Learn about the different data types used in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 3a - Data Types Data Types in Python If you are a Computer Science student you need to know about the different data types that are used in programming. String – A sequence of alphanumeric characters (e.g. “Hello!” or “Toy Story 4” or “Boeing 747” ) Integer – A whole number (e.g. 1470 or 0 or -34) Float (also called Real ) – A decimal number (e.g. -32.12 or 3.14) Boolean – A logical operation (True or False) Character – A single alphanumeric character (e.g. “a” or “6” or “?”) [ Not used in Python as it would just be a string with a length of 1] Converting to Another Data Type Converting a variable from one data type to another is called casting . Casting Commands str (variable_name) converts a variable to a string . int (variable_name) converts a variable to a integer . float (variable_name) converts a variable to a float (decimal number). An integer (or float ) value may be cast into a string so that it can be used with + as part of a sentence to avoid spaces . total = 45 print ( "You owe £" , total , "in total." ) print ( "You owe £" + str (total) , "in total." ) = You owe £ 45 in total. You owe £45 in total. When dividing an integer the answer is automatically given as a decimal number (float ), even if it is .0 (e.g. 10 / 2 would give 5.0). Casting a float (also known as real) number into an integer using int() will remove the decimal . total = 100/10 print ( "The answer is" , total ) print ( "The answer is" , int(total) ) The answer is 10.0 The answer is 10 = Data Types Task 1 ( Time) Write an input line with int to ask the current hour . Write another input line with int to ask the current minute . Write a print line with str() that outputs this as a clock time. Example solution: What is the hour? 12 What is the minute? 44 The time is 12:44 Data Types Task 2 ( Decimal ) Write an input line with int to ask for any number . Use float() in a print line to output number as a decimal. Example solution: Enter any number: 456 456.0 ⬅ Section 2 Practice Tasks 3b - Simple Calculations ➡

Learn about key computing laws including the Data Protection Act (2018), Computer Misuse Act (1990), Copyright, Designs and Patents Act (1988) and software licences. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). Exam Board: OCR 6.1b: Legislation Specification: J277 Watch on YouTube : Data Protection Act Computer Misuse Act Copyright, Designs & Patents Act Open Source Licence Proprietary Licence Data Protection Act (2018) In 2018 the European Union introduced GDPR (General Data Protection Regulation ) to protect the privacy of data for people in the EU. The UK matched this by updating the Data Protection Act introduced in 1998 to become the Data Protection Act (2018) . This act protects the data of individuals that is stored on computers and processed by organisations. How the Data Protection Act works: Each person who has their data stored is known as a data subject . An employee within an organisation must be appointed as a data controller and it is they who are responsible for registering with the Information Commissioner . The Information Commissioner is the person in the UK who is responsible for managing several laws , most significantly the Data Protection Act. When registering with the Information Commissioner, the organisation's data controller must be clear on exactly: What information they are collecting, Why it is being collected, What the data will be used for . The six principles of the Data Protection Act state that data must be: 1. Collected lawfully and processed fairly. 4. Data must be accurate and up-to-date. 2. Only used for the reasons specified. Principles of the Data Protection Act (2018) 5. Data must not be stored for longer than necessary, 3. Data must be relevant and not excessive. 6. Data must be stored and processed securely. Computer Misuse Act (1990) This act was introduced as computers became cheaper and more common at home and work . The act attempts to stop and punish those who use computers inappropriately . Breaking any of the three principles could result in fines and a jail sentence but only if it can be proved it was done on purpose and not by accident. The Computer Misuse Act (1990 ) includes three main principles : 1. No unauthorised access to data. Example: Hacking a computer system. 2. No unauthorised access to data that could be used for further illegal activities. Example: Accessing personal data to use as blackmail or identity theft. 3. No unauthorised modification of data. Example: Spreading a virus to change data. Copyright, Designs & Patents Act (1988) This act makes it a criminal offence to copy work that is not your own without the permission of the creator or the copyright holder. This can refer to text, images, music, videos or software. Owning the copyright of an image might not prevent others from copying and using it but this act means that the owner can bring legal proceedings in court to those who have stolen their work . However, it is difficult to trace who has stolen work once it has been uploaded to the internet and copies can easily spread, especially television shows and movies. This act specifically prohibits the following actions: Making copies of copyrighted material to sell to others . Importing and downloading illegally copied material (except for personal use). Distributing enough copyrighted material to have a noticeable effect on the copyright holder . Possessing equipment used to copy copyrighted material , as part of a business. Software Licences A software licence refers to how a user can legally use the software , there are two main types: Open Source Licence Source code is the software code written by programmers . If the software is open source it means that users can view and modify the source code . Linux, Python and Firefox are examples of open source software. Benefits Drawbacks Because the source code is available to edit , it can be customised to the organisation's needs . Often shared in the public domain so users can work together to modify, debug and improve a product. Unwanted features can be removed to make the software run faster . There are security risks - some editors may add malicious code to the program. Open source software is often low in price and sometimes free. It may be difficult to receive support as development is often distributed between people in different locations. The code may be prone to errors as it may not have been tested fully. It requires technical skills to be able to adapt source code efficiently and to maintain the code . Proprietary Licence Another term for a proprietary licence is closed source because the code is restricted - users are prevented from being able to view or modify the source code . You buy the right to use the software but you don't actually own it. Microsoft Office, Fortnite and Spotify are examples of closed source software. Benefits Drawbacks The code is well tested and has been professionally developed. Updates will generally be secure . Users must rely on the company to provide updates and fix issues. This might be infrequent or stop completely. The company can be held to account if it does not perform as listed in the terms and conditions upon purchase. Often not free and may be expensive. Most developers will provide some form of help/support . Users cannot modify, debug or improve the code for their own benefit. Q uesto's Q uestions 6.1b - Legislation: 1a. State the 6 principles of the Data Protection Act (2018) . [ 6 ] 1b. Explain how the Data Protection Act works . In your answer, you should include definitions of a data subject , the data controller and the Data Commissioner . [ 6 ] 2. Describe the 3 principles of the Computer Misuse Act (1990) . [3 ] 3a. What is the purpose of the Copyright, Designs & Patents Act (1988) ? [ 2 ] 3b. Describe 3 actions that CDPA (1988) prohibits . [ 3 ] 4a. Describe the difference between an open source and a proprietary licence . [ 2 ] 4b. State two benefits and two drawbacks of using software with a: Open source licence [ 4 ] Proprietary licence [ 4 ] 6.1a - Impacts of Technology Theory Topics

Learn about network devices such as a switch, router, modem and NIC. Also learn about internet terms and services including DNS and the Cloud. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 3.1b: Network Hardware + The Internet Exam Board: OCR Specification: J277 Watch on YouTube : The Internet Network Hardware DNS Servers The Cloud Network Devices When sending data across a network, files are broken down into smaller parts called data packets . Whole files are too large to transfer as one unit so data packets allow data to be transferred across a network quickly . Each packet of data is redirected by routers across networks until it arrives at its destination. Data packets may split up and use alternative routes to reach the destination address. When all the packets have arrived at the destination address the data is reassembled back into the original file. Wireless Access Point A Wireless Access Point provides a link between wireless and wired networks . It creates a wireless local area network that allows WiFi-enabled devices to connect to a wired network. Examples of a wireless access point in a public space could be a WiFi or Bluetooth hotspot , for example a WiFi hotspot in a coffee shop or airport to provide access to the internet. A wireless access point may be a separate device or built into another device such as a router. Router Routers are used to transfer data packets between networks . Routers receive data packets and use the IP address in the packet header to determine the best route to transmit the data. Data is transferred from router to router across the internet towards the destination. A router stores the IP address of each computer connected to it on the network and uses a list called a routing table to calculate the quickest and shortest route to transfer data. Switch A switch is used to connect devices together on a LAN . It receives data packets from a connected node, reads the destination address in the packet header and forwards the data directly to its destination. A switch will generate a list of the MAC addresses of all devices connected to it when it receives data , and must scan for a matching destination address before sending. An alternative to a switch is a hub but a hub is slower and less secure as it forwards a copy of received data to all connected nodes . Network Interface Controller / Card A Network Interface Controller (NIC ) commonly also known as a Network Interface Card is an internal piece of hardware that is required for the computer to connect to a network . The card includes a MAC address which is used when sending data across a LAN . An ethernet cable is plugged into the network card to allow data to be exchanged between the device and a network. A NIC used to be a separate expansion card but is now typically embedded on the motherboar d . Transmission Media Although not technically a device, the communication channel along which data is transferred will affect performance . Three common types of transmission media include: Ethernet cables - used typically on a LAN to transfer data between nodes and hardware such as switches. Examples include Cat5e and Cat6. Fibre Optic cables - very fast but more expensive and fragile cables typically used to send data quickly along a WAN . Data is sent as pulses of light . Coaxial cables - older , slower , copper cables that are not used as much in modern times as they can be affected by electromagnetic interference . The Internet The internet is a global network of interconnected networks . The world wide web (WWW ) is not the same as the internet. It is a way of accessing information , using protocols such as HTTPS to view web pages . Servers provide services on the internet , such as a web server which responds to the web browser (client) request to display a web page . The web server processes the client request to prepare the web page and return it so the web browser can display it to the user . A website must be hosted (stored) on a web server so that it can be accessed by others using the internet . A unique domain name (e.g. csnewbs.com) must be registered with a domain registrar – this is a company that checks the name is valid and not already taken . What is the Internet? DNS Servers A DNS ( Domain Name System ) server stores a list of domain names and a list of corresponding IP addresses where the website is stored. The first thing to understand is that every web page has a domain name that is easy for humans to remember and type in (such as www.csnewbs.com ) as well as a related IP address (such as 65.14.202.32) which is a unique address for the device that the web page is stored on. The steps taken to display a web page: 1. A domain name is typed into the address bar of a browser . 2. A query is sent to the local DNS server for the corresponding IP address of the domain name . www.facebook.com 3. The local DNS server will check if it holds an IP address corresponding to that domain name. If it does it passes the IP address to your browser . 66.220.144.0 4. The browser then connects to the IP address of the server and accesses the web site . If the local DNS server does not hold the IP address then the query is passed to another DNS server at a higher level until the IP address is resolved. If the IP address is found, the address is passed on to DNS servers lower in the hierarchy until it is passed to your local DNS server and then to your browser. Cloud Storage The cloud refers to networks of servers accessed on the internet . Cloud computing is an example of remote service provision . Cloud servers can have different purposes such as running applications , remote processing and storing data . When you store data in 'the cloud', using services such as Google Drive or Dropbox, your data is stored on large servers owned by the hosting company . The hosting company (such as Google) is responsible for keeping the servers running and making your data accessible on the internet . Cloud storage is very convenient as it allows people to work on a file at the same time and it can be accessed from different devices. However, if the internet connection fails , or the servers are attacked then the data could become inaccessible . Cloud Storage Characteristics: ✓ - Huge CAPACITY and you can upgrade your subscription if you need more storage. ✓ / X - Cloud storage is difficult to rank in terms of PORTABILITY , DURABILITY and ACCESS SPEED because it depends on your internet connection. A fast connection would mean that cloud storage is very portable (can be accessed on a smartphone or tablet) but a poor connection would make access difficult . ✓ - Cloud storage is typically free for a certain amount of storage. Users can then buy a subscription to cover their needs - Dropbox allows 2 GB for free or 2 TB for £9.99 a month. Q uesto's Q uestions 3.1b - Network Hardware & Internet: 1a. Explain how a switch works. [ 2 ] 1b. Describe the purpose of a router . [ 2 ] 1c. State what WAP stands for and why it is used . [ 2 ] 1d. State what NIC stands for and why it is required . [ 2 ] 1e. State the differences between the three main types of transmission media . [ 3 ] 2a. State what the internet is and how it is different to the world wide web . [ 2 ] 2b. What is web hosting ? [ 2 ] 3a. What is a DNS server ? [ 2 ] 3b. Describe, using a mix of text and icons / images , how a DNS server is used to display a web page . [5 ] 3c. Describe how a DNS server searches for an IP address if it is not found on the local DNS server . [ 2 ] 4a. Describe what cloud computing is. [ 2 ] 4b. State two advantages and two disadvantages of the cloud . [ 4 ] 3.1a - Network Types & Performance Theory Topics 3.2a - Wired & Wireless Networks

Learn about six different types of computer system including embedded, mainframe and quantum. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.3 - Computer System Types Exam Board: OCR Specification: 2016 - Unit 1 Different types of computer system are available to purchase and use, each with their own benefits , drawbacks and typical functions . Desktop A computer suitable for use at an ordinary desk. They are bulky and not so easy to move . Individual components (e.g. graphics card) can be upgraded over time . Desktops are versatile , they allow the user to carry out a range of activities , including document creation, data manipulation, game playing, design and communication facilities for personal or business purposes. Tablet / Laptop A small and portable type of computer. Many modern laptops can also fold back , effectively turning them into a tablet with a screen-based virtual keyboard . They can perform many of the functions of the traditional PC, but the screen size can be restrictive , especially if several documents need to be open at the same time. Because it can be transported through public spaces, loss or theft is more likely. Smartphone Embedded Systems Smartphones can be used to run a range of applications including email, social media, videos and music. However, they can negatively affect social interaction (e.g. by using them and ignoring people around you) and reduce spatial awareness when being used. Security is another issue as they can be easily lost or stolen . Security software for phones is not as secure as other computer systems so sensitive data should not be held on smartphones. An embedded system is when a smaller computer system is installed within a larger device , such as a washing machine, traffic light or car. Embedded systems have a dedicated purpose and often run in real-time . The internet of things (IoT) describes a global network of connected objects that were previously 'dumb', such as smart bulbs, smart plugs and thermostats. Mainframe Mainframes are huge and very powerful computers that are reliable . Mainframes are used to process large amounts of data and can be used to solve scientific and engineering problems that require complex calculations with large datasets (e.g. weather forecasting or scientific simulations). Mainframes are reliable and secure because they have large backup capabilities . Mainframes are very expensive and require teams of experts to oversee them, and so are used only by organisations that need to process very large amounts of data quickly, such as banks and airlines . Quantum These are still experimental and in development . They work with quantum bits ( qubits ), which, unlike binary, are not limited to just two states (0 or 1). Qubits represent atomic particles, which can be in several different states at the same time . A fully working quantum computer would potentially be able to process data and perform calculations millions of times faster than currently available computers. Q uesto's Q uestions 1.3 - Computer System Types: 1. For each type of computer system , make a list of benefits , drawbacks and possible uses . a. Desktop [6 ] b. Tablet / Laptop [6 ] c. Smartphone [6 ] d. Embedded System [6 ] e. Mainframe [6 ] f. Quantum Computer [6 ] 2. Suggest and justify which type of computer system is most suitable for the following scenarios: a. Updating a spreadsheet while on a train. [3 ] b. Forecasting the next week’s weather. [3 ] c. A PE teacher recording sports day race times. [3 ] d. Playing a new video game on maximum settings. [3 ] 1.2 - Computer Components Topic List 1.4 - Connectivity

Learn about input and output devices used with computer systems. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.1 - Computer Hardware Exam Board: OCR Specification: 2016 - Unit 1 Input Devices An input device allows data, such as text, images, video or sound, to be entered into a computer system. Common input devices: Mouse Keyboard Scanner Controller Microphone Webcam Chip Reader OCR / OMR Scanner Barcode Scanner Graphics Tablet Sensors (e.g. light or temperature) Touch Screen Remote Control Biometric Scanner (e.g. fingerprint or iris) Concept Keyboard Output Devices There are many outputs created by a computer system, including printed documents, on-screen data and sound. Common output devices: Monitor Printer (e.g. inkjet or laser) Plotter Speakers Projector Alarm Light Headphones Touch Screen Braille Terminal Communication devices can be found in 1.5 . Biometric Devices A biometric device uses a human characteristic as part of its security mechanism, such as a fingerprint , iris (eye), face o r voice . Organisations using biometrics must instruct each employee to first input their information to a database , by scanning their fingerprint for example. Whenever the scanner scans a finger it searches in its database to see if the fingerprint matches one that it already holds . Only authorised employees will have already scanned their fingerprints so if there is no match then access is not allowed . Advantages of biometric devices: Security is improved as biometrics can't be shared like passwords can. Even if a password is exposed the system can't be accessed without having the biometric too. Biometric scanners verify that a user is who they claim to be. Using a biometric device (e.g. fingerprint scanner) might be quicker and easier than entering a username and password. Disadvantages of biometric devices: Can be expensive to install and all users must take the time to initially set up by entering their biometric into the database so they will be recognised by the system. Unreliable in that it can be affected by the environment (e.g. dirty fingers can't be used with a fingerprint scanner or voice recognition may not work in a loud environment). Disabled users might not be able to provide the biometric required. Privacy concerns - users might not want their personal characteristics stored on a computer system. Q uesto's Q uestions 1.1 - Computer Hardware: 1. Make a list of 5 input devices and 5 output devices . Challenge yourself to look up and include devices from this page you may not be familiar with. [10 ] 2a. State 3 human features that may be recorded by a biometric device . [3 ] 2b. Describe how a biometric device works . [3 ] 2c. A school is considering installing biometric devices to allow only sixth form students to enter certain parts of the school. Describe 3 advantages and 3 disadvantages to the school of using biometrics in this way. [10 ] Topic List 1.2 - Computer Components

Learn about protocols including FTP, HTTP, POP, SMTP, SNMP, TCP, UDP, ICMP, IP and the TCP/IP stack. Resources based on Unit F161 (Developing Application Software) for the OCR Cambridge Advanced Nationals in Computing (H029 / H129) AAQ (Alternative Academic Qualification). Qualification: Cambridge Advanced Nationals in Computing (AAQ) Certificate: Computing: Application Development (H029 / H129) Unit: F161: Developing Application Software 3.2 - Protocols Watch on YouTube: Protocols TCP/IP Stack You need to know the role and uses of specific common protocols (FTP , HTTP , POP , SMTP , SNMP , TCP , UDP , ICMP , IP ). You also need to understand the structure , content and use of the 4-layer TCP/IP stack . What You Need to Know Common Protocols A protocol is a set of rules that determines how data is communicated between devices over a network . FTP FTP (File Transfer Protocol ) is used to transfer files between computers over a network , typically between a client and a server . It is used when uploading or downloading files from a server , such as transferring website files to a web server . HTTP HTTP (HyperText Transfer Protocol ) is used to request and transfer webpages and other web content between a web browser and a web server . It is used when accessing websites or when web-based applications communicate with servers . However, HTTPS is the secure , encrypted version commonly used today. POP POP (Post Office Protocol ) is used by an email client to retrieve emails from a mail server , traditionally storing them on the user's device . It is used when emails need to be downloaded from a mail server for access through an email application , particularly where local or offline access is required . SMTP SMTP (Simple Mail Transfer Protocol ) is used to send and transfer email messages between email clients and mail servers and between mail servers . It is required when a user sends an email , including transferring that email between mail servers on its way to the recipient . SNMP SNMP (Simple Network Management Protocol ) allows network administrators and management software to monitor and manage devices on a network to collect information about their status . It is used to monitor devices such as routers , switches , servers and printers , for example checking whether a network device is operating correctly . TCP TCP (Transmission Control Protocol ) provides reliable and ordered delivery of data packets between devices . It checks that packets arrive correctly and retransmits missing packets when necessary. It is used when accuracy and reliability are more important than speed , such as transferring files , loading webpages and sending emails . UDP UDP (User Datagram Protocol ) sends data quickly , although without checking that every piece has arrived or is in the correct order , reducing delays . It is used when speed is more important than perfect delivery , such as live video/audio , online gaming and voice calls . ICMP ICMP (Internet Control Message Protocol ) is used to send network status , diagnostic and error messages between network devices . It is required when diagnosing network problems and checking whether another device can be reached , such as when using the ping command. IP IP (Internet Protocol ) addresses and routes data packets across networks by using IP addresses to uniquely identify devices . It is used when data needs to be sent between devices across networks , with IP helping packets travel from the source towards the correct destination using an appropriate route . TCP/IP Stack The TCP/IP stack is a four-layer model that describes how data is prepared , transmitted across networks and received by applications . When sending data , it travels down through the layers . When receiving data , it travels up through the layers . Different protocols are used at specific layers of the model. Application Layer This is the top layer , where network applications and services interact with the network . It includes protocols such as HTTP , FTP , SMTP , POP and SNMP . It determines how applications communicate and exchange specific types of data across a network . Example : A web browser uses HTTP to request content from a web server . Transport Layer This layer is responsible for transporting data between devices and includes TCP and UDP . It determines how data should be delivered , including whether reliability (using TCP ) or speed (using UDP ) is more important . Example : TCP can ensure that a downloaded file arrives completely and in the correct order , while UDP can prioritise speed during an online game . Internet Layer This layer is responsible for addressing and routing packets between networks and includes protocols such as IP and ICMP . It ensures packets can travel towards the correct destination using IP addresses . Example : IP is used to route packets across the internet to the destination device . Network Access Layer This is the lowest layer , concerned with how data is physically transmitted across the network using technologies such as Ethernet (a wired connection) and WiFi . It handles communication between a device and the network it is directly connected to . Example : A laptop could transmit data wirelessly to a local router using WiFi . Q uesto's Q uestions 3.2 - Protocols: 1. What is a network protocol , and why do you think protocols are needed when devices communicate ? [ 2 ] 2. State the role of FTP , HTTP , POP , SMTP and SNMP and give an example of when each would be used. [2 each ] 3. State the role of TCP , UDP , ICMP and IP and give an example of when each would be used. [2 each ] 4. Describe the structure and purpose of each of the four layers of the TCP/IP stack . [2 each ] 5. Explain how different protocols and layers of the TCP/IP stack can work together to transfer data across a network , such as sending an email on a wired connection . [ 4 ] Online games use UDP because receiving data quickly is often more important than receiving every single packet . A tiny amount of missing data may be preferable to the game pausing while it waits for it to be resent . D id Y ou K now? 3.1 - APIs Topic List 4.1 - Security Considerations

Learn about the eight rules of Boolean algebra expressions. Based on the 2020 Eduqas (WJEC) GCSE specification. 2.2: Boolean Algebra Exam Board: Eduqas Specification: 2020 Boolean algebra is used to simplify Boolean expressions so that they are easier to understand. Because calculations can use dozens of logical operators, they are simplified in Boolean Algebra using symbols rather than words. Take your time and don't panic. In an exam, you might get a list of identities (rules) to use. One tip to solving boolean algebra is to imagine that A and B are real expressions . In the examples on this page, imagine: A represents the true statement 'the sky is blue' B represents the true statement 'grass is green' 0 always means FALSE 1 always means TRUE Boolean Symbols A = NOT A A . B = A AND B A + B = A OR B Boolean Identities are the rules that are used to simplify Boolean expressions. Each identity (law) has an AND form and an OR form , depending on whether AND or OR is being used . Commutative Law AND form: OR form: This law just switches the order of the expressions . For example, 'sky is blue' AND 'grass is green' makes logical sense in either order. Idempotent Law = AND form: OR form: This law removes repetition . Complement Law NOT AND form: The sky cannot be blue and not blue at the same time, so it must be 0 (FALSE). OR form: The sky is blue or not blue must be 1 (TRUE) as it has to be one of these options. Identity Law AND form: 1 represents TRUE . Both statements are true so it can be simplified as just A . OR form: 0 represents FALSE . Because A is true, you can ignore the false statement and it can be simplified as just A . Annulment Law AND form: 0 represents FALSE . Even though A is true, a statement cannot be true and false at the same time, so it must be 0 (FALSE). OR form: 1 represents TRUE . Both statements are true so this can be simplified as just 1 (TRUE). Absorption Law AND form: OR form: Absorption law reduces a bracket into one value. If the first A is true then both values in the brackets are true but if the first A is false then both values are false. Therefore this equation relies entirely on A and can be simplified as just A . Association Law ( ) AND form: OR form: This law separates a bracketed expression that uses the same operator inside and outside the brackets by removing the brackets . Distribution Law ( ) = ( ) ( ) AND form: OR form: The value outside of the bracket (e.g. A) is multiplied by both values inside the brackets , forming two new brackets which are linked by the logical operator formerly within the bracket . Notice that the logical operator role is switched , e.g. AND switches from within the brackets, to between the new brackets. A note about distribution law - The three values may not necessarily be three separate letters (e.g. A, B and C) as B or C could be NOT A for example. A NOT value is considered a new value , e.g. A and Ā are separate values. Another note about distribution law - Exam questions may ask you to perform the distribution law (or any law) in reverse . For example, converting (A+B) . (A+C) into A + (B.C) Boolean Algebra Exam Question Some previous exam questions have listed helpful laws for you but others haven't, so you should know each individual law . In a previous exam, the candidates were given three general laws to help them . P, Q and R just represent three different values. P . 1 = P (Identity Law) P . Q + P . R = P. (Q + R) (Distribution Law) P + P = 1 (Complement Law) Using the rules above , candidates were asked to simplify the following expression : X = A . B + A . B The general laws have been give n to you for a reason. You need to look at the laws provided and see which one currently matches the expression in front of you . If you look closely in this example, the second law is very similar to the expression you are asked to simplify so you can use it to make the first simplification, just swap P for A, Q for B and R for NOT B: Using this law P . Q + P . R = P. (Q + R) X = A . B + A . B simplifies as: X = A . (B + B) Now you need to see which of the three provided laws can be used with the current expression . The third law is very similar to the expression you now need to simplify further , just swap P for B and NOT P for NOT B: Using this law P + P = 1 X = A . (B + B) simplifies as: X = A . (1) And finally, there is one law left to use. The first law is very similar to the expression you now need to simplify further , just swap P for A. Using this law P . 1 = P X = A . (1) simplifies as: X = A You have now used all three laws and the expression is fully simplified . Remember - Look at the laws that you have been given and see which law matches your expression . Q uesto's Q uestions 2.2 - Boolean Algebra: 1. Draw the example equations and write a brief description of each of the eight Boolean laws : Commutative Law Idempotent Law Complement Law Identity Law Annulment Law Absorption Law Associate Law Distributive Law 2. Below are three Boolean identities: P . P = 0 (P + Q) . R = (P . R) + (Q . R) P + 0 = P Using the three rules above , simplify the following expression: X = (A + B) . Ā This law is called ' Inverse Law ' in the Eduqas 2016 teacher guidance but ' Complement Law ' in the 2020 specification. This law is called ' Zero and One Law ' in the Eduqas 2016 teacher guidance but ' Annulment Law ' in the 2020 specification. This law is called ' Associate Law ' in the Eduqas 2016 teacher guidance but ' Association Law ' in the 2020 specification. This law is called ' Distributive Law ' in the Eduqas 2016 teacher guidance but ' Distribution Law ' in the 2020 specification. 2.1 - Logical Operators Theory Topics 3.1 - Network Characteristics

Test your understanding of printing, comments and variables. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python - Section 1 Practice Tasks Task One: Weekdays Create a program that prints all 5 weekdays , with each day on a new line . Requirements for a complete program: Use only one print line - use \n . No empty space at the start of a printed line. Example solution: Monday Tuesday Wednesday Thursday Friday Task Two: Colour & Animal Sentence Write a program that uses two variables , one for a colour and one for an animal . Print a sentence using both variables . Requirements for a complete program: Use both your variables within one print line. Include capital letters, appropriate punctuation and no irregular spacing in the printed line. Remember: Break up variables in a print line by using commas or plus signs between each part of the "sentence" . Example solutions: Have you ever seen a purple cat? A horse that was green galloped past! Three yellow ants ate my lunch. Task Three: Number, Adjective & Animal Write a program that uses three variables , a number , an adjective (descriptive word) and an animal . Print a sentence using all three variables . Requirements for a complete program: Use all three variables within one print line. Include capital letters, full stops and no irregular spacing in the printed line. Remember: Break up variables in a print line by using commas or plus signs between each part of the "sentence" . Example solutions: What? 64 sneaky elephants just ran past me! There were 12 hungry bears in the park. 85 patient spiders waited in the corner. ⬅ 1d - Using Va riables 2a - Inputting Text ➡

Learn about the elements of a data flow diagram and factors that may disrupt them. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 5.2 - Data Flow Diagrams Exam Board: OCR Specification: 2016 - Unit 2 A data flow diagram is a visual representation of how data is transferred within a system or organisation . Data flow diagrams are often abbreviated to just 'DFD '. You will need to recognise the symbols , understand the diagrams and explain how data flow can be affected . Data Flow Diagram Symbols The common symbols used in a DFD are shown below: External Entity (e.g. Employee, Customer) Alternative DFD symbols you may see on the exam paper (both sets of symbols have been accepted in previous exam papers): Process (e.g. Calculate Pay, Review Application) Data Store (e.g. Staff Database, Customer Database) External Entity Process Data Store Data Flow Level 0 data flow diagrams show the transfer of data in a simple manner . Processes may be generalised and not shown separately , for a more basic overview . Below is an example of a Level 0 DFD to show the process of an employee submitting an application to be promoted : Level 1 data flow diagrams show the transfer of data in a more detailed manner . Processes are shown separately , for a more complex and realistic overview . Below is an example of a Level 1 DFD to show the process of an employee submitting an application to be promoted . The individual processes have been expanded from the Level 0 DFD above to show how the application must first be signed off by an administrator before it is reviewed by management: Rules for Drawing a Level 1 DFD Data flows only in one direction . Every data flow is labelled (with the data itself , not the action). Every data flow connects to at least one process . At least one input or output for each external entity . Impacts Affecting the Flow of Information There are several reasons why the flow of information within an organisation may be delayed or inefficient , such as: Information characteristics e.g. information is entered incorrectly, causing delays. Human error e.g. information is lost or staff don't follow protocol. Hardware failure e.g. network connection breaking or system failure. Communication breakdown e.g. meetings postponed or emails unread. Q uesto's Q uestions 5.2 - Data Flow Diagrams: 1. Draw the symbols for the four parts of a data flow diagram . [4 ] 2. Look at the image of the Level 1 DFD . State one example of: An external entity A process A data flow A data store [1 each ] 3. Give one difference between a Level 0 and Level 1 DFD . [2 ] 4. State three rules for drawing a correct data flow diagram . [3 ] 5. After heavy snow, a school has decided to shut for the next two days. Many parents were not informed of this decision and are angry that they brought their children in. Give three reasons why the transfer of data (the data being a message about school closure) might not have flowed efficiently in this example. [6 ] 1 Level 0 Data Flow Diagram Level 1 Data Flow Diagram 5.1 - Data Types & Sources Topic List 6.1 - Security Principles

Learn about the three types of translators - assemblers, interpreters and compilers. Also, understand the differences between compilers and interpreters. Based on the 2020 Eduqas (WJEC) GCSE specification. 10.1: Translators Exam Board: Eduqas Specification: 2020 What is a translator? A translator changes (translates) a program written in one language into another language (usually machine code ). There are three types of translator : Assembler An assembler converts low level assembly language into machine code . INP STA 33 INP STA 34 LDA 33 ADD OUT HLT Interpreter An interpreter converts high-level language one line at a time into machine code and executes it. PYT HON Compiler A compiler converts high-level language into machine code for execution at a later time. The entire program is converted at once . PYT HON 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 Differences between an interpreter and a Compiler: Interpreter Compiler Execution Method: An interpreter translates source code (high level code) into machine code one line at a time . Execution Speed: An interpreter is slower than a compiler because the code must be reinterpreted each time the program is run. Complexity: Interpreters are smaller, simpler programs . Error Reporting: In error reporting, the interpreter would encounter the errors and report it to the user immediately and stops the program from running. Repetition: Interpreted programs can be edited and run without translating the whole program . Interpreters must reinterpret the program every time it is run. Execution Method: A compiler translates all the source code (high level code) into machine code in one go . A compiler produces an executable file that will run on other machines without the compiler needing to be installed. Execution Speed: Compilers can produce much more efficient code than interpreters making the compiled programs run faster . Complexity: Compilers tend to be large complex programs . Error Reporting: The compiler would analyse the entire program , taking note of where errors have occurred and record them in an error file . Repetition: Compilation requires analysis and the generation of the code only once , whereas interpreters must re-interpret each time. However, compiled programs have to be re-compiled after any changes have been made. x1 ∞ x1 Q uesto's Q uestions 10.1 - Translators: 1. Briefly describe each type of translator : a. Assembler [ 1 ] b. Interpreter [ 2 ] c. Compiler [ 2 ] 2. Compare interpreters and compilers for each of the following features : a. Execution Method b. Execution Speed c. Complexity d. Error Reporting e. Repetition [ 10 total ] 9.1 - IDE Tools Theory Topics 10.2 - Stages of Compilation

Learn about the different phases in software development models including planning, requirements, feasibility, design, construction / creation, testing, implementation (phased / parallel / big bang (crash)), documentation creation and maintenance. 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) 2.2 - Phases of Software Development Models Watch on YouTube : Phases of Software Development Models There are seven phases of software development models you need to know. As well as knowing the common phases and the key tasks within each phase , you must also understand how and why phases interact with each other and why they may iterate . Phases of Software Development Models Key Phases Planning (including requirements and feasibility ) Design Construction / Creation Testing Implementation (including phased , parallel and big bang ( crash ) methods) Maintenance Documentation creation Phased Parallel Big Bang Q uesto's Q uestions 2.2 - Phases of Software Development Models: 1. Describe the common tasks in each of the first four phases of software development . [8 ] 2. Explain the three implementation methods : phased , parallel and big bang (crash ). [6 ] 3. Describe the common tasks in the final two phases . [4 ] 4. Explain why it is important that phases interact with each other. [ 2 ] Maintenance is important - as of 2025 , some US air traffic control towers still use and maintain systems using Windows 95 and floppy disks because of their reliability . D id Y ou K now? 2.1 - Software Development Models Topic List 3.1 - Planning Projects

Learn how to easily remove objects in Greenfoot in only two lines of code. Part 4 of the Greenfoot Tutorial for the Eduqas / WJEC GCSE 2016 specification. 4. Remove Objects Greenfoot Tutorial 1. Removing Objects Watch on YouTube: Open the editor for your main character . Underneath the if statements for using the arrow keys is where we type the removal code . If you have chosen a different collectible object, type the exact name of that class instead of Orange (e.g. Apples or Ants). 2. Add Danger to your Game Use the same code as you did earlier but change the class (instead of Orange. class I have chosen Sheep. class ). Time to code your main character to be removed if they are touched by the enemy objects ! Open the editor for your enemy class . The removal code is placed beneath the code you have already written. Check out the extension page if you want the game to stop when the main character is removed. < Part 3 - Random Movement Part 5 - Play Sounds >