the key is intercepted . Asymmetric encryption uses a pair of keys - a public key for encryption and a private key for decryption . It is more secure for communication and vital for confidential uses such as banking . Hashing Hashing is the process of applying a mathematical function (hash function ) to data to produce a fixed-size value , known as a hash . It is a one-way process , meaning the original data cannot be reconstructed from the hash . Hashing is commonly used for data integrity checks , password storage and digital signatures . Even a tiny change in the input data produces a completely different hash , making it useful for detecting tampering or corruption . Q uesto's K ey T erms D id Y ou K now? Compression: lossy compression, lossless compression, run-length encoding, dictionary encoding Encryption: plaintext, ciphertext, key, symmetric encryption, asymmetric encryption Hashing: hash function, hash Alan Turing and his team used pattern recognition to analyse recurring sequences in encrypted German messages , helping to break the Enigma code , which was a major factor in the Allies’ victory in World War II . 2.4 - Programming Languages A-Level Topics 3.2 - Databases

Homepage for learning about computer science in school. Discover topics across GCSE and Level 3 IT subjects, plus programming languages including Python, HTML and Greenfoot. C omputer S cience Newb ie s Popular topics: Python Programming Application Development OCR Cambridge Advanced National in Computing (AAQ) A-Level Computer Science You are viewing the mobile version of CSNewbs. The site will appear better on a desktop or laptop . OCR A-Level (H446) GCSE Computer Science OCR GCSE (J277) Latest YouTube Video Latest Blog Post Links & Information YouTube Channel Last updated: Tuesday 10th February 2026 Millions of visits since 2017! About CSNewbs

Learn how to create variables in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 1c - Creating Variables What is a Variable? A variable represents a value that can change as a program is running . The two parts of a variable are the name (e.g. sweets) and the value (e.g. 8). sweets = 8 print (sweets) = 8 amount of sweets = 8 8sweets = 8 sweets A variable can't contain spaces , it must start with a letter , and you must declare its value before you can use or print it. You always need to print the variable name (e.g. biscuits), not the value (20) as the value can change. Important – When writing variable names, we do not need speech marks. (e.g. type biscuits , not “biscuits”) We use variables because the value of something might change as the program is executed. For example, if someone eats a sweet then the value of our variable changes: sweets = 8 print (sweets) sweets = 7 print (sweets) = 8 7 sweets = 8 print ( Sweets) You must be consistent with capital letters when writing variable names. sweets and Sweets are treated as two different variables. Creating Variables Task 1 ( Age & Pets) Make a variable named age and set it to your current age. On the next line print age . Make another variable named pets and set it to how many pets you have. On the next line print pets . Example solution: 14 2 Variables with Strings (Text) In programming, a collection of alphanumeric characters (letters, numbers and punctuation) is called a string . "Pikachu" is a string. In the example below, pokemon is the variable name that represents the variable value "Pikachu" . pokemon = "Pikachu" print (pokemon) = Pikachu To create a string, we use "speech marks" . Numbers by themselves and variable names do not use speech marks. Each variable can only have one value at a time, but it can change throughout the program. pokemon = "Pikachu" print (pokemon) pokemon = "Squirtle" print (pokemon) = Pikachu Squirtle Creating Variables Task 2 ( Superhero & Colour ) Make a variable named superhero and set it to any of your choice, such as "Spider-Man" . Print the superhero variable on the next line. Make another variable named colour and set it to the colour related to your chosen superhero. Print the colour variable on the next line. Example solutions: Spider-Man Red The Hulk Green ⬅ 1b - Co mmenting 1d - Using Variables ➡

Frequently asked questions about CSNewbs including content, the creator and contact. Frequently Asked Questions about Computer Science Newbies Who made CSNewbs? My name is Mr Pulsford . I am from London and I am currently the Head of C omputer Science at a secondary school in South Yorkshire , England . When and why did you make this? I wanted to make a resource that students could access outside of the classroom . I was working on a paid summer project at G o o g l e in London in 2016 when I was inspired to start the site. It went live in 2017 and I've been updating it single-handedly ever since , as much as I can outside of lessons and life. I made CSNewbs to support students in lessons and at home because Computer Science can be a tricky subject and many websites are too technical . Which courses does CSNewbs cover? The ' GCSE ' section follows the OCR J277 specification ( 2020 ) and Eduqas / WJEC specification ( 2020 ). The ' CTech ' section follows the OCR Cambridge Technicals Level 3 IT 2016 specification for Unit 1 (Fundamentals of IT) and Unit 2 (Global Information). The ' CANiC (AAQ) ' section follows the Cambridge Advanced Nationals in Computing specification for H029/H129 . It is in the process of being added. The ' Programming ' section contains material for Python , HTML , Greenfoot and others. The ' KS3 ' section covers basic Computer Science topics aimed at Year 7 - 9 students . Do the exam boards pay you money for this? CSNewbs is not affiliated with any exam board , financially or otherwise . The content on this site has been independently created by closely following the publicly released specifications by Eduqas and OCR. Can I get a level 9 / distinction just from CSNewbs? The content on this website is of high-quality and should be used to guide students towards a better understanding of the course's content. Like all resources however , it should be supported with a range of appropriate material and sound classroom teaching . CSNewbs makes no miraculous claims linking content use and final exam results. How did you make this website? CSNewbs.com was created and is maintained using Wix . What's the deal with copyright? CSNewbs is protected by copyright , and some copy / paste features have been disabled on the site. All images have either been created by myself or used from Wix's copyright-free vector gallery / their stock image library . Embedded videos are linked to content from the CSNewbs YouTube page. If you think any content on this site infringes a copyright-protected work , please email me, and I will make immediate changes . I don't see any adverts, how are you making money? You're right, there are no adverts and I intend to keep it that way. I don't make and never have made any money from this website. Can you add Unit 3 / OCR A-Level / something else? The site continues to expand over time with new content . The eventual aim is to cover every exam board for GCSE Computer Science but that will take a lot of time! How come something on the site isn't working at my school? Your school's IT administrators may have blocked some elements such as JavaScript or embedded YouTube videos . The videos can be watched directly on YouTube (if not blocked on your school network). Who is the robot? The robot is called Questo . It's the site mascot and it appears on most pages to ask you questions about the content (' Questo's Questions '). It used to have a body but since 2020 it's just a head. I can't believe one person made this whole site while teaching and the rest, what are your long-term plans? If you work for an exam board or educational resource organisation , and your organisation has opportunities available , please send me an email. How can I contact the creator of CSNewbs? The contact email is: Privacy Policy There are social media pages for CSNewbs but, aside from YouTube , they are rarely updated .

Learn about the two types of data storage unit systems and how the increments work, including kilobyte and kibibyte. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.7 - Units of Measurement Exam Board: OCR Specification: 2016 - Unit 1 All computer systems communicate , process and store data using binary because this is the format that the processor understands . Binary is a number system consisting entirely of 0s and 1s . A single binary data value (a 0 or a 1 ) is called a bit . 4 bits is called a nibble (e.g. 0101 or 1100). 8 bits is called a byte (e.g. 10101001 or 01011100). There are two main measurement systems : Metric Units of Measurement The gap between units when using metric values (also known as the decimal system ) is always 1,000 . For example, there are 1,000 bytes in 1 kilobyte and 1,000 kilobytes in 1 megabyte . To convert between metric units , divide by 1,000 when moving to a larger unit (e.g. 500 megabytes is 0.5 gigabytes ) and multiply by 1,000 when moving to a smaller unit (e.g. 4.7 terabytes is 4,700 gigabytes ). For example, 8,520 KB is the same as 8.52 MB or 0.00825 GB . Metric values (usually) have a prefix ending in ‘ a ’ such as mega byte or giga byte. Binary Units of Measurement The gap between units when using binary values is always 1,024 . For example, there are 1,024 bytes in 1 kibibyte and 1,024 kibibytes in 1 mebibyte . To convert between binary units , divide by 1,024 when moving to a larger unit (e.g. 4,096 kibibytes is 4 mebibytes ) and multiply by 1,024 when moving to a smaller unit (e.g. 55 pebibytes is 55,296 tebibytes ). For example, 34 KiB is the same as 34,816 MiB or 35,651,584 GiB . Bi nary values have a prefix ending in ‘ bi ’ , such as ki bi byte or me bi byte. Computer scientists often use the binary system of measurement because the storage size is technically more accurate . Q uesto's Q uestions 1.7 - Units of Measurement: 1 a. Create a table or list that clearly shows the relationship between values from bit up to petabyte for the metric (decimal) measurement system . [4 ] 1 b. Create another table to display the binary measurement system from bit to pebibyte . [4 ] 2. Make the following conversions and show your working out . [2 each ] a. 40 megabytes into kilobytes . b. 8500 gigabytes into terabytes . c. 100 mebibytes into kibibytes . d. 854,016 mebibytes into gibibytes . e. How many bytes are there in 3 megabytes ? f. How many bytes are there in 3 mebibytes ? 1.6 - Hardware Troubleshooting 1.8 & 1.9 - Number Systems Topic List

Learn about the differences and characteristics of programs and applications. Resources based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced Nationals 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) 1.1 - Programs & Applications Watch on YouTube : Programs & Applications The terms 'program ' and 'application ' do not mean the same thing. A program performs individual operations while an application may use several programs together to create a functional tool for a user . For example, a program may calculate the total of a range of numbers . An example of an application is Microsoft Excel , which is spreadsheet software with a range of programs built in , including the ability to calculate totals , as well as many other functions . Programs and Applications Every topic in Unit F160 ( Fundamentals of Application Development ) comes with YouTube videos to help you learn . Some pages only have one video , while others have several . Programs Applications A program is a set of instructions that a computer can understand and execute to perform specific tasks . It is written in a programming language like Python or Java and instructs the computer how to perform individual operations . Programs can be simple (e.g. printing a message to the screen) or complex (e.g. managing a database or running a web server ). An application is a type of program designed to be user-friendly and help users complete specific tasks . Examples of applications include word processors (e.g. Microsoft Word), web browsers (e.g. Google Chrome) and mobile apps (e.g. Instagram). Applications are made up of one or more programs . Examples A program has a specific purpose , that is understood and executed by the computer . An example is a program that can sort data into alphabetical order . This may be used in an application like spreadsheet software . A video editing application may include several programs , each with a specific purpose , such as a program to import video , one to apply filters , another to edit audio and another to export the finished video . Characteristics Characteristics of a program: Programs are created using programming languages like Python or Java . They are translated into a format the computer understands and then run . Each program is designed to perform a specific function or set of functions . They may not have a user interface and may not require user interaction , such as an operating system's background processes . Programs may consist of smaller sub-programs that can be reused in different applications . Characteristics of an application: Applications are designed to meet user requirements . They are designed for specific tasks , such as editing photos or sending emails. Most have a user interface to provide a way for humans to interact with the application, e.g. menus and buttons . Applications may be designed to run on specific operating systems , such as an iPhone app designed for iOS. They may involve multiple programs working together . Devices that use Programs and Applications Every type of computer system will use programs and/or applications for different, specific purposes . Desktops and laptops run operating systems , software applications and utilities . Game consoles use applications for gaming , streaming and social features like group voice chats. Smart TVs use apps for streaming and browsing and programs for remote control . Smart speakers use programs to process voice commands , control smart home devices and play music based on user input . Smartphones and tablets use mobile apps for communication , games and productivity . AR (augmented reality ), VR (virtual reality ) and MR (mixed reality ) devices use programs to generate and manage 3D environments , track user movements and respond to inputs . Embedded systems like washing machines , smart fridges and cars use programs to manage their operations and interfaces . Q uesto's Q uestions 1.1 - Programs & Applications: 1. Explain the differences between a program and an application , using examples . [4 ] 2. Give 3 characteristics of a program and 3 features of an application . [6 ] 3. Briefly summarise how four different devices would use programs or applications . [4 ] As of 2025 , the Google Play Store has over 3.5 million apps and is close to reaching 150 billion downloads ! D id Y ou K now? Topic List 1.2 - Operating Systems

Learn about the denary, binary and hexadecimal number systems and how to convert between them. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.8 & 1.9 - Number Systems & Conversion Exam Board: OCR Specification: 2016 - Unit 1 What is binary? 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 . How to convert from binary to denary: How to convert from denary to binary: 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 is 9EB. Hexadecimal only uses single-character values. Double-digit numbers are converted into letters - use the table on the right to help you understand. How to convert from binary to hexadecimal: How to convert from hexadecimal to binary: Converting from denary to hexadecimal / hexadecimal to denary To convert from denary to hexadecimal or the other way round you must convert to binary first . Denary > Binary > Hexadecimal Hexadecimal > Binary > Denary Use the videos on this page if you need help converting to or from binary. The most common number systems question in exams are from denary to hexadecimal or from hexadecimal to denary so make sure that you practice these conversions. Q uesto's Q uestions 1.8 & 1.9 - Number Systems: 1. Explain why hexadecimal numbers are used as an alternative to binary . [ 2 ] 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 ] Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube By now you should know that computer systems process data and communicate entirely in binary . Section 1.7 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 . Click the banners above to try self-marking quizzes (Google Form) on these topics. Denary to Binary: Binary to Denary: Binary to Hexadecimal: Hexadecimal to Binary: 1.7 - Units of Measurement Topic List 2.1 Software Types

Learn how to use App Inventor 2 to create simple programs. Try to complete task 3 on this page. Perfect for Key Stage 3 students to experiment with block coding, objects and properties. App Inventor Task 3 - Munchin' Pizza This page will teach you how to make a simple app that changes pictures when a button is pressed . You can make the app more complex by adding sounds or additional buttons. Step 1: Set up App Inventor 2 Open App Inventor 2 (use the button on the right) and create a new project. You will need to log in with a Google account. Download the picture images from the zipped folder on the App Inventor 2 Basics page here . Once you have downloaded the pizza pictures you will need to upload them. Find the Media tab on the right side of App Inventor and click 'Upload File...' You will need to upload each picture individually. In the Palette tab on the left side, drag two buttons into the middle screen so they look like this: In the Components tab on the right, click on Button1 and click the Rename button at the bottom to change it to Pizza . Then Rename Button2 to Munch . This will help us when we code later as it will be less confusing. Click on the second button (Munch) that you just dragged into the centre then look in the Properties tab on the right and scroll down to Text . Change 'Text for Munch' to something like 'Munch Pizza' . Now click on the first button in the centre (Pizza) and in the Properties tab, click on Image and select the first image. It should be the full slice of pizza. When you have set the image, you might notice it goes a bit crazy. Still in the Properties tab, change the Height and Width to 'Fill parent...' for both. This will make the image fit within the boundaries of the screen. Finally, change the Text for the Pizza button to be blank. Otherwise it will appear on top of the pizza and look odd. So far you should have a button disguised as a pizza and another button that tells you to munch that lovely cheesy deliciousness. If your program does not look like this, read the instructions above again carefully. Step 2: Code Click on the Blocks button in the top right to start adding code. In the Blocks tab on the left side click on Munch and drag the when Munch Click block into the centre. This block will execute any code inside of it whenever the munch button is clicked. In the Blocks tab on the left side click on Logic and drag an if then block and snap it inside the block you just dragged over. Click on the blue cog button and drag four else if blocks inside the if block at the bottom. The blocks at the top will automatically update when you drag the blocks under the if block underneath. Because we are using different images, we need to check which image is currently being displayed, so we know which picture to change to. Firstly we want to check if the first image is being displayed. Connect an = block from the Logic section. Then add a Pizza Image block from the Pizza section. Lastly grab a " " block from the Text section and write the name of your first image inside (e.g. pizza1.jpg) Don't forget the extension (.jpg). But what does this code actually mean? It is checking to see what the current pizza image is. And if it is pizza1.jpg then it is going to... ...change the picture to pizza2.jpg, as if someone has munched the pizza! Grab a set Pizza Image to block from Pizza and then snap another " " block from Text and add the pizza2.jpg text inside. Now that we have written the code to check the current picture and move it to the next one when pressed, we just need to copy this for the other four pizza pictures. Rather than select all the blocks again, right-clicking on the blocks and selecting 'Duplicate' will copy them. Copy each block and then change the values so that if pizza2.jpg is the current image, then it sets it to pizza3.jpg and so on. Make sure that pizza5.jpg sets the image to pizza1.jpg so that it goes round in a loop. Program 3 Complete! Step 3: Run The easiest way to run an app that you have created at home using App Inventor 2 is to download the free MIT AI2 Companion App on your smartphone from the Google Play Store . At the top of the App inventor program on your computer , click on Connect and AI Companion . This will generate a six-digit code you can type into your phone. If your school has the emulator installed, you can also use this to test your app. Extra Step: Challenges 1. Create your own images and upload them . You can easily create your own set of pictures and link them together. Why not try: Eating a different type of food (e.g. cookie or doughnut). A simple scene that changes from night to day. A simple character that changes appearance (like Pikachu powering up a thunder strike with each button press). 2. Add a sound effect whenever a button is pressed . In the video at the top of the page, you'll see I have a 'munch' sound whenever the button is pressed. You could record this sound yourself or use a sound effect site. Once you have got your sound file (it should be short and .mp3) you need to upload it, just like you uploaded your images. In the Designer layout click 'Upload file...' in the Media tab on the right. Then look in the Palette tab on the left side, open the Media section and drag a Sound block into the centre. It will appear underneath the phone screen in a section called 'non-visible components' which is fine. Now click on Properties on the right side and choose the sound file you just uploaded in the Source box. Click on the Blocks button in the top right to start adding the code! In the Blocks tab on the left side, click on Sound1 and drag the call Sound1 Play block directly underneath when Munch click . This will play the sound everytime the button is pressed. 3. Add more buttons . You could add a second clickable button which reverses the pattern and a third button that resets the order back to the first image. Adding new buttons is easy - drag them from the Palette tab in the Designer layout. Change the button text in the Properties tab and the name of the button in the Components tab. To add code, click on Blocks in the top right then you can duplicate the code for Munch by right-clicking and choosing Duplicate. Now just change the values to what you want. If you are making a reset button, you don't need an if then statement, just set the image to your first image when the button is clicked. Keep messing around with the program and have fun! KS3 Home Tasks 4, 5 & 6

Learn about the laws related to computing - the Data Protection Act, Computer Misuse Act, Copyright Design and Patents Act and Regulation of Investigatory Powers Act. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level Specification: Computer Science H446 5.1 - Computing-related Legislation Watch on YouTube : Data Protection Act Computer Misuse Act Copyright Design and Patents Act Regulation of Investigatory Powers Act Several key UK laws govern the ethical and legal use of computers and digital information including the Data Protection Act and Computer Misuse Act . Each act is designed to protect data , users or intellectual property in the digital age. Data Protection Act (2018) The Data Protection Act is a UK law designed to ensure that personal data is collected , stored and used responsibly . It gives individuals (data subjects ) rights over their personal information and sets rules for organisations that process it . Introduced in 1998 , it was updated in 2018 to align with the EU’s General Data Protection Regulation (GDPR ). The Data Protection Act's key principles include that data must be processed lawfully , fairly and transparently , used for specific purposes , kept accurate and up to date , stored securely and not kept longer than necessary . It also gives data subjects rights such as accessing their data , correcting inaccuracies , objecting to processing and requesting deletion . Organisations that break the law can face heavy fines and legal action from the Information Commissioner’s Office (ICO ). YouTube video uploading soon Computer Misuse Act (1990) The Computer Misuse Act (1990 ) is a UK law created to make unauthorised access and use of computer systems illegal . It was introduced in response to the rise of hacking and other cybercrimes as computers became more common . This act defines several offences , including: Unauthorised access to computer material , such as hacking into a system without permission . Unauthorised access with the intent to commit further offences , such as fraud or data theft . Unauthorised modification of data or programs , for example, spreading viruses or deleting files . Making , supplying or obtaining tools used for committing these offences . Penalties range from fines to imprisonment , depending on the severity of the crime . This act helps protect individuals , organisations and data from malicious attacks and misuse . YouTube video uploading soon Copyright, Designs & Patents Act (1988) The Copyright, Designs and Patents Act (1988 ) is a UK law that protects people’s creative and intellectual work from being copied or used without permission . It gives creators automatic legal rights over their original work , such as books , music , films and software . The act states that the copyright owner controls how their work is used , including the rights to copy , distribute or adapt it. Anyone wishing to use the work must get permission or a licence from the owner. It also includes exceptions , allowing limited use for purposes like education or research . This act helps ensure that creators are fairly rewarded for their work and that their intellectual property is legally protected . YouTube video uploading soon Regulation of Investigatory Powers Act (2000) The Regulation of Investigatory Powers Act (RIPA ) (2000 ) is a UK law that governs how public bodies and law enforcement can carry out surveillance and access electronic communications . It was introduced to balance national security and crime prevention with individuals’ right to privacy . RIPA allows authorised agencies , such as the police , intelligence services and local councils , to monitor communications , intercept phone calls or emails and use covert surveillance , but only with proper legal authorisation . It also regulates the use of informants and access to encrypted data . This act aims to ensure that surveillance is done lawfully , proportionately and for legitimate purposes , such as preventing or detecting serious crime or protecting public safety . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Legislation: Data Protection Act (2018) Computer Misuse Act (1990) Copyright Design and Patents Act (1988) Regulation of Investigatory Powers Act (2000) D id Y ou K now? In 1985 , two journalists were arrested for ‘ hacking ’ into the emails of the Duke of Edinburgh ( Prince Philip ) after discovering an engineer’s username was ‘ 2222222222 ’ and password was ‘ 1234 ’. They were acquitted in court because no UK laws covered hacking , exposing a major legal gap that led to the creation of the Computer Misuse Act ( 1990 ) . 4.3 - Boolean Algebra A-Level Topics 5.2 - Moral & Ethical Issues

A tutorial to understand how to create a game in Greenfoot. A simple step-by-step guide and walkthrough featuring all code needed for the Eduqas GCSE 2016 specification. Installing Greenfoot Greenfoot Home According to the Eduqas 2016 specification exam students will use version 2.4.2 of Greenfoot in the Component 2 exam . Eduqas GCSE students should practice using version 2.4.2 - despite the most up-to-date version currently being 3.6.1. If you are not learning Greenfoot for the Eduqas GCSE then you may wish to download and use the most current version. Eduqas 2016 Specification Students Other Students The version used in the Component 2 exam is 'Greenfoot version 2.4.2 '. Scroll down to 2.4.2 on the old download page and select the correct version for your computer. Windows systems should use the 'For Windows ' option. If you are not following the Eduqas 2016 specification then you should download the most up-to-date version of Greenfoot. Select the correct version for your computer at the top of the download page .

Learn how to use App Inventor 2 to create simple programs. Try to complete the final task (7) on this page. Perfect for Key Stage 3 students to experiment with block coding, objects and properties. App Inventor Task 7 - Pop-up Blob The previous apps have been preparing you to make a longer and more complicated app. Now we will put together all of the skills you have learned to create a fun game. Check the video: Open App Inventor 2 (use the button below) and create a new project. You will need to log in with a Google account. App Inventor 2 Ready for a challenge? This is what the program looks like in Designer layout. To the left are the components with all their Properties correct. To the right are the Components names. Put the three labels and button inside a HorizontalArrangement from the Layout section of Palette . The Text for ScoreLabel is 'Score: 0'. The Text for TimeRemainingLabel is 'Time Remaining:'. The Text for SecondsLabel is '20'. Place an ImageSprite inside a Canvas (both from the Drawing and Animation section of Palette ). Download the blob image from the Basics page here and upload it as the Picture for the ImageSprite . Change to Blocks layout and drag a initialize global to block from Variables . Type 'Score' in the empty space to create a variable that we will use to track how many times the blob has been touched. Attach a 0 block from Math to start the score at 0. This big block of code uses some of the concepts which you have used before. Whenever the Blob is touched the variable Score is increased by 1. The X and Y coordinates of the Blob are changed by random numbers so it will appear in a random location on the screen. The bottom blocks change the ScoreLabel to show the current score. Every second that the timer ticks we want to check if the score is more than 1 (to check it hasn't reached 0). If it is more than 1 second then the time will count down by 1. In the else part you need to add the following: Set Blob Enabled to false . Set Blob Visible both to false . Set TimeRemainingLabel Visible to false . Set SecondsLabel Visible to false . When the Reset Button is clicked the score variable is changed to 0 and the Seconds label is rewritten to 0. Make sure you use the " " block from Text and not a block from Math. Inside the when ResetButton Click block you need to reverse the code you have added for the else block when the timer ticks: Set Blob Enabled to true . Set Blob Visible both to true . Set TimeRemainingLabel Visible to true . Set SecondsLabel Visible to true . Extra Step: Challenges 1. Large score display . If you watch the video at the top of the page again, you will see that when the time runs out (is less than 1) some of the labels turn invisible and the TextColour and FontSize of the ScoreLabel changes. Try to do the same in your app. Remember to reverse what you have done in the code for the reset button; otherwise, the labels will still be invisible! 2. Customise your game . Change the background of the Canvas to an image, change the blob to a different image and add a sound when the character is 'popped'. 3. *HARDER Challenge* Add a High Score Label . Follow these hints carefully and use the colours to help you. You need to initialize a new Variable called HighScore and set it to 0 . You also need to add a new HighScoreLabel and put it in your Horizontal Arrangement in Designer layout. Add an if then block in the else part of the When Timer Timer block you already have. If Score > HighScore then HighScore = Score . This will change the value of HighScore to the current Score if it is higher than the current high score. Remember to make the HighScoreLabel display the new HighScore . KS3 Home

Learn about designs, documents and diagrams related to human-computer interaction including processing and data handling, data flow diagrams (level 0 and level 1), flowcharts and user interface designs (visualisation and wireframe diagrams). 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) 5.3 - Human Computer Interface Designs, Documents and Diagrams Watch on YouTube : Data flow diagrams Flowcharts Visualisation diagrams Wireframe diagrams There are four types of documents / diagrams you need to know that can be used to design human-computer interfaces : data flow diagrams (DFDs ), flowcharts , visualisation diagrams and wireframe designs . For each type of diagram , you need to know its components and conventions , when it is appropriate for use , and how to create it . Each diagram is also effective for different uses and you must be able to consider how specific diagrams can be made more effective . Human-Computer Interface Diagrams Data Flow Diagrams A data flow diagram (DFD ) is a visual representation of how data is transferred within a system or organisation . They do not show decision logic or sequencing , but focus on where data comes from , where it goes and how it is processed . DFDs are typically categorised into Level 0 and Level 1 formats, which differ based on complexity . Flowcharts A flowchart is a diagram that shows the sequence of steps in a process using specific symbols . Flowcharts can be used as a project planning tool (section 3.2 ) to visualise workflows , task order and decision-making paths . It is also useful as a human-computer interface diagram to show the steps and decisions users may take as they interact with the application . The video says ' 3.2d ' because flowcharts also appear in section 3.2 as a project planning tool . Visualisation Diagrams Visualisation diagrams are graphical representations used to show the layout , structure and appearance of a software application's interface . They're often used for planning , design and feedback purposes. Traditionally, they would be drawn on paper in pencil and annotated , but modern diagrams are mocked up on a computer so they can be easily shared with team members and clients . Wireframe Diagrams Wireframe diagrams are basic visual guides used to represent the structure and layout of a user interface (UI ) without any design styling . They focus on function , layout and interaction , not aesthetics . Wireframe diagrams are used in the early design stages to plan the UI layout before visual design begins. Q uesto's Q uestions 5.3 - Human Computer Interface Designs, Documents & Diagrams: 1. Explain what the purpose of data flow diagrams are, the difference between Level 0 and Level 1 and what makes them effective . [6 ] 2. Draw a wireframe diagram for the YouTube homepage . [3 ] 3. Explain how visualisation diagrams are created and how they can be made more effective . [ 5 ] The first type of flowchart , the ' flow process chart ', was developed by engineers Frank and Lillian Gilbreth in 1921 . The book (and original movie ) ' Cheaper by the Dozen ' is about this couple . D id Y ou K now? 5.2 - Visual Design Considerations Topic List 6.1 - Job Roles