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Learn about how sounds are represented in a computer system including how analogue sound waves are converted into binary. Also, learn about sample rate, bit depth, bit rate and metadata. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 2.4e: Sound Storage Exam Board: OCR Specification: J277 Watch on YouTube : Sample Rate Bit Depth Sound File Size Converting Analogue Sound to Binary Analogue sound waves must be digitally recorded and stored in binary . To record the sound, the amplitude (height ) of the analogue sound wave is measured and recorded in binary at specific intervals . 0010 1011 0101 0101 Analog sound wave ADC (Analog to Digital Converter) Binary sample Sampling an Analogue Sound Wave Digital sampling is discrete (separate) and not continuous like analogue waves. To get the highest quality sound, many samples are taken to recreate the analogue wave as closely as possible . Sample Rate The sample rate (sampling frequency) is the number of times per second the amplitude of the sound wave is measured . It is measured in kilohertz (kHz), for example CD quality is 44.1kHz (44,100 samples per second). The higher the sample rate , the better the audio quality as the digital data more closely resembles an analogue wave . However, higher sample rates result in larger file sizes because more data is stored for each individual sample. A low sample rate will result in a low-quality sound because the digital data does not closely resemble the original analog wave . A higher sample rate will result in a higher-quality sound because the digital data more closely resembles the original analog wave . Bit Depth The bit depth is the number of bits available to represent each sample . For example, a sample with a bit depth of 4 could be 0101 or 0111 or 1010. A sample with a bit depth of 8 could be 01010110 or 1010110 or 11001111. A common bit depth is 16 bits . The higher the bit depth , the more bits are available to be used for each sample. Therefore the quality is often higher as the wave more closely resembles an analog wave . The file size will also be larger if the bit depth is higher, as each sample stores additional bits . low bit rate = lower quality high bit rate = higher quality sound file size = sample rate x bit depth x duration Example: A short audio sample has a bit depth of 4 and a sample rate of 10 samples per second . The clip is 15 seconds long . 4 bits x 10 = 40 bits per second. 40 x 15 = 600 bits . To convert the answer from bits to bytes , divide by 8 . 600 bits ÷ 8 = 75 bytes . Calculating File Size Q uesto's Q uestions 2.4e - Sound Storage: 1. Explain how an analogue sound wave is converted into a binary sample . [ 2 ] 2a. What is a sample rate ? [2 ] 2b. Explain two ways an audio file will be affected if the sample rate is increased . [4 ] 3a. What is bit depth ? [2 ] 3b. Explain two ways an audio file will be affected if the bit depth is increased . [4 ] 4 . An audio sample has a bit depth of 8 , a sample rate of 10 and it is 12 seconds long . What is the file size in bytes ? [ 2 ] 2.4d Image Storage Theory Topics 2.5 - Compression

Learn about application software installation methods, including clean, remote, cloud, mobile and network installation. 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 5.2 - Application Software Installation Watch on YouTube : Application installation You need to know how different installation processes (e.g. clean , remote , cloud , network and mobile installs) work as well as their advantages , disadvantages and appropriate uses . What You Need to Know Application Installation ? YouTube video uploading soon Q uesto's Q uestions 5.2 - Application Software Installation: 1. What? [2 ] 2. What? [1 ] 3. What? [1 ] 4. What? [1 ] ? D id Y ou K now? 5.1 - Testing Topic List 5.3 - Policies

Learn about Application Programming Interfaces (APIs), including their roles, types (composite, internal, private, public, partner) and architecture (REST, SOAP, RPC). 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 3.1 - Application Programming Interface (API) Watch on YouTube : API roles API architecture You must know the role and uses of Application Programming Interfaces (APIs ) as well as the uses , advantages and disadvantages of each API type (composite , internal , private , public , partner ). You must also understand the uses , advantages and disadvantages of API architecture (REST , SOAP , RPC ). What You Need to Know API Roles ? YouTube video uploading soon API Architecture ? YouTube video uploading soon Q uesto's Q uestions 3.1 - Application Programming Interface (API): 1. What? [2 ] 2. What? [1 ] 3. What? [1 ] 4. What? [1 ] ? D id Y ou K now? 2.3 - Data States Topic List 3.2 - Protocols

Learn about the tools of an integrated development environment (IDE) including the editor, debugger, library, trace, memory inspector and error diagnostics. Based on the 2020 Eduqas (WJEC) GCSE specification. 9.1: IDE Tools Exam Board: Eduqas Specification: 2020 An IDE (Integrated Development Environment ) provides programmers with the following facilities (tools ) to help create programs : Editor The editor is software that allows a programmer to enter and edit source code . Editor features may include: Automatic formatting (e.g. automatic indentation). Automatic line numbering (this helps to identify exactly where an error has occurred). Automatic colour coding (e.g. Python turns loop commands orange and print commands purple). Statement completion (e.g. offering to auto-complete a command as the user is typing.) Libraries A library is a collection of commonly used functions and subprograms that can be linked to a program . For example, Python can import functions from its code library including random or time commands). Libraries must be linked to the main program using a linker . Linker Links together pre-compiled code from software libraries . For example, the import random command in Python links to the random library. Loader Pre-compiled code is loaded into RAM to be executed. Code Optimisation The code is optimised so it is fast , efficient and uses as little of the computer's resources as possible. Debugger Identifies errors in the code with the exact line of the error to help fix the problem . Break point The programmer selects a specific line and the program is paused once it reaches it. Variable values at that point are shown . Variable Watch cost Displays the current value of a selected variable . A variable can be watched line-by-line to see how the value changes . Trace Memory Inspector Logs the values of variables and outputs of the program a s the code is executed line by line . Displays the contents of a section of memory and how it is being used by the program . Error Diagnostics Displays information about an error when it occurs, such as the line it occurred on and the error type (e.g. syntax or runtime). This helps the programmer to fix the error . Specific errors can be detected such as a syntax error . See 10.3 . Compilers & Interpreters Both tools convert the source code written by a programmer into machine code to be executed by the CPU. A compiler converts the entire source code into executable machine code at once . After compilation, the program can be run again without having to recompile each time. An interpreter converts source code into machine code line by line . An interpreter must reinterpret the code each time the program is required to run . See 10.1 for both tools. Subroutines & Functions A subroutine is a section of code that can be re-used several times in the same program. There are two types of subroutines: A procedure just executes commands , such as printing something a certain number of times. A function can receive data from the main program (called a parameter ) and return a value upon completion. Subroutines (procedures and functions) are designed to be repeated and have three key benefits: Subroutines make programs easier to read and design . They reduce the duplication of code . Makes it is easier to debug a program. Q uesto's Q uestions 9.1 - IDE Tools: 1. Describe the purpose of each type of IDE facility : a. Editor b. Interpreter c. Compiler d. Linker e. Loader f. Debugger g. Break point h. Variable Watch i. Trace j. Memory Inspector k. Error Diagnostics [ 2 each ] 8.5 - Validation & Verification Theory Topics 10.1 - Translators

Learn about the five main roles of an operating system including CPU management, security, managing processes and the user interface. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 5.1: Operating Systems Exam Board: OCR Specification: J277 Watch on YouTube : Operating Systems What is an Operating System? An operating system (OS ) is software that helps to manage the resources of a computer system and provide the interface between the user and the computer’s hardware . There are five main functions of an operating system: Memory Management & Multitasking All programs must be temporarily stored in RAM for the CPU to be able to process them. The OS transfers programs in and out of memory from the hard drive (or virtual memory ) when processing is required - programs are removed from RAM when closed to free up space for other tasks. The operating system can only perform one process at a time , but through memory management it can appear that more than one process is being executed - this is called multitasking . Peripherals Management & Drivers A peripheral is an external device connected to a computer system to input or output data . Data is transferred between external devices and the processor and this process needs to be managed by the operating system . A device driver is a program that provides an interface for the OS to interact and communicate with an external device . Drivers are hardware dependent and OS-specific . The driver translates the OS’ instructions into a format the specific hardware can understand . Because the CPU and the peripheral will process data at different speeds , a buffer is typically used to temporarily store data until it can be processed . User Management The OS allows users to create , manage and delete individual accounts . User accounts can be granted different access rights such as an administrator or guest . The OS will manage security settings such as allowing passwords to be reset and can also be used to monitor login activity . File Management The operating system creates and maintains a logical management system to organise files and directories (folders ). File management allows files to be named , renamed , opened , copied , moved , saved , searched for , sorted and deleted . It also allows users to set access rights for specific files and to view file properties . User Interface The final function of an operating system is to provide a user interface , allowing a human to interact with the computer system . The way in which a user can navigate a computer system is known as human-computer interaction ( HCI ). Graphical User Interface (GUI) The most common type of user interface is a graphical user interface (GUI ) which can be presented in the following ways: Icons are displayed to represent shortcuts to applications and files. Multiple windows can be opened at the same time and switched between. A folder and file system is displayed and manipulated allowing for copying , searching , sorting and deleting data. The interface can be customised , such as changing font sizes and the desktop background . The taskbar allows shortcuts to be pinned for quick access . Menus can be opened from the Start button to display files and shortcuts. System settings can be accessed such as network and hardware options . Command-Line Interface Other types of user interface do exist, such as a command-line interface (CLI ). This type of interface is entirely text-based and requires users to interact with the system by typing commands . This is a complicated process and mistakes could easily accidentally delete data. There are many commands to learn so only experts who have been trained t o learn this interface will be able to efficiently make use of it. Other Interfaces Humans can interact with computers using other types of interface , such as: Touch-sensitive interface (e.g. smartphones ). Voice-sensitive interface (e.g. smart speakers ). Menu-driven interface (e.g. ATMs in banks). Q uesto's Q uestions 5.1 - Operating Systems: 1. Describe each role of the operating system : Providing a user interface [ 3 ] Memory management (and multitasking) [ 3 ] Peripheral management (and drivers) [ 3 ] User management [ 3 ] File management [ 3 ] 2. Describe 5 different ways the operating system can provide a graphical user interface (GUI) . [5 ] 4.2 - Preventing Vulnerabilities Theory Topics 5.2 - Utility Software

Test your understanding of subroutines (procedures and functions) in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python - Section 7 Practice Tasks Task One Example solution: Create a program with three different subroutines (procedures ). One subroutine asks the user their name and prints a response. The second asks for their age and prints a response. The third asks for their favourite colour and prints a response. Remember to write subroutines before the main program. Task Two Create a program that asks a user to input the length of a side in a square. Write a function that takes this value and returns it to be printed. Example solution: Task Three Example solution: Create a program that takes 3 inputs from the user – a name, a villain and a place. Write a function that outputs a story using the user’s answers. Task Four Create a calculator program that uses four different subroutines (add, subtract, multiply and divide). In the main program ask the user to make a choice of which operator to use and then to enter two numbers. Keep looping until the user types stop. Use the 'Using Subroutines as a Menu' section in the 7b to help you. Example solution: ⬅ 7b - Functions 8a - Using Lists ➡

Test your ability to create a more complex program in Python based on a given scenario. Perfect for students learning GCSE Computer Science in UK schools. Extended Task 3 Hi, Susanna here, I want to make a blackjack-like program that I can play for fun at home in between revising for Computer Science. The aim of my blackjack game is to get as close to 21 as possible with the most number of cards, without going over. So... The user can choose whether to be hit with a new card (a number between 1 and 8) or fold and stop. Each number they are dealt adds up to their total . If the total goes over 21, then they lose . If they bust (when over 21) or folded then their final number and their number of cards is displayed . Blackjack For this task, you will need to create a document and include the following sections (with screenshots where appropriate): An introduction to explain the Purpose of your program . A List of Requirements for a successful program. Screenshots of your code (with comments in your code to show understanding). Testing – Create a plan to show how you will test your program and then explanations of any errors that you found and how they were fixed . An Evaluation of what worked, what didn’t, and how you met each of your requirements from your original list. Also, discuss further improvements that you could have made to improve your program. Example solution: Helpful reminders for this task: Think about the type of loop that you need. Will you need more than one loop? What variables will you need? Remember to use an input . What will you ask the user? How will you use their response? Remember to use ‘import random’ and randint to create a random number . What outputs do you need and when? What should you display… After each hand? At the beginning? At the end? ⬅ Extended Task 2 (Lottery) Extended Task 4 (Vet Surgery) ➡

Test your ability to create a more complex program in Python based on a given scenario. Perfect for students learning GCSE Computer Science in UK schools. Extended Task 2 Lottery 17 8 4 13 20 Create a program to simulate a lottery draw. First, create an appropriate print line to welcome the user to your lottery draw. Then let the user enter five numbers between 1 and 20. Next, randomise five numbers between 1 and 20. Check to see how many numbers match and output an appropriate response for each scenario (e.g. “You have not matched any numbers, better luck next time!”) Once you have made the base program implement subroutines and lists . Make it as efficient as possible and professional-looking. Use pauses to reveal each number one at a time like a real lottery draw to build suspense. For this task, you will need to create a document and include the following sections (with screenshots where appropriate): An introduction to explain the Purpose of your program . A List of Requirements for a successful program. Screenshots of your code (with comments in your code to show understanding). Testing – Create a plan to show how you will test your program and then explanations of any errors that you found and how they were fixed . An Evaluation of what worked, what didn’t, and how you met each of your requirements from your original list. Also, discuss further improvements that you could have made to improve your program. Example solution: Helpful reminders for this task: Inputting Numbers Random Numbers Logical Operators Subroutines ⬅ Extended Task 1 (Pork Pies) Extended Task 3 (Blackjack) ➡

Learn about different types of tools used in the data analysis process including data visualisation, data cleaning and GIS. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 3.5 - Data Analysis Tools Exam Board: OCR Specification: 2016 - Unit 2 The fifth stage of data analysis is to select the most appropriate tools to analyse the collected data. The method(s) selected will depend on the type of project and the established objectives. Data Tables Databases are often split into tables to be easier to update , view and manipulate . For example, a supermarket database may include a table of product information, another table of suppliers and another for actual stock levels. Separating the data into tables allows for simpler editing and also allows for the display of basic patterns . For example, looking at a table of stock levels in a supermarket can quickly show which products need to be ordered in as they are close to selling out. Data tables allow for the most simple form of pattern discovery and are a good method of speedy, short-term data analysis . However they present data in its current format and cannot show change or trends over time - a product may have a high stock level because it is popular and has just been ordered in, rather than because no-one is buying it. A simplified data table for a supermarket. Visualisation of Data Visualising data (by producing a chart or graph of collected data for example) makes it easier for an audience to see trends and patterns . Visualising data, like the bar chart to the right of the supermarket table from the tool above, makes it easier to understand and quicker to interpret . In this example, It is easier to see using the chart that steak pies are low in stock and should be re-ordered soon. A bar chart of the supermarket data table. Trend & Pattern Identification This tool links heavily to visualisation of data in allowing trends and patterns to be viewed as a visual format - such as producing a line graph of last year’s stock sales. Statistical analysis allows data analysts to examine numerical data and, if done correctly, can highlight relationships between different data elements - such as the price of a product and how many have been sold. Discovering links between variables is known as regression analysis . Data Cleaning Data cleaning ensures that any stored data is up-to-date and accurate , in accordance with the Data Protection Act ( 2018 ). Forms of data cleaning include removing customers who have not made a purchase in a certain amount of time (e.g. two years) and periodically checking that user addresses are up to date. Data cleaning would reduce the size of any data table by removing redundant, incorrect or unnecessary data . This would make it easier to work with the data table and would improve the data quality by removing erroneous and irrelevant data. GIS / Location Mapping Geographic Information Systems (GIS ) can be used to add geographic data to any analysis. For example, an organisation can track the geographical location of items or staff e.g. tracking the movement of shipping containers around the world to see production flow. This also works for courier services to see delays and delivery times in real-time . Q uesto's Q uestions 3.5 - Data Analysis Tools: 1. Describe how Fresh Food UK, from the question in 3.4 , could use each of the data analysis tools when trying to determine and present the most profitable stores across the country in the past year . a. Data Tables [3 ] b. Visualisation of Data [3 ] c. Trend & Pattern Identification [3 ] d. Data Cleaning [3 ] e. GIS / Location Mapping [3 ] 3.4 - Stages of Data Analysis Topic List 3.6 - Information Systems

Learn how to use mathematical operators in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 4b - Mathematical Operators Modulo Division The modulo operator - the percentage symbol % - will work out the remainder left over when one value is divided by another. print (30 % 6) = 0 30 ÷ 6 = 5, which is a whole number, so there is no remainder and 0 is output . print (30 % 7) = 2 30 ÷ 7 = 4 remainder 2 ; so the remainder is output . You can use modulo with variables too: num1 = 33 num2 = 4 print ( "The remainder is" , num1 % num2) The remainder is 1 = A common use of modulo is to check if a number is odd or even . If a number has no remainder when divided by 2 then it is even . = num = int ( input ( "Enter a number: " )) if num % 2 == 0: print (num, "is even." ) else : print (num , "is odd." ) Enter a number: 400 400 is even. Enter a number: 191 191 is odd. = Modulo Div i sion Task 1 ( Remainder) Ask the user to input a whole number . Use the modulo operator ( % ) to check if there is a remainder when the user's number is divided by 5 . Print the re mainder. Example solution: Enter a number: 123 The remainder when divided by 5 is 3 Modulo Div i sion Task 2 ( Rollercoaster) Use the odd/even program above to help solve this problem: A rollercoaster only lets people on in groups of 4 . Ask the user to input a number for how many people are in their group. Check if that number is directly divisible by 4 using modulo division ( % ). If it is then print “Perfect groups of four!” Else print “You will be split up” . Example solutions: Welcome to the Hyper Coaster! How many in your group? 6 You will be split up! Welcome to the Hyper Coaster! How many in your group? 12 Perfect groups of four! Integer Division Integer division removes any decimal numbers when performing division , leaving just the integer (whole number ). In Python integer division is performed using // . print (20 / 3) print (20 // 3) = 6.666666666666667 6 Integer Div i sion Task 1 ( Integer Division by 5 ) Use an input line with int to ask the user to enter a number . Use integer division ( // ) to divide the number by 5 without keeping any decimal values . Challenge: Improve your solution by altering the print line to be more user friendly . Example solutions: Enter a number: 27 5 Enter a number: 27 5 goes into 27 5 times. Integer Div i sion Task 2 ( Plane Rows) A large plane has 6 seats in each row. Input the number of passengers on the plane and use integer division to work out how many full rows will be filled. Example solution: How many passengers are there in total? 174 There will be 29 full rows on the plane. Exponent (Powers) An exponent is the number of times a value is multiplied by itself , for example 2 = 2 x 2 x 2 = 8 . The symbol to represent an exponent in Python is ** . For example: 4**2 represents 4 which is also 4 x 4 . 3 2 print (4**4) = 256 base = 5 exponent = 4 print (base**exponent) 625 = Exponent Task 1 ( Square Number) Use an input line with int to ask the user to enter a number . Output the square of this number. Example solution: Enter a number: 12 12 squared is 144 Exponent Task 2 ( Custom Exponent) Use an input line with int to ask the user to enter a number, this will be the base . Make another input line with int to ask for the exponent . Use ** between the base and the exponent and print it. Challenge: Make your solution better by including the base and exponent in the print line. Example solutions: Enter the base: 7 Enter the exponent: 3 343 Enter the base: 7 Enter the exponent: 3 7 to the power of 3 is 343 ⬅ 4a - If Statements 4 c - Log ical Operators ➡

Learn about the decomposition methods used in project planning such as abstraction, pattern recognition, modularisation (top down and bottom up) and parsing of requirements. 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) 4.3 - Decomposition Methods Watch on YouTube : Abstraction Pattern Recognition Modularisation Parsing of Requirements Decomposition methods break complex problems or systems into smaller , more manageable parts . This makes development easier to plan , understand and implement . Decomposition also helps reduce errors and improve efficiency , as individual tasks can be more easily tested and debugged. For each of the four decomposition methods ( abstraction , pattern recognition , top-down and bottom-up modularisation and parsing requirements ) you need to know when each method is suitable to use , its advantages and disadvantages , how client requirements affect their selection and how they can be used to visualise application designs . Decomposition Methods Abstraction Abstraction is the process of simplifying a problem by ignoring irrelevant data and focusing only on the most important details . It is used in the early stages of design or planning , when managing complexity in large systems and when creating reusable components . Pattern Recognition Pattern recognition is used to identify similarities or trends in problems or client requirements . This allows for the reuse of existing components and aids in finding solutions for common issues . It is used during the planning or analysis phases and when dealing with similar tasks , inputs , outputs or processes . Modularisation Modularisation refers to the individual components that make up a larger project . In top-down modularisation , a larger system is broken down from a general overview into its most specific parts . The purpose of bottom-up modularisation is to build the system starting with the smaller , detailed components and combining them into larger subsystems . Parsing of Requirements To parse requirements means to systematically break down and analyse client requirements into actionable tasks or functions . It is used at the start of a project to ensure shared understanding between development teams and clients . Q uesto's Q uestions 4.3 - Decomposition Methods: 1. Explain the differences between top-down and bottom-up modularisation . [4 ] 2. Explain when abstraction would be an appropriate decomposition method to use. [3 ] 3. What are the advantages and disadvantages of parsing requirements ? [ 4 ] 4. Give one way each decomposition method can be used in software application development . [ 4 ] Alan Turing and his team used pattern recognition to analyse recurring sequences in encrypted German messages , helping to break the Enigma code , which was a major factor in the Allies’ victory in World War II . D id Y ou K now? 4.2 - Client Requirement Specs Topic List 5.1.1 - Human-Computer Interaction

Learn how to delay processes using the sleep command in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 5b - Sleep Using Sleep To pause a program, import sleep from the time library . Type the word sleep followed by the number of seconds that you wish the program to break for in brackets . It must be a whole number . Below is an example of a program that imports the sleep command and waits for 2 seconds between printing: from time import sleep print ( "Hello!" ) sleep(2) print ( "Goodbye!" ) You can implement the sleep command within a for loop to produce an effective timer that outputs each second waited to the screen: You could also use a variable instead of a fixed value with the sleep command such as below: from time import sleep for second in range (1,11): print (second) sleep(1) from time import sleep seconds = int ( input ( "How many seconds should I sleep? " )) print ( "Going to sleep..." ) sleep(seconds) print ( "Waking up!" ) Sleep Task ( Slow Calculator) Create a slow calculator program that needs time to think in between calculations. Print a message to greet the user , then wait 3 seconds and ask them to enter a number . Wait another 3 seconds and ask them to enter a second number . Wait 2 more seconds , print “Thinking…” then 2 seconds later print the total of the two numbers added together . Example solution: ⬅ 5a - Rando m 5c - Date & Time ➡