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Learn about the six parts of a data packet and how packet switching works. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.2: Data Packets & Switching Exam Board: Eduqas / WJEC Specification: 2020 + What is a data packet? 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. Contents of a Data Packet Data packets contain six distinct pieces of data which are used to redirect the packets towards the destination address. Packet Switching vs. Circuit Switching The key difference is that a circuit-switched network sends data along the same route . A packet-switched network sends data packets along different routes . Packet Switching With a packet-switched network the data is split into packets . The data packets are transmitted over a network and may take different routes to its destination. When all the packets have arrived the data is reassembled . The Internet is an example of a packet-switching network. Advantages of Packet Switching: Transmission is more secure as it is harder for a hacker to intercept complete data because it can take different routes . If a network device fails the data packets can take an alternative route . Data packets can be sent efficiently and individually across less busy routes . Disadvantages of Packet Switching: Reassembling the data takes longer because packets may arrive out of order . It is less reliable than circuit switching as some data packets may not reach the destination (this is called packet loss ). Circuit Switching When data is transmitted over a circuit-switched network all of the data takes the same route to the destination address in one continuous stream . The data is quickly reassembled at the destination because it is already in the correct order . The old telephone system is an example of a circuit-switched network. Advantages of Circuit Switching: Reassembling the data is quick because the packets arrive in the order that they were sent. It is more reliable than packet-switching because data is sent in one continuous stream . The transmission is fast and should encounter fewer errors - once the connection has been securely established . Disadvantages of Circuit Switching: Less secure as hackers could intercept the data and more easily access the data as it all takes the same route. Establishing a connection takes time to set up. If any device fails on the route then the whole connection breaks and data transfer will be incomplete. Q uesto's Q uestions 3.2 - Data Packets & Switching: 1. Draw the data packet diagram and label all 6 pieces of information . [ 6 ] 2a. Describe how packet switching works . [3 ] 2b. Describe the advantages of packet switching . [3 ] 2c. Describe the disadvantages of packet switching . [2 ] 3a. Describe how circuit switching works . [3 ] 3b. Describe the advantages of circuit switching . [3 ] 3c. Describe the disadvantages of circuit switching . [3 ] 3.1 - Network Characteristics Theory Topics 3.3 - Network Topology

Learn about different formats for presenting data on the internet including webpages, blogs, streamed video and audio, document stores and RSS feeds. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 1.6 - Information Formats Exam Board: OCR Specification: 2016 - Unit 2 The following formats are used to display information on the internet . Web Pages Web pages can be used for a diverse range of purposes including advertising products, reporting information , displaying images and eCommerce (online shopping). There are two types of web page: Static web page Static web pages contain content that is pre-built and remains the same each time the page is loaded . Static web pages are cheaper and easier to create and load quicker ; they use basic HTML. It can be changed by the site editor but will appear the same for everyone who has access to it, such as a classic promotional website for a small company. Dynamic web page Dynamic web pages are generated when they are loaded and can appear different to different users . Dynamic web pages are harder to code but they can be linked to databases to allow them to show personalised content to whoever is viewing the site; they are written in server-side languages like PHP. The Amazon homepage is an example of a dynamic web page as personalised deals based on previous user history will be shown if you are logged in with an account. Blogs Blogs are used to share information with like-minded individuals, such as those who enjoy the same hobbies or beliefs . Charities , game developers and other businesses also use blogs as a way of updating their customer base with what they have done or what they are working on. Blogs can feature multimedia such as text, images, videos and links to other sites. Advantages of Blogs Disadvantages of Blogs ✓ Share information with followers in the format of text, images and video . ✓ Blogs and vlogs can unite people with similar interests , such as a cookery blog or travel vlog. X Takes a lot of effort and time to create posts, especially if videos need to be edited before posting. Potential customers could be lost if blogs aren't updated regularly . X It can be difficult to build up a customer base directly from a blog. Posts must be engaging , researched and correct . Podcasts A podcast is a downloadable audio file , usually on a certain topic such as sports or gaming that can be listened to when convenient for the user. Spotify and Apple Music have a wide library of podcasts. Advantages of Podcasts Disadvantages of Podcasts ✓ Podcasts are not (usually) recorded live , so they can be edited and uploaded at a certain time each week. ✓ Podcasts can be listened to when convenient for the user, so they can't 'miss' it and can catch up when is best for them. ✓ Podcasts are becoming more and more popular , so the possible audience base is growing each year. Celebrity guests are one way to entice more listeners. X Takes time to record a podcast, especially if they need to be edited to add in music or sound effects or to remove mistakes . X It can be difficult to build up an audience directly from a podcast. Podcasts should be on a topic that interests people and spoken in an engaging way. Streamed Audio & Video Streaming is the process of receiving video / audio data in a continuous flow . This allows the user to access the video / audio immediately , without having to wait for the file to download entirely. For example, the BBC provide live radio streaming online for their radio shows and BBC iPlayer allows users to watch 'catch up' programs that previously aired. YouTube is a widely-used streamed video platform and Spotify is a popular streamed audio service. Advantages of Streamed Media Disadvantages of Streamed Media ✓ Streaming does not require data to be downloaded entirely before use - users can watch / listen as soon as the connection starts . ✓ Streaming is harder for users to share than downloading a file . Netflix uses this as a form of piracy protection . X Streaming requires high bandwidth so users may suffer performance issues on slower devices and networks . X Streaming requires a constant network connection compared to downloadable media which can be used when offline / outside. Social Media Channels Social media channels provide a huge amount of data on users in an informal space. Organisations can receive feedback through user posts and comments . Real-time statistics like views, likes and shares provide an insight to user opinion . Social media channels include traditional sites such as Facebook and Twitter as well as business and recruitment platforms such as LinkedIn . Discussion boards and forums , such as Reddit , are increasingly popular for users to discuss similar hobbies and interests such as politics, gaming and healthy eating. Advantages of Social Media Disadvantages of Social Media ✓ Social media can increase a business' online presence as it is online 24/7 for users to comment and interact with posts. ✓ Posts can be shared between users and their contacts, allowing a post to 'go viral' and be seen by potentially millions of viewers . ✓ Posts can be shared in different information styles such as text , images , video or hyperlinks to other websites. ✓ Businesses can use social media to communicate with their customer s , such as direct messages on Facebook if a customer is unhappy. X Businesses may need to hire a social media manager to interact with customers , update posts and remove spam. X Negative posts can be shared and spread very quickly , such as if a customer complains about how a business treated them poorly. X Businesses must be cautious about what they post , to not accidentally offend others and damage their reputation . Emails Emails can be used to provide information to a large amount of people almost instantly . A company may use an email to advertise new products , inform potential customers of a marketing promotion or target specific users based on previous interactions. Advantages of Emails Disadvantages of Emails ✓ Faster (almost instant) and cheaper (usually free) to send an email compared to traditional letters . ✓ Files can be attached to the email, such as images, videos or forms to complete. ✓ An audit trail can be kept, recording communication between the company and its customers. ✓ Emails can be sent, delivered and read at the user's convenience and to any internet-enabled device across the world . X An internet connection is required to open and read the email. Larger attachments may not open on mobile devices. X Malware can spread through email attachments. Phishers use emails to gain access to personal information and account details . X Some attachments sent via email may be unreadable on different devices / operating systems. X Emails may automatically go into the spam / junk folder and be deleted without being read . Document Stores Document stores allow users to store online files in cloud storage . Common services are Google Drive , Dropbox and Microsoft's OneDrive . Storing documents in the cloud allows users to edit and access them from any location with an internet connection and opens up opportunities for collaboration . Many organisations offer cloud storage space for free up to a certain amount before charging customers for more data. Document stores are very convenient for users and replace the need for portable storage devices like USB sticks. Teachers can use documents stores to share resources with other staff in a school . Documents stores can only be accessed with an internet connection so files will be unavailable during maintenance or network failure. Users rely on the cloud hosting provider, such as Microsoft and Google to keep the data secure and available . RSS Feeds RSS Feeds (short for Rich Site Summary ) allow users to subscribe to updates from their favourite websites. It is a web feed that updates whenever a subscribed site releases new information. For example, the BBC used to post updates for important news headlines which appeared in a subscribed user's RSS feed. As of 2020 most browsers no longer have built-in RSS functionality and it is rarely used . Q uesto's Q uestions 1.6 - Information Formats: 1. Describe the difference between static and dynamic web pages . [4 ] 2. For each type of information format describe its advantages and disadvantages . a. Blogs [8 ] b. Podcasts [8 ] c. Streamed Audio / Video [8 ] d. Social Media [8 ] e. Emails [8 ] 3. Explain how document stores could be used by organisations and individuals . [4 ] 4. Explain what an RSS feed is and how an organisation could use it . [3 ] 1.5 - WWW Technologies Topic List 1.7 & 1.8 - Internet Pros & Cons

Learn about the negative impacts that data loss will have on an organisation including reputation loss, fines and possible bankruptcy. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 6.3 - Impacts Exam Board: OCR Specification: 2016 - Unit 2 If a risk to data (see 6.2 ) occurs then there are a number of different impacts that may consequently negatively affect an organisation . Loss of Intellectual Property 'Intellectual property ' refers to anything that an organisation or individual has designed, developed or created themselves . For an individual, this could be a manuscript , artwork or piece of music . For an organisation, it could be primary data they have collected, blueprints for an upcoming design or a report following data analysis. The impact of having intellectual property lost depends on the property itself and how easy it would be for the victim to recreate or recollect the data . Competitors that stole intellectual property could use it at their advantage. Also, the effect of an upcoming announcement to the public would decrease if it was leaked ahead of time. In 2017 HBO suffered large property leaks when Game of Thrones episodes were stolen before air date resulting in pirated versions appearing online well before they were due to be shown on TV. Loss of Service and Access If usernames and passwords are stolen then individuals may be unable to access services that they have paid for, an example being if WiFi details were stolen so that a hacker can access the internet using someone else's account. If a hacker is permitted access to a system they can change the account settings such as the password to lock out the original owners of that account, leaving them without access. Other services can be targeted with malicious attacks like a DDOS attack so that users cannot log into a web page or online service. If users cannot access an account they may use alternative methods and providers , such as avoiding one type of cloud storage provider that has let them down and choosing another. Breach of Confidential Information Confidential information is of a highly sensitive nature and could lead to other negative impacts if it got into the hands of unauthorised people . Confidential information, such as medical histories, should be stored securely with multiple physical and logical protections in place to ensure that it keeps its integrity . If confidential information was breached then it could lead to a loss of reputation as the holder would be regarded as ineffective at protecting the data . Legal consequences would also follow as the Data Protection Act ( 2018 ) would be broken : fines, court cases and even imprisonment would be possible further impacts. An organisation would expect to see penalties from the Information Commissioner's Office (ICO) if they failed to protect personal details by breaking the DPA . Loss of Third Party Data Many organisations will store data not only for their own purposes but for other individuals and businesses too; a key example being cloud storage providers . Users can store data on public cloud services such as Google Drive or DropBox and access their information using the internet from any networked device they please. If services like cloud storage services are hacked or taken offline (e.g. because of an attack or network problems) and data is lost then customers, especially those that pay, will be furious. This will lead to a loss of reputation, trust and even legal proceedings if personal and sensitive data is lost. Larger businesses will use private cloud storage, hosted in data centres that they maintain themselves, to avoid relying on third parties . Loss of Reputation Organisations spend years to build up a reputation where customers trust them and want to use their products or services. Data loss can immediately destroy that reputation and cause once-loyal customers to look elsewhere and choose their competitors . Failing to keep data safe means that an organisation has been unable to follow their legal and moral duty of keeping information secure and could lead to a loss of trade , resulting in reduced earnings and sales . Identity Theft If an individual's personal information is stolen by attackers then one impact is identity theft - when the attacker uses the victim's data for fraud or impersonation . Identity theft can lead to financial loss to the victim if loans , products or services are purchased in their name . The victim may have to contact their bank and other organisations to cancel transactions and there is no guarantee their money will be returned. Credit checks may be affected, leading to future financial difficulty for the victim. Threat to National Security If data of a classified nature (such as military arrangements, security weak-points or upcoming government plans) is lost and falls into the hands (most probably by hacking) of those who intend to bring harm to the country then the consequences can be disastrous. Spies of foreign countries or terrorists could use classified information to target vulnerable locations or events resulting in casualties. Threats could also be economic in nature if large amounts of money are stolen or redirected to malicious bodies. Recent Examples of Security Failure Q uesto's Q uestions 6.3 - Impacts: 1. Describe how each of the impacts above could affect a bank storing large amounts of customer data including financial records. [12 ] 2. Research three recent hacking examples . For each situation describe the impacts that occurred as a result of data loss . [12 ] Click the icons to read BBC News articles about recent examples of hacks and security breaches . Virgin Media Boots Marriott Hotels Facebook Messenger 6.2 - Risks Topic List 6.4 - Protection Measures

Navigate between all Unit 2 (Global Information) topics in the OCR Cambridge Technicals Level 3 IT 2016 specification. OCR Cambridge Technicals IT Level 3 Unit 2: Global Information These pages are based on content from the OCR Cambridge Technicals 2016 Level 3 IT specification . This website is in no way affiliated with OCR . This qualification stops in July 2025. The pages on the site will remain for at least two years. LO1 (Devices & The Internet ) 1.1 - Holders of Information 1.2 - Storage Media 1.3 - Access & Storage Devices 1.4 - Internet Connections 1.5 - WWW Technologies 1.6 - Information Formats 1.7 & 1.8 - Internet Pros & Cons LO2 (Information Styles & Quality ) 2.1 - Information Styles 2.2 - Information Classification 2.3 - Quality of Information 2.4 - Information Management LO3 (Categories & Analysis ) 3.1 - Data vs. Information 3.2 & 3.3 - Information Categories 3.4 - Stages of Data Analysis 3.5 - Data Analysis Tools 3.6 - Information Systems LO4 (Legislation ) 4.1 - UK Legislation 4.2 - Global Legislation 4.3 - Green IT LO5 (Flow of Information ) 5.1 - Data Types & Sources 5.2 - Data Flow Diagrams LO6 (Security & Protection ) 6.1 - Security Principles 6.2 - Risks 6.3 - Impacts 6.4 - Protection Measures 6.5 - Physical Protection 6.6 - Logical Protection

The first part of a quick guide to the basics of Python aimed at Key Stage 3 students. Learn about comments and printing. Python - #1 - The Basics 1. Start with Commenting Programmers write A LOT of code. They need to understand exactly what they have written, especially if they are working as part of a team or returning to code after working on other projects. To help them understand what they have written, programmers use comments to annotate (explain) their code . Task 1 - Create a new Python program and use # to write a comment that says your name and the date. Save the file as 1-Basics.py In Python, type the # symbol then your message to write a comment. Comments are not printed when you run a program! It is a good idea to start every program with a comment, so you know what the program is about . 2. Printing to the Screen The most basic and common command you will use in Python is print . Inside the print brackets, you can write a message within speech marks . Your print command should turn purple - don't use any capital letters in Python unless it is inside speech marks! Task 2 - Write a nice message by using the print command, brackets and speech marks. Press F5 to run your program. 3. More Printing You can write multiple print lines one after another to print on different lines. Task 3 - Add two more print lines to your program. You can choose any message that you like. 4. New Lines You can use the special command \n to start a new line . This allows you to write on multiple lines but only use one print line. Use the backslash ( \ ) not the forward-slash ( / ). Task 4 - Use \n to write a 3 sentence conversation in only one line of code. Challenge Programs Use everything that you have learned on this page to help you create these programs... Challenge Task 1 - Days of the Week Create a new Python program. Save it as ' 1-Week.py ' Add a comment at the top with your name and the date. Create a program that prints the days of the week, with each day on a new line. BONUS : Try to use only one print line. BONUS : Have no empty spaces at the start of each line. When you run it, it should look like this: Challenge Task 2 - Conversation Create a new Python program. Save it as ' 1-Conversation.py ' Add a comment at the top with your name and the date. Create a program that prints a 6-line conversation between two people. It is up to you what these two people are talking about. BONUS : Try to use only one print line. BONUS : Have no empty spaces at the start of each line. When you run it, it could look something like this: #2 Variables >>>

Learn about how to write algorithms, including pseudocode and the different flowchart symbols. Based on the 2020 Eduqas (WJEC) GCSE specification. 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 most common errors made in Grennfoot when making a game and how to fix them, including when missing punctuation is expected or the end of file is reached while parsing. Common Greenfoot Errors Greenfoot Home If the world becomes greyed out and you can't click on anything then an error has occurred. The actor with the error will have red lines on it. When an error occurs, a red squiggly line will appear underneath the problem. Hover your mouse over the line and a helpful message will appear to help you solve the issue. Some of the more common errors (and how to fix them) are listed below: ; expected Every line with a white background must end in a semi colon ( ; ) ) expected You have missed a bracket . Count the number of open brackets and the number of closed brackets on a line and make sure you have an equal number of both. reached end of file while parsing You are missing at least one curly bracket ( } ) at the end of your program . Press enter to move onto a new line at the bottom; you must have a closed curly bracket with a yellow background and another closed curly bracket with a green background . cannot find symbol You have typed a command incorrectly . Greenfoot uses a system where commands have no spaces and each word after the first word is uppercase . Such as isKeyDown not IsKeyDown and not isKeydown. Check your spelling and capitals carefully. 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.

Based on the OCR Computer Science A-Level 2015 specification. Exam Board: OCR 4.3b - Flip Flops, Adders, Laws & Maps 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 4.3b - Flip Flops, Adders, Laws & Maps: 1. What is cache memory ? [ 2 ] 4.3a - Logical Operators & Truth Tables Theory Topics 5.1 - Computer Legislation

The homepage for the HTML section on CSNewbs. Learn how to create an HTML website from scratch and how each tag works. I'm Arthur the Alligator and I'm here to teach you HTML. HTML GUide Show me how to make a webpage in HTML from scratch. List of Tags Show me a list of tags I can use.

Based on the OCR Computer Science A-Level 2015 specification. Exam Board: OCR 4.1a - Data Types & Character Sets 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 4.1a - Data Types & Character Sets: 1. What is cache memory ? [ 2 ] 3.4b - HTML, CSS & JavaScript Theory Topics 4.1b - Denary, Binary & Hexadecimal

Test your understanding of for loops and while loops in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python - Section 6 Practice Tasks Task One: Odd Numbers Use a for loop to print all odd numbers between 50 and 70 . You will need to use three values in the range brackets, including a step . Requirements for full marks: A comment at the start to explain what a for loop is. Use just two lines of code. Example solution: 51 53 55 57 59 61 63 65 67 69 Task Two: Fish Rhyme Use two separate for loops and some additional print lines to output this nursery rhyme: "1, 2, 3, 4, 5, Once I caught a fish alive, 6, 7, 8, 9, 10 then I let it go again" in the format shown . Requirements for full marks: Two for loops and two additional print lines (6 lines total). Example solution: 1 2 3 4 5 Once I caught a fish alive. 6 7 8 9 10 Then I let it go again. Task Three: Username & Password Create a program using a while loop that keeps asking a user to enter a username and a password until they are both correct . It may be easier to use a while True loop . You will need to use the and command in an if statement within the loop. Requirements for full marks: A comment at the start to explain what a while loop is. Example solution: Enter username: Ben43 Enter password: hamster Incorrect, please try again. Enter username: Ben44 Enter password: ben123 Incorrect, please try again. Enter username: Ben43 Enter password: ben123 Correct Correct login. Welcome Ben43 Task Four: Colour or Number Use a while True loop to let the user enter either A , B or C . A lets them guess a secret colour . B lets them guess a secret number . C breaks the loop , ending the program. Example solution: Enter A to guess a colour, B to guess a number, C to quit: A Guess the colour: green Incorrect! Enter A to guess a colour, B to guess a number, C to quit: A Guess the colour: pink Correct! Enter A to guess a colour, B to guess a number, C to quit: B Guess the number: 4 Incorrect! Enter A to guess a colour, B to guess a number, C to quit: C Quitting program... ⬅ 6b - W hile Loops 7a - Procedures ➡

Learn how to use if statements in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 4a - If Statements If Statements Selection is one of three constructs of programming , along with Sequence (logical order) and Iteration (loops). An if statement is a conditional statement that performs a specific action based on conditional values. Essentially, if thing A is true , then thing B will happen . If the user answers yes to the window question, then an appropriate statement is printed. Double equals stands for ‘is equal to ‘. The colon stands for THEN and the line after an if statement must be indented (press tab key once). answer = input ( "Is the window open? " ) if answer == "yes" : print ( "It's chilly in here!" ) Is the window open? yes It's chilly in here! But what if the window is not open? At the moment nothing will happen if you type no: Is the window open? no The elif command stands for else if . Essentially: If thing A is true then do thing B, else if thing C is true then do thing D: But what about any other answer than yes or no? The else command will submit a response if the value is anything else. The if and elif commands have a colon at the end, but else has it at the start. Also, else does not need to be on a new line. answer = input ( "Is the window open? " ) if answer == "yes" : print ( "It's chilly in here!" ) elif answer == "no" : print ( "It's quite hot in here!" ) answer = input ( "Is the window open? " ) if answer == "yes" : print ( "It's chilly in here!" ) elif answer == "no" : print ( "It's quite hot in here!" ) else : print ( "I'm not sure what you mean." ) Is the window open? no It's quite hot in here! Is the window open? banana I'm not sure what you mean. If Statements Task 1 ( Left or Right?) Use an input line to ask the user whether they want to turn left or right . Print a sentence of your choice if they chose left and a different sentence if they chose right . Include an else statement in case the user doesn't input left or right. Example solutions: There is a path ahead. Do you turn left or right? left The path turns and twists until it reaches a cliff. Dead end! There is a path ahead. Do you turn left or right? right A snake slithers across the path and bites your leg. Oh no! There is a path ahead. Do you turn left or right? backwards That's not an option! Nested If Statements Complex programs may require you to have if statements within if statements - when programming, one thing inside another is known as nesting . You must make sure that the related if , elif and else statements line up with each other . Use the tab key to indent a line. outer if inner if weather = input ( "What is the weather like today? " ) if weather == "sunny" : sunny = input ( "How hot is it? " ) if sunny == "very hot" : print ( "Take some sunglasses with you!" ) elif sunny == "cool" : print ( "Maybe take a jacket just in case?" ) else : print ( "Enjoy the sunshine!" ) elif weather == "rainy" : print ( "Take an umbrella!" ) else : print ( "Have a good day!" ) = What is the weather like today? rainy Take an umbrella! = What is the weather like today? sunny How hot is it? cool Maybe take a jacket just in case? = What is the weather like today? snowy Have a good day! = What is the weather like today? sunny How hot is it? very hot Take some sunglasses with you! If Statements Task 2 ( Nested Ifs) Use the weather program above as an example to help you write your own program with a nested if for at least one option. Be careful to have your nested if's if, elif and else statements in line with each other. Your program doesn't have to be about juice. Example solutions: Would you like orange, apple or tomato juice? orange Would you like your orange juice smooth or with bits? smooth One smooth orange juice coming up! Would you like orange, apple or tomato juice? orange Would you like your orange juice smooth or with bits? bits A pulpy orange juice is on its way! Would you like orange, apple or tomato juice? tomato Yuck, you can't be serious? Using Selection with Numbers Comparison operators such as > (greater than ) > = (greater than or equal to ) < (less than ) and < = (less than or equal to ) can be used with if statements. Logical operators such as and and or can also be used - more about them in section 4c . When comparing a variable's value to a specific number, such as 50, don't forget to use double equals ( == ) . Python Comparison Operators score = int ( input ( "Enter the maths test score: " )) if score == 50: print ( "You scored top marks!" ) elif score >= 40 and score < 50: print ( "You scored a great grade!" ) elif score >= 20 and score < 40: print ( "You did okay in the test." ) else : print ( "You have to try harder next time!" ) = Enter the maths test score: 50 You scored top marks! = Enter the maths test score: 43 You scored a great grade! = Enter the maths test score: 20 You did okay in the test. = Enter the maths test score: 13 You have to try harder next time! If Statements Task 3 ( Fastest lap) A racing video game has a challenging track that players try to get a quick lap on. The current fastest lap time is 37 seconds . Ask the player to enter their lap time and print a response based on their input . You need individual responses for the following inputs: Faster than 37 seconds. Between 37 seconds and 59 seconds. Between 60 seconds and 90 seconds. Slower than 90 seconds. Example solutions: Enter your lap time: 35 You have set a new record!!! Enter your lap time: 59 You did well this time! Enter your lap time: 83 A little bit slow this time! Enter your lap time: 110 Were you even trying!?! Hurry up! Not Equal To The opposite of equal to ( == ) is not equal to ( != ). != is often used with while loops to repeat code while an input is not what is expected , for example repeatedly asking for a password while the input is not equal to "fluffythecat123". The code below uses != for an incorrect answer (although it could easily be re-written to use == for a correct answer). answer = input ( "What is the capital of Eritrea? " ) if answer != "Asmara" : print ( "That is incorrect! It is Asmara." ) else : print ( "You got it right!" ) = What is the capital of Eritrea? Asmara You got it right! = What is the capital of Eritrea? Windhoek That is incorrect! It is Asmara. If Statements Task 4 ( True or False? ) Come up with your own true or false question that the user has to respond to. Depending on their answer , print whether they got it right or wrong . You may want to use an if statement with == for a correct answer or != for an incorrect answer , there's multiple ways to write this program. Example solutions: There are 140 million miles between Earth and Mars. TRUE or FALSE? TRUE That is correct! It is really that far! There are 140 million miles between Earth and Mars. TRUE or FALSE? FALSE You got it wrong, there really are 140 million miles between us! ⬅ Section 3 Practice Tasks 4b - Mathematical Operators ➡