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3.1b: Network Hardware & Internet Exam Board: OCR Specification: J277 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

Exam Board: OCR 5.1 - Computer Legislation Specification: A-Level 2015 An instruction set is a list of all the instructions that a CPU can process as part of the FDE cycle . CPUs can have different sets of instructions that they can perform based on their function. The two most common instruction sets are the simpler RISC (Reduced Instruction Set Computer ) and more complicated CISC (Complex Instruction Set Computer ). Instruction Sets This page is still being updated. Graphical Processing Unit What is cache memory? Cache memory is temporary storage for frequently accessed data . Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Multicore & Parallel Systems What is cache memory? Cache memory is temporary storage for frequently accessed data . Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Multicore & Parallel Systems What is cache memory? Cache memory is temporary storage for frequently accessed data . Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Q uesto's Q uestions 5.1 - Computer Legislation: 1. What is cache memory ? [ 2 ] 4.3b - Flip Flops, Adders, Laws & Maps Theory Topics 5.2 - Moral & Ethical Issues

4.1: Security Threats Exam Board: OCR Specification: J277 Types of 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. 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 . 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. Brute-Force Attack 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. 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 . Data 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. 4.1 - Security Threats: 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. Describe what an SQL injection is and how an attacker would use it. [ 3 ] 4a. Describe what a DoS attack is and its impact . [2 ] 4b. Describe how a DDoS attack is different to a DoS attack . [2 ] 5a. Describe a brute-force attack. [ 2 ] 5b. Describe social engineering and give an example of when it might be used . [2 ] 5c. Describe interception . [2 ] Q uesto's Q uestions 3.2b - Protocols & Layers Theory Topics 4.2 - Preventing Vulnerabilities

8.3: Writing Algorithms Exam Board: Eduqas / WJEC Specification: 2020 + Pseudocode Reminder Generally, pseudocode can be written in any way that is readable and clearly shows its purpose. However, the Eduqas exam board advises that pseudocode for the programming exam should follow the conventions below : Annotation { Write your comment in curly brackets} Define data type price is integer firstname is string Declare a variable's value set price = 100 set firstname = "Marcella" Input / output output "Please enter your first name" input firstname Selection (must have indentation) if firstname = "Steven" then output "Hello" + firstname elif firstname = "Steve" then output "Please use full name" else output "Who are you?" end if Iteration (while loop) while firstname ! = "Steven" output "Guess my name." input firstname repeat Iteration (for loop) for i in range 10 input item next i Define a subroutine Declare Sub1 [Subroutine content indented] End Sub1 Call a subroutine call Sub1 Writing Algorithms In an exam you may be asked to write an algorithm using pseudocode . Previous exams have offered up to 10 marks for a single algorithm . While this may seem daunting, it means you can still gain marks for an incomplete program , so don't leave it blank no matter what! You must decompose the problem and break it down into more manageable chunks . Here's an example question : “A teacher is marking tests. Write an algorithm that allows the teacher to input the number of tests to mark and then the mark of each test. Output the average mark, highest mark and lowest mark. The tests are marked out of 100.” This specific algorithm can be broken down into pre-code and three main parts : Part 0: Declare and assign variables. Part 1: Input the number of tests to mark. Part 2: Input the mark of each test. Part 3: Output the average, lowest and highest marks. Part 0: Variables Read the question carefully and work out the variables you will need in your algorithm. I have highlighted them in blue below: “A teacher is marking tests. Write an algorithm that allows the teacher to input the number of tests to mark and then the mark of each test . Output the average mark , highest mark and lowest mark . The tests are marked out of 100.” There is an additional variable to track as the average mark can only be worked out if we also know the total marks . number_of_tests is integer test_mark is integer average_mark is real highest_mark is integer lowest_mark is integer total is integer number_of_tests = 0 test_mark = 0 average_mark = 0 highest_mark = -1 lowest_mark = 101 total = 0 Before you write the actual program, you must declare the variables you will need and assign values to them. Firstly, declare the data type of each variable . A whole number is an integer and a decimal number is a real . The average must be a real data type because it is the result of division (total ÷ number_of_tests) and could be a decimal number . When assigning values, most numerical variables will be 0 . Most string values would be " " . However this question is a bit more complicated - the highest mark must start as a really low value and the lowest mark must start as a really high value . This is ensure the first mark entered becomes the highest and lowest mark - this will make sense later. Part 1: Input Number of Tests output “Enter the number of tests to mark: ” input number_of_tests After declaring and assigning your variables the next parts will depend on the algorithm you need to write. This example requires the user to input the number of tests . Part 2: Input Each Mark (Loop) for i = 1 to number_of_tests output “Enter the test mark: ” input test_ mark For part 2 we need the teacher to enter each test’s mark . This is best done as a loop as we do not know how many tests the teacher has to mark until they have typed it in (part 1). All code within the loop must be indented . if test_mark > highest_mark then highest_mark = test_mark endif if test_mark < lowest_mark then lowest_mark = test_mark endif We also need to work out what the highest and lowest marks are. This must be done within the loop as the test marks are entered. The test mark is compared to the current highest and lowest marks . If it is higher than the current highest mark it becomes the new highest mark . If it is lower than the current lowest mark it becomes the new lowest mark . This is why we set the highest_mark and lowest_mark to extreme values at the start - so the first mark entered becomes the new highest and lowest . total = total + test_mark next i The final steps of part 2 are to update the total marks and to close the loop . The total is increased by the test mark that has been entered. The ‘next i ’ command states that the current iteration has ended . The indentation has now stopped. Part 3: Outputs average_mark = total / number_of_tests output “The average mark is:” , average_mark output “The highest mark is:” , highest_mark output “The lowest mark is:” , lowest_mark Before the average can be output, it must be calculated by dividing the total by the number of tests . Then the average , highest and lowest marks can be output . Full Answer number_of_tests is integer test_mark is integer average_mark is real highest_mark is integer lowest_mark is integer total is integer number_of_tests = 0 test_mark = 0 average_mark = 0 highest_mark = -1 lowest_mark = 101 total = 0 output “Enter the number of tests to mark: ” input number_of_tests for i = 1 to number_of_tests output “Enter the test mark: ” input test_ mark if test_mark > highest_mark then highest_mark = test_mark endif if test_mark < lowest_mark then lowest_mark = test_mark endif total = total + test_mark next i average_mark = total / number_of_tests output “The average mark is:” , average_mark output “The highest mark is:” , highest_mark output “The lowest mark is:” , lowest_mark This example is slightly more complicated than some of the recent previous exam questions for writing algorithms. Remember to decompose the problem by identifying the variables you need first. Q uesto's Q uestions 8.3 - Writing Algorithms: 1. A violin player performs a piece of music 8 times . They record a score out of 5 how well they think they performed after each attempt. Write an algorithm using pseudocode that allows the violinist to enter the 8 scores and displays the highest score , lowest score and average score . An example score is 3.7. [10 ] 2. A cyclist wants a program to be made that allows them to enter how many laps of a circuit they have made and the time in seconds for each lap . For example they may enter 3 laps, with times of 20.3 , 23.4 and 19.8 seconds . The program should output the quickest lap time , slowest lap time , total amount of time spent cycling and the average lap time . Create an algorithm using pseudocode for this scenario. [10 ] 8.2 - Understanding Algorithms Theory Topics 8.4 - Sorting & Searching

The CPU Key Facts! CPU stands for C entral P rocessing U nit . The CPU is known as the brain because it is used to process data and instructions . What is clock speed? The clock speed is the measure of how fast the CPU runs . Clock speed is measured in Gigahertz (GHz) . 1 GHz is 1 billion cycles a second! What does the CPU do? The CPU’s job is to perform the FDE ( Fetch-Decode-Execute ) cycle very, very quickly. The FDE cycle allows a computer to run programs by processing instructions. The faster the clock speed of a computer, the more FDE cycles can be processed. What are the components of the CPU? The control unit directs the flow of data and information into the CPU . It also controls the other parts of the CPU. ALU stands for Arithmetic Logic Unit . It performs simple calculations and compares data. The registers are temporary storage spaces for instructions inside the CPU. What is overclocking and underclocking? Clock speed: 3.7 GHz 3.9 GHz 3.5 GHz Overclocking is when the computer's clock speed is increased higher than the recommended speed. This will make the computer perform faster but it can lead to overheating and could damage the computer . Underclocking is when the computer's clock speed is decreased lower than the recommended speed. This will make the computer perform slower but will increase the lifespan of the computer . KS3 Home

1.4 - Internet Connections Exam Board: OCR Specification: 2016 - Unit 2 The internet i s a global network of interconnected networks . There are multiple methods of connecting to the internet . Wired Connections Copper Cables Copper cables are a cheaper type of wired internet connection that may be poorly insulated and therefore susceptible to electromagnetic interference . Copper cables are more likely to suffer from attenuation (network distortion ). However, they are malleable (easier to bend) and less likely to break than other cables such as fibre optic. They have a lower bandwidth - cannot transmit as much data at once - than fibre optic cables. Fibre Optic Cables Fibre optic cables are a very fast but expensive type of wired internet connection. Signals are transmitted as waves of light through a glass tube. Because of this fibre optic cables are not affected by electromagnetic interference and suffer less from attenuation . Fibre optic cables have a higher bandwidth - can transfer more data at one time - than copper cables but they are more fragile . Wireless Connections Bluetooth Bluetooth is a temporary short-range communication between devices within a limit of about 10 metres . For example, Bluetooth can be used to transfer audio files from one smartphone to another. The close proximity is a disadvantage but no other hardware is required for a connection. Microwave Microwave connections use radio waves to send signals across a large area via microwave towers . It can transmit a large amount of data but antennas must be in the line of sight of each other with no obstructions . Microwave connections are affected by bad weather , leading to higher chances of attenuation (network distortion ). Satellite Satellite networks use point-to-multipoint communication by using satellites above the Earth's atmosphere that receive a transmission and rebroadcast them back to Earth. Because of the distance between the communication device and the satellite (roughly 45,000 miles), there is a delay between data transmission and it being received. GSM / 5G GSM (Global System for Mobile communications ) is a technology for allowing mobile phones to connect to a network for calls and text messages. Advances in mobile technology are classified by generations such as 4G and 5G (the current generation). Each generation is generally faster, more secure and allows for new opportunities. Connection Characteristics When connecting to the internet there are several characteristics that a user must consider: Strength Range Latency Bandwidth Storage Capacity Contention Latency is the delay when sending data across a network. Bandwidth is the maximum amount of data that can be sent across a network at once . Contention refers to whether a network is dedicated ( uncontended ) or shared between users ( contended ). Q uesto's Q uestions 1.4 - The Internet: 1. Compare the differences between copper and fibre optic cables (possibly in a table) by the following features: a. Price b. Bandwidth c. Interference d. Attenuation e. Malleability / Fragility [2 each ] 2. Describe each of the different types of wireless connection . Try to list 1 advantage and 1 disadvantage of using each type. a. Bluetooth b. Microwave c. Satellite d. GSM / 5G [5 each ] 3a. State the 6 characteristics of a network. [6 ] 3b. Describe what is meant by the following characteristics : i. Latency ii. Bandwidth iii. Contention [1 each ] 1.3 - Access & Storage Devices Topic List 1.5 - WWW Technologies

3. Random Movement 1. Code for Random Movement Greenfoot Tutorial Watch on YouTube: Right-click on your enemy class on the main screen and select ' Open editor '. The enemy character should always be moving, so start with move(1); Next we will use an if statement to start the random movement. This code generates 10 random numbers and if it is less than 1 then it will run the proceeding code. If we don't do this, the character will turn too much or too little . This code generates a random angle between 0 and 90. The - 45 part is necessary otherwise the character will always move to the right . See the diagram below for an explanation: 2. Bounce at World Edge You may have noticed that the enemy objects can get 'stuck' in the corners or when they hit the edge of the world. In the act() method, below the random movement code , add the code in the red box . This code checks to see if the object is at the edge , and turns it around ( 180 degrees ) if it is. 3. Compile and Run Click the Compile button at the top of the code editor . Then you can go back to the main Greenfoot window and click Run to test if your enemy objects move . Click on me if you've got an error that you're stuck with. < Part 2 - Movement with the Arrow Keys Part 4 - Remove Objects >

Exam Board: OCR 3.1g - Pathfinding Specification: A-Level 2015 An instruction set is a list of all the instructions that a CPU can process as part of the FDE cycle . CPUs can have different sets of instructions that they can perform based on their function. The two most common instruction sets are the simpler RISC (Reduced Instruction Set Computer ) and more complicated CISC (Complex Instruction Set Computer ). Instruction Sets This page is still being updated. Graphical Processing Unit What is cache memory? Cache memory is temporary storage for frequently accessed data . Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Multicore & Parallel Systems What is cache memory? Cache memory is temporary storage for frequently accessed data . Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Multicore & Parallel Systems What is cache memory? Cache memory is temporary storage for frequently accessed data . Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Q uesto's Q uestions 3.1g - Pathfinding: 1. What is cache memory ? [ 2 ] 3.1f - Searching Algorithms Theory Topics

Greenfoot Code Glossary Greenfoot Home This code will work for Version 2.4.2 which is used in Component 2 of the 2016 WJEC/Edquas specification . Key Down 270 if (Greenfoot.isKeyDown("right" )) { setRotation(0); move(1); } 180 90 0 Bounce At Edge if (isAtEdge()) { turn(180); } move(1); if (Greenfoot.getRandomNumber(10)<1) { turn(Greenfoot.getRandomNumber(90) - 45); } Random Remove Object if (isTouching(Apple.class )) { removeTouching(Apple.class ); } Play Sound Greenfoot.playSound("pop.wav" ); Stop Greenfoot.stop(); Counter - (Write this code when an object is removed) Counter counter = (Counter) getWorld().getObjects(Counter.class ).get(0); counter.add(1); Stuck? If you start typing but can't remember what commands come next, press Ctrl and Space together to show a list of all possible commands that you can use.

7. Head Tags HTML Guide Watch on YouTube: Remember that all HMTL documents are split into the head and the body. The following tags must be typed inside of your head tags . title Title The title is not the main heading. The title is the page title itself that you can see at the tab at the top of your web browser. Add a title to your web page. metadata Metadata Metadata is information about the web page itself. This commonly includes data about the author, the page's contents and any keywords. Metadata will not appear on the actual web page . Add meta data tags between your head tags for author, keywords and a description. The meta tag is made up of a name and content . Author represents who created the web page. Keywords are commonly used words. Description is used for displaying search engine results (such as a Google search). Next it is time to embed YouTube videos into your web page. 6. Organisation Tags HTML Guide 8. Videos

2.3 - Quality of Information Exam Board: OCR Specification: 2016 - Unit 2 Information Characteristics Valid Information This is correct, up-to-date and complete information that fits its purpose . For example, detailed end-of-year financial data in the form of graphs. Biased Information This is technically correct, but slanted , information that presents a one-sided view . For example, end-of year financial data that focuses on profits and ignores significant losses. Relevant Information Information should be appropriate for the required purpose . Irrelevant information may get in the way of correct decision making. Accurate Information Information should be carefully selected and entirely correct , inaccurate information can lead to unwanted consequences such as higher costs and missed deadlines. Reliable Information Information from a source that can be verified and confirmed to be correct . For example, BBC News is a more reliable information source than social media posts. Information Quality The quality of information that an organisation uses will have a significant impact on further processes and decisions. Good quality information that is accurate , valid or reliable can lead to better strategic decisions , meeting deadlines and innovation . Poor quality information that is biased , inaccurate or out of date may lead to negative consequences such as loss of customer trust , fines and legal challenges . Positive Effects of Good Quality Information Reliable information received by the management team . Good quality research information. Good quality sales information. Accurate cost projection information. Informed decisions with a higher chance of success . Can lead to innovation and better understanding . Strategic decisions and planning ahead . Projects will stay within their budget . Accurate time expectations . Projects will be completed on time . Negative Effects of Poor Quality Information Biased survey with inaccurate results . Inaccurate stock information. Out of date information received by management . Inaccurate data has led to poor reviews online . Inaccurate time expectations . Misinformed decisions , not responding to customers needs . ??? Inaccurate delivery times , customers unhappy . Too much / little stock. Miss out on opportunities , possible fall in profits . Loss of customer trust , loss of customers and reputation . Financial issues . Projects take longer , cost more , stakeholders unhappy . Possible project failure . Q uesto's Q uestions 2.3 - Quality of Information: 1. Describe 5 characteristics of information . [10 ] 2. Explain 5 positive impacts of good quality information . [10 ] 3. Explain 5 negative impacts of poor quality information . [10 ] 2.2 - Information Classification 2.4 - Information Management Topic List

top Python 7a - Procedures Subroutines A subroutine is a section of code that can be re-used several times in the same program. It is separate from the main code and has to be ‘called’ upon. Subroutines are designed to be repeated, and they have three key benefits: Subroutines make programs easier to read . They reduce the duplication of code . Complex problems are broken down into smaller chunks . There are two types of subroutines: procedures and functions . A procedure just executes commands , such as printing something a certain number of times. A function produces information by receiving data from the main program and returning a value to the main program. For example, a function could take the radius of a sphere from the main program, calculate a sphere’s area and return the value of the area to the main program. A function generally requires parameters to work – these are the values to be transferred from the main program to the subroutine. Procedures A procedure i s a type of subroutine that runs independently of the main program . A subroutine must be defined at the top of the program before the main code by typing def and the name of the subroutine . In the example below I have created a procedure to calculate the multiplication of two numbers and a separate procedure for the division. The main program starts beneath the subroutines , against the left side of the editor. I have created a while true loop that asks the user if they want to multiply, divide or stop the program. If they choose to multiply, the multiply subroutine is called . This initiates that subroutine then returns to the main program when it is complete. If they choose to divide, the divide subroutine is called instead. Typing stop will break (end) the loop. Here you can see the two parts of the program put together. Subroutines must be written first , with the rest of the program underneath. Subroutines can be called in any order . Below I have run the program and divided then multiplied before breaking the loop: Practice Tasks 1 1. Create a procedure called hello that just prints “Hello there! ”. In the main program create a for loop that calls the procedure 10 times. You must use a procedure. 2. Create a program with two procedures. The addition procedure allows the user to add two numbers together. The subtraction procedure allows the user to take a number away from another. Use a while true loop in the main program and a break to stop the loop. Example solution for #1: Local & Global Variables Programming languages use local variables and global variables . A global variable can be used anywhere in the program . A local variable can only be used in the subroutine it is created in . I have adapted the multiply / divide program below to use global variables by stating the global command and the name of the variables in each subroutine. This allows me to ask the user to enter numbers in the main program. Practice Tasks 2 1. Adapt your addition / subtraction program from the first practice task section to use global variables. 2. Create a program that asks the user to enter their name in the main program. Call a subroutine that greets the user using the name variables. You must use a procedure and a global variable . Example solution for #2: ⬅ Section 6 Practice Tasks 7b - Functions ➡