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5.2: Utility Software What is utility software? Utility software are dedicated programs used for the maintenance and organisation of a computer system. ​ Anti-malware (such as an anti-virus or anti-spyware ), firewall and encryption software are examples of utilities and have been explained in section 4.2 . ​ Data Compression is another utility that has been explained in section 2.5 . ​ Other utility software include backup software , disk checkers , disk formatters and auto-updaters . Exam Board: OCR Specification: 2020 Defragmentation What is fragmentation and how does it happen? Over time files stored on a hard disk drive may become fragmented - this is when the file is split into parts that are saved in different storage locations . Fragmentation occurs when there is limited contiguous space in which to store a file . This may happen as data is stored and then later deleted on the hard drive . New files are created which may be bigger than the spaces left by the deleted files . The new files are then split up . Fragmentation increases access time - files that are fragmented take longer to load and read because of the distance between the fragments of the file. How does defragmentation work? Empty spaces are collected together on the hard disk drive and file fragments are moved to be stored together. ​ This means that fewer disc accesses are needed (requiring less physical movement ) as file fragments can be read consecutively . What are the effects of defragmentation? A defragmented file takes less time to read and access because the data is stored contiguously . The read/write head of the hard drive does not need to move as far to read the next piece of data because it is in the adjacent memory location , saving time . It also quicker to save new files because there is more free space together so it does not need to split the file and can store the data contiguously . Q uesto's Q uestions 5.2 - Utility Software: ​ 1. Explain what fragmentation is and how a file may become fragmented . [ 3 ] 2. Describe the process of defragmentation . [ 3 ] 3. Explain the effects of defragmenting a hard disk drive. [ 3 ] 5.1 - Operating Systems Theory Topics 6.1a - Impacts of Technology

top Python 9a - String Handling What is String Handling? String handling refers to the manipulation of a string variable , typical uses include: ​ Checking the length of a variable. Searching a variable for a certain phrase. Checking the number of times a specific character or word is used . ​ String handling is used to examine passwords and to ensure that they are of an acceptable strength (e.g. by checking that they are at least 8 characters in length and include a mixture of capital letters , lowercase letters and symbols ). Password: arsenal Password: $tr0nG_pA$$w0rd Lowercase & Uppercase .lower() and .upper() are functions that convert a string into a fully lowercase or uppercase version. dogbreed = "Chihuahua" print (dogbreed.upper()) CHIHUAHUA character = "sPoNgeBoB" print (character.lower()) spongebob You may have realised that Python is very specific . 'yes ', 'Yes ' and 'YES ' are all treated as different values . ​ Converting user input into one case , such as lowercase, and then comparing that input is a better way of checking an input than having an if statement with multiple or comparisons. The program below converts the user input into lowercase to compare. 'yes', 'Yes' and 'YES' are all converted to 'yes'. answer = input ( "Would you like water? " ) answer = answer.lower() if answer == "yes" : print ( "I'll fetch you a glass." ) else : print ( "Don't dehydrate!" ) Would you like water? yes I'll fetch you a glass. Would you like water? Yes I'll fetch you a glass. Would you like water? YES I'll fetch you a glass. Practice Task 1 Ask the user to enter their first name and surname. Print their surname in uppercase followed by their first name in lowercase. Example solution: Enter First Name: Jayden Enter Surname: Hargrove Welcome HARGROVE, jayden Count Characters The easiest way to count how many times a certain value appears within a string is to use the .count() command. It is important to note that, just like when using an input statement or calculation line, you must save the calculation into a variable . An example, for counting the number of e’s in a sentence, is below: sentence = input ( "Enter your sentence: " ) e_count = sentence.count( "e" ) print ( "There were" , e_count, "e's in your sentence!" ) Enter your sentence: even ellie eats elderberries There were 9 e's in your sentence! Practice Task 2 Create a program that counts how many instances of the letter a have been entered in a sentence. Bonus: Use the .lower() function in your code to include capital letters. Example solution: Enter a sentence: An angry aardvark named Aaron. That sentence had 8 a's. Finding the Length of a String Just like when we wanted to find the length of a list, we use the len command to see how many characters are in a string . It is sensible to save the result of the function into a variable so it can be used later . fruit = input ( "Enter a fruit: " ) length = len (fruit) print ( "That fruit was" , length, "characters." ) Enter a fruit: pineapple That fruit was 9 characters. A common reason for finding the length is as part of validation , for example, checking a password is more than 8 characters : password = input ( "Enter a new password: " ) length = len (password) if length >= 8: print ( "Password accepted!" ) else : print ( "Password is too short, must be at least 8 characters." ) Enter a password: snake54 Password is too short, must be at least 8 characters. Enter a password: pebblesthedog76 Password accepted! Practice Task 3 Create a program that asks for a name. Check that the name is between 4 and 10 characters. Print appropriate messages if it is within this range and if it isn't. Example solution: Enter a name: Tom That name is too short, it must be between 4 and 10 characters. Checking the Start / End of a String To determine if the first character in a string is a specific value use the .startswith() command. ​ .startswith() is a function that will return True or False . ​ Below is an example program to check if a name begins with the letter L . name = input ( "Enter a name: " ) if name.startswith( "L" ) == True : print ( "I like that name." ) else : print ( "I don't like that name." ) Enter a name: Lionel I like that name. Enter a name: Katjaa I don't like that name. Similarly, you can use .endswith() to check the last characters of a string . Practice Task 4 Ask the user to enter a country. Print a message if it ends with 'land', 'stan' or any other ending. Use .endswith() Example solution: Enter a country: Finland You have entered a 'land' country. There are 9 in the world. Enter a country: Kyrgyzstan You have entered a 'stan' country. There are 7 in the world. Enter a country: Peru Thanks for your entry. Note: You don't need to check if it's a valid country. Reversing a String To reverse a string, you write the variable name and then use square brackets to move one character at a time backwards. The first two colons are left empty as they denote where to start and end from (which don’t need to be changed). ​ Therefore the -1 states that it will reverse from the end to the start : Ask the user to enter a random sentence. ​ Print the sentence in reverse. Example solution: Practice Task 5 Printing Parts of a String You may want to print just part of a string or variable using square brackets. You can also use len to work out the length and work back, if you want to display the last characters: Practice Task 6 Ask the user to input a long word. ​ Output the middle character of the word. Example solution: Split Strings Use the .split command to split a string into separate words . ​ An empty split command such as words.split() will split at each space . You can enter a value in the brackets to split at certain characters , such as words.split(",") Use the len function to count the number of words once they have been split. You can use a for loop to cycle through each word. The program below checks the length of each word . Practice Task 7 Ask the user to input a sentence. ​ Calculate and print the amount of words in the sentence. ​ Calculate and print the amount of words that begin with s. Example solution: ⬅ Section 8 Practice Tasks 9b - Number Handling ➡

1.1b: Registers & The F-E Cycle Exam Board: OCR Specification: 2020 The Fetch - Execute (F - E) cycle is performed by the CPU millions of times every second. ​ This cycle is how the CPU processes data and instructions for each program or service that requires its attention. Important Registers A register is a small storage space for temporary data in the CPU . Each register has a specific role . There are three essential registers used in the F-E cycle : ​ Program Counter (PC) A register that tracks the RAM address of the next instruction to be fetched . Memory Address Register (MAR) ​ A register that tracks the RAM address of the instruction that is to be fetched . Memory Data Register (MDR) ​ The MDR stores the instruction that has been transferred from RAM to the CPU . Current Instruction Register (CIR) A register that stores the instruction that has been fetched from RAM , and is about to be decoded or executed . Accumulator (ACC) ​ The ACC stores the result of mathematical or logical calculations . Fetch - Execute Cycle The essential idea of the F-E cycle is that instructions are fetched from RAM , to be decoded (understood) and executed (processed) by the CPU . 1. The Program Counter (PC ) register displays the address in RAM of the next instruction to be processed . This value is copied into the Memory Address Register (MAR ). 0054 2. The PC register is increased by 1 . ​ This prepares the CPU for the next instruction to be fetched. 0055 3. The CPU checks the address in RAM which matches the address held in the MAR . 0054 4. The instruction in RAM is transferred to the Memory Data Register (MDR ). 5. The instruction in the MDR is copied into the Current Instruction Register (CIR ). MDR MDR CIR 6. The instruction in the CIR is decoded (understood) and executed (processed). Any result of an execution is stored in the Accumulator (ACC ) register. CIR ACC 7. The cycle repeats by returning to the first step and checking the program counter for the address of the next instruction . Q uesto's Q uestions 1.1b - Registers & The F-E Cycle: ​ 1 . What is the purpose of the registers ? [1 ] ​ 2 . Describe the purpose of each register : a. The Program Counter (PC) [ 2 ] b. The Memory Address Register (MAR) [ 2 ] c. The Memory Data Register (MDR) [ 2 ] d. The Current Instruction Register (CIR) [ 2 ] e. The Accumulator (ACC) [ 2 ] ​ 3. Draw a diagram with icons and words to show the steps of the Fetch - Execute cycle . [7 ] 1.1a - The CPU Theory Topics 1.2 - CPU Performance

2.2: Secondary Storage Exam Board: OCR Specification: 2020 Secondary storage is non-volatile storage used to save and store data that can be accessed repeatedly. ​ ​ Secondary storage is not directly embedded on the motherboard (and possibly even external ) and therefore further away from the CPU so it is slower to access then primary storage . Storage Characteristics you should know: ​ CAPACITY : The maximum amount of data that can be stored on the device. DURABILITY : The strength of the device, to last without breaking. PORTABILITY : How easy it is to carry the device around. ACCESS SPEED : How quickly data on the device can be read or edited. COST : The average price it costs to purchase a storage device. ​ RELIABILITY : The likelihood of the device continuing to perform well over time. Magnetic Storage A magnetic hard disk drive (HDD ) is the most common form of secondary storage within desktop computers. A read/write head moves nanometres above the disk platter and uses the magnetic field of the platter to read or edit data. An obsolete (no longer used) type of magnetic storage is a floppy disk but these have been replaced by solid state devices such as USB sticks which are much faster and have a much higher capacity. Another type of magnetic storage that is still used is magnetic tape . Magnetic tape has a high storage capacity but data has to be accessed in order (serial access ) so it is generally only used by companies to back up or archive large amounts of data . Magnetic Storage Characteristics: ​ ✓ - Large CAPACITY and cheaper COST per gigabyte than solid state . ​ X - Not DURABLE and not very PORTABLE when powered on because moving it can damage the device. ​ X - Slow ACCESS SPEED but faster than optical storage . ​ Optical Storage Optical storage uses a laser to project beams of light onto a spinning disc, allowing it to read data from a CD , DVD or Blu-Ray . ​ This makes optical storage the slowest of the four types of secondary storage. ​ Disc drives are traditionally internal but external disc drives can be bought for devices like laptops. ​ Magnetic Disks are spelled with a k and Optical Discs have a c. Optical Storage Characteristics: ​ X - Low CAPACITY : 700 MB (CD ), 4.7 GB (DVD ), 25 GB (Blu-ray ). X - Not DURABLE because discs are very fragile and can break or scratch easily. ✓ - Discs are thin and very PORTABLE . Also very cheap to buy in bulk. ​ X - Optical discs have the Slowest ACCESS SPEED . Solid State Storage There are no moving parts in solid state storage. SSD s (Solid State Drives ) are replacing magnetic HDDs (Hard DIsk Drives) in modern computers and video game consoles because they are generally quieter , faster and use less power . ​ A USB flash drive ( USB stick ) is another type of solid state storage that is used to transport files easily because of its small size. ​ Memory cards , like the SD card in a digital camera or a Micro SD card in a smartphone , are another example of solid state storage. Solid State Characteristics: ​ X - High CAPACITY but more expensive COST per gigabyte than magnetic . ​ ✓ - Usually DURABLE but cheap USB sticks can snap or break . ​ ✓ - The small size of USB sticks and memory cards mean they are very PORTABLE and can fit easily in a bag or pocket. ​ ✓ - Solid State storage has the fastest ACCESS SPEED because they contain no moving parts . Q uesto's Q uestions 2.2 - Secondary Storage: ​ 1. Rank magnetic , optical and solid-state storage in terms of capacity , durability , portability , speed and cost . For example, magnetic has the highest capacity , then solid-state, then optical. This could be completed in a table . [15 ] ​ 2. Justify which secondary storage should be used in each scenario and why it is the most appropriate: a. Sending videos and pictures to family in Australia through the post . [ 2 ] b. Storing a presentation to take into school . [ 2 ] c. Storing project files with other members of a group to work on together . [ 2 ] d. Backing up an old computer with thousands of files to a storage device. [ 2 ] 2.1 - Primary Storage Theory Topics 2.3 - Data Units

4.1: Boolean Logic Exam Board: OCR Specification: 2020 What is a logical operator? Inside of each computer system are millions of transistors . These are tiny switches that can either be turned on (represented in binary by the number 1 ) or turned off (represented by 0 ). ​ Logical operators are symbols used to represent circuits of transistors within a computer. The three most common operators are: ​ NOT AND OR What is a truth table? A truth table is a visual way of displaying all possible outcomes of a logical operator. The input and output values in a truth table must be a Boolean value - usually 0 or 1 but occasionally True or False. NOT AND OR A NOT logical operator will produce an output which is the opposite of the input . ​ NOT is also known as Negation . ​ The symbol for NOT is ¬ An AND logical operator will output 1 only if both inputs are also 1 . ​ AND is also known as Conjunction . ​ The symbol for AND is ∧ An OR logical operator will output 1 if either input is 1 . ​ OR is also known as Disjunction . ​ The symbol for OR is ∨ NOT Logic Gate AND Logic Gate Symbol OR Logic Gate Symbol Truth Table Truth Table Truth Table Multiple Operators Exam questions could ask you complete truth tables that use more than one logical operator . Work out each column in turn from left to right and look carefully at which preceding column you need to use. NOT B A AND NOT B A OR (A AND NOT B) Logic Diagrams You may be asked in an exam to d raw a logic diagram when given a logical expression . ​ Draw any NOT symbols or expressions in brackets first. A logic diagram for C = ¬A ∧ B A logic diagram for D = C ∨ (A ∧ B) Q uesto's Q uestions 4.1 - Boolean Logic: ​ 1. Copy and complete the following truth tables: ​ ​ ​ 1b. Simplify the expression in the second truth table. ​ 2a. A cinema uses a computer system to monitor how many seats have been allocated for upcoming movies. If both the premium seats and the standard seats are sold out then the system will display a message. State the type of logical operator in this example. 2b. For the more popular movies, the cinema's computer system will also display a message if either the premium seats or the standard seats have exclusively been sold out. However, it will not output a message when both have been sold out. State the type of logical operator in this example. ​ 3. Draw a logic diagram for C = (¬B v A) ∧ A . 3.2 - Testing Theory Topics 5.1 - Languages & Translators

Eduqas / WJEC GCSE Computer Science These pages are based on the Eduqas GCSE Computer Science 2020 specification . The content can also be used by students studying WJEC GCSE Computer Science in Wales . This website is in no way affiliated with Eduqas / WJEC . 1. Hardware 1.1 - The Central Processing Unit (CPU) 1.2 - The FDE Cycle 1.3 - Primary Storage 1.4 - Secondary Storage 1.5 - Performance 1.6 - Additional Hardware 2. Logical Operators & Boolean 2.1 - Logical Operators 2.2 - Boolean Algebra 3. Networks & Security 3.1 - Network Characteristics 3.2 - Data Packets & Switching 3.3 - Network Topology 3.4 - Network Hardware & Routing 3.5 - Protocols 3.6 - 7-Layer OSI Model 3.7 - The Internet 3.8 - Cyber Threats 3.9 - Protection Against Threats 4. Data 4.1 - Number Systems 4.2 - Signed Binary 4.3 - Binary Calculations 4.4 - Arithmetic Shift 4.5 - Character Sets & Data Types 4.6 - Graphical Representation 4.7 - Sound Representation 4.8 - Compression 5. Data Organisation 5.1 - Data Structures & File Design 6. Operating Systems 6.1 - Operating Systems 6.2 - Utility Software 7. Principles of Programming 7.1 - Language Levels 8. Algorithms & Constructs 8.1 - Programming Principles 8.2 - Understanding Algorithms 8.3 - Writing Algorithms 8.4 - Sorting & Searching Algorithms 8.5 - Validation & Verification 9. Software Development 9.1 - IDE Tools 10. Program Construction 10.1 - Translators 10.2 - Stages of Compilation 10.3 - Programming Errors 11. Technological Issues 11.1 - Impacts of Technology 11.2 - Legislation Component 2 (Programming Exam) Python Removed content from the 2016 Specification

Exam Board: OCR 3.2b - Structured Query Language 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 3.2b - Structured Query Language: ​ 1. What is cache memory ? [ 2 ] ​ 3.2a - Databases & Normalisation Theory Topics 3.3a - Network Characteristics

3.5 - Business Systems Exam Board: OCR Specification: 2016 - Unit 1 Businesses have developed many systems to manage and manipulate data and aid business practices. Management Information System (MIS) An MIS is used to collect, store, analyse and present data for an organisation. The system processes a large amount of data and organises it (such as in databases) so that it can be used for decision making and general data analysis . An efficient MIS can be used to display the financial status of an organisation, highlight areas of improvement and generate sales forecasts based on current data. Specifically, a bank could use an MIS for: Looking at numbers of customers that visit each branch. Forecasting takings based on historical data. Profiling customers. Identifying customers who haven’t saved recently to target them for email. Benefits of an MIS: ​ Integrated system: ​ A Management Information System shares a large amount of data from multiple departments within an organisation to produce accurate reports. For example, financial data can be used to generate accurate pay slips. Decision Making: An MIS can be used to inform an organisation's decision making by highlighting areas that need improvement within the company. Powerful analysis: ​An MIS will use large data sets to provide accurate data analysis that can be used in many different ways by an organisation. Trends and patterns can be identified easily. Backup capabilities: ​ Data can be stored centrally and backed up easily if a disaster occurs. Limitations of an MIS: ​ Cost and installation: ​ An MIS is an expensive tool that needs to be professionally set up and requires technical knowledge to maintain. Requires accurate data: ​ If any data is incorrect or out of date then the analysis will consequently be inaccurate . Potentially disastrous decisions could be made as a result of incorrect data. Training: Employees will need to be trained to use the software accurately for maximum efficiency. Customer Relationship Management (CRM) A CRM system is used to improve the relationship between an organisation and its customers . It can be used to increase customer loyalty with those who already subscribe to their services as well as used to try and increase the customer base by attracting new customers. The ultimate goal of a CRM system is to increase and retain customers which will result in more sales and higher profits . Examples of CRM systems: Marketing teams tracking which promotions customers are responding well to . Customer service teams responding quickly to customer complaints , through a variety of channels (such as social media, emails and telephone calls). Marketing teams rewarding customers who have spent a certain amount in a year. Standard Operating Procedures (SOP) A standard operating procedure is a comprehensive step-by-step guide of how to carry out a business routine. An organisation will create an SOP to abide by legal requirements and high company standards . SOPs must be followed in exactly the same method each time and by each employee to ensure the same outcome and remove any inconsistencies . ​ Benefits of Standard Operating Procedures: ​ Ensures consistency: ​ The outcome should be the same each time when following SOPs which ensures an efficient result . Fewer errors: ​ If all employees follow the SOP carefully then there should be no errors . Meets legal requirements : The SOPs will be designed to meet up-to-date legislation as well as any standards that the company have set. Limitations of Standard Operating Procedures: ​ Inflexible practice: ​ A lot of time may be spent on creating the paperwork and admin instead of the actual job. Legal updates: ​ The SOPs must be periodically reviewed and updated to take into account any new laws . Sales Ordering Process (SOP) This is the process of a customer buying a product or service and the company reviewing the purchase. 1. The customer orders a product or service, usually via email or telephone conversation. 2. The order is confirmed and a sales order is created. This is a document that lists the customer’s requirements and exactly what they have purchased. 3. The sales order is sent to the relevant departments (e.g. production, finance and delivery) so they can fulfil the customer’s request . Once the order has been completed the customer will be sent an invoice for payment . The SOP is important as it creates a clear plan for ordering a product. Each department can use the sales order to know exactly what jobs to perform. Help Desk Help desk software is used to provide real-time support to a user from a trained member of staff to overcome a technical problem . The customer logs an issue in the form of a ticket and is assigned a technician . As the technician tries to communicate with the user and solve the issue they must follow a service level agreement that defines the high standards the technician must keep to. When the problem has been solved the ticket is closed. All tickets are archived so that persistent problems can be checked. If Help Desk software is used within a company to report and solve issues it is known as in-house . Benefits of Help Desk software: ​ Keeping Track: ​C ustomers can see that their issues are being dealt with and administrators have clear records of the problem. Audit Logs: All tickets are archived so if a problem occurs on the same machine the previous solution can be attempted again . Communication : Formal messages between the customer and the administrator mean there are no mixed messages and a running dialogue can take place as the problem is fixed. Limitations of Help Desk software: ​ Cost : Setting up the necessary software and hardware and paying for an administrator to run the system can cost a large amount of money. Availability issues: ​ A technician might not be available 24/7 or during holidays. Formal structure: ​ This is a formal system that takes time to record and respond to which might annoy staff when it is only a minor issue to be fixed, like resetting a password. Knowledge: ​ Technicians need technical expertise regarding the company's computer systems and need to be able to fix both hardware and software issues. This might require additional training every few years. Ticket Response Time: ​ Administrators must ensure that all tickets are read and responded to in reasonable time so that productivity in the company is not affected. Q uesto's Q uestions 3.5 - Business Systems: 1a. What is the purpose of an MIS ? [ 2 ] 1b. Describe 3 ways a bank could use an MIS . [ 3 ] 1c. Describe the benefits and limitations of an MIS . [10 ] ​ 2a. What is the purpose of a CRM ? [ 4 ] 2b. Describe 3 ways that a CRM could be used by a company . [6 ] ​ 3a. What are standard operating procedures (SOP ) and why are they used? [ 4 ] 3b. Describe the benefits and limitations of SOPs . [ 10 ] ​ 4a. What is the sales ordering process ( SOP )? [ 2 ] 4b. Why is the SOP important in a company? [ 2 ] 4c. Summarise the 3 stages of the SOP . [ 4 ] ​ 5a. What is the purpose of help desk software? [ 2 ] 5b. Explain how help desk works , including tickets , technicians and service level agreements . [3 ] 5c. Describe the benefits and limitations of Help Desks . [ 10 ] 3.4 - Connection Methods Topic List 4.1 - Communication Methods

This walkthrough will show you how to create a maze game in Scratch . It is split into the following sections: ​ Creating the First Level Choosing the Main Character Animating & Moving the Main Character Back to the Start Adding Score & Time Making Enemies Adding More Levels Extensions Use the links to move between sections easily! 1. Creating the First Level The very first thing to do is to create the level in which our character will move around in! We are going to draw a background from scratch which our hero will run around in to get to the end. ​ Important parts of the pictures are highlighted in yellow ! 1. Select the blank Stage button in the button left to edit the background. Drawing the Background Challenge Task Anchor 1 2. Press on the Backdrops tab. This will show Scratch’s own paint editor on the right. 3. Use the line tool to create straight maze lines on the background. Use the slider at the bottom to increase the width of the line. Remember this is only the first level so don’t make it too difficult. 4. Create a start zone and an end zone with the rectangle tool and then fill them in with the fill bucket tool . You can also change the main background colour using the fill bucket tool. Remember to choose an appropriate level name in the text box at the top. Level Name Rectangle Tool Fill Bucket Tool Make your game more exciting by creating themed levels , like this park background. Other ideas might include a classroom, library or car park. Try switching up the start and end zones by using the circle tool or the line tool and the fill bucket . Come back to this challenge when you are ready to make more levels! 2. Choosing the Main Character Now that you have your first level designed we can make our hero character who is going to navigate the maze and try to get to the end. Picking the main character Anchor 2 1. A character is called a sprite . We will choose a sprite from Scratch’s sprite library . Click on the fairy icon to open the sprite menu. 2. I have selected the Animals category on the left menu. ​ I have chosen the Penguin sprite but choose whichever character you want. 3. Press the Costumes tab and check that your chosen sprite has at least two costumes . We will use these to create animation in the next section to make it look like the sprite is moving. 4. Now that we don’t need the cat anymore we can delete him by right-clicking on his icon and selecting delete . Shrink the Main Character down to size Shrink Tool 5. The sprite is too big for the level background and you will need to shrink them down . Click on the shrink button at the top of the program and then click on the sprite in the paint area to shrink them down. Remember how many times you clicked the sprite to shrink it. You will need to shrink both costumes the same number of times . Here I have shrunk my penguin by 17 clicks when I selected the shrink tool. You can compare the size of your costumes by looking at the image size beneath the icon (e.g. 40 x 53). Picture Size 6. You need to make sure that your sprite is in the centre of the grid otherwise it might cause trouble later when you try to move them. Click on the costume centre button in the top right (it looks like a crosshair ) and drag your sprite into the middle if it is not. Make sure that both costumes are in the centre . Also, give your costumes appropriate names , I have named mine Mr. Penguin 1 and Mr. Penguin 2. Costume Name Costume Centre 3. Animate & Move the Main Character Adding Animation Anchor 3 1. Click on your sprite icon in the bottom left and then on the Scripts tab in the top centre. We will begin using the script blocks and we need to start in the Events category with: ​ ...so drag it over to the script area. ​ This script will run all the blocks that we place beneath it, when the flag is pressed to start the game. 1. 2. You can only add animation if the sprite you chose has at least two different costumes! 2. The second block we need is: ​ ​ ...in the Control category. Every block that we put inside the forever loop block will repeat again and again . We want our character to switch between their costumes infinitely to make it look like they are always walking, which is why we use the forever loop. 3. Click on the Looks category and drag two... ​ ...inside of your forever loop . Use the drop down list (small black triangle on the costume block ) to make one block switch to your first costume and the other block switch to your second costume. 4. In the Control category, drag over two ​ ​ ​ blocks and place one after each of your ‘switch costume to ‘ blocks. 1 second is too long to wait so click on the 1 and change both to 0.5 instead (this is half a second). If you’ve got the code correct so far, when you press the green flag your character should be animated! Moving the Main Character 1. In the Events category drag a ​ into the script area. Change the button from space to ‘up arrow ’ (or any key you like) It is also popular for computer games to use the w key to move up. 2. Click on the Motion category and move over two blocks: ​ and ​ ​ Change the angle of direction from 90 (which is a right turn) to 0 (which is an upwards turn). Now you have just created code to make your character move upwards by ten steps when you press the up arrow! Once you have dragged the blocks when the up arrow is pressed, you can work out how to make your character move down, left and right ALL BY YOURSELF. ​ Add this code in now, before you move on . Rotate the Main Character If you press the green arrow and move your character around you might notice that it doesn't rotate when it moves. Click on the i in the top left of your sprite icon in the bottom left. There are three types of rotation to choose from. Select your preferred style by clicking on one of the three symbols. Full Rotation will turn your sprite up, down, left and right. Horizontal Rotation will only turn your sprite left and right. No Rotation will not turn your sprite at all. it will always appear in the same direction. Anchor 4 4. Back to the Start Starting in the right place We always want the main sprite to start in the green zone when the green flag is pressed to start the game. ​ First drag your sprite to the green zone . Then go to the Motion category and drag over: ...and connect it directly underneath the ​ ​ ​ block you dragged over earlier. Once you’ve added that line of code, click the green flag to make sure that the sprite starts where you want it to . If it doesn’t, then you can change the x (horizontal) and y (vertical) co-ordinates by clicking on the white boxes and changing the values. Back to the start if touching the walls 1. Drag over and connect together the two blocks below: 2. Drag over the two blocks below, put the blue one inside the other and then put them both inside the forever loop : 3. Change the co-ordinates in the blue block you just added so that it matches the same co-ordinates as the block to make the sprite start at the green zone . 4. Now to add the wall detection code! In the Sensing section, drag this block over... ...and put it inside the top of the ‘if then‘ block . ​ Make sure that you put it between the 'if' and 'then' and not underneath. 5. Click once on the box in the ‘touching colour ‘ block and then click the wall or obstacle you want the player to avoid, Now is a good idea to play your game and make sure you can get to the end without being teleported back to the start. If your game is impossible you will need to edit the background – click on the stage icon in the bottom left then the Backdrops tab and edit the walls. Anchor 5 5. Adding Time & Score Recording the Time 1. Click on the Stage icon in the bottom left, we will create new code in the Scripts tab of the stage. DO NOT click the character sprite! Click on the Data category and choose Make a Variable . ​ A variable is something that can change . Call your new variable Time . Adding a Score - The Number of Restarts 2. From the Events category drag: ​ ​ ​ ...then look in the Data category and connect this underneath: ​ ​ ​ ...but it should say Time instead of 'variable'. ​ This code makes the time start at 0 when the game begins. 3. Now we need a loop that increases our variable called Time by 1 every second. First drag over a forever loop : ​ ​ ​ Then place inside of it two blocks: ​ ​ ​ ​ Make sure it says Time instead of variable. ​ Now press the green flag to see the timer go up. 1. In the Data section click on Make a Variable and give it an appropriate name like Restarts . This variable will count how many times we have touched a wall and had to start again. 2. Firstly, go back to the Scripts area for your character – click on the sprite of your main character in the bottom left then the Scripts tab. You need to add two blocks from the Data category: ​ ​ ​ Change variable to Restarts and place it directly underneath the flag. ​ ​ ​ Change variable to Restarts again and place this code directly after the 'go to ' block inside the loop. ​ Now whenever you touch the wall you restart and it records it in the variable called Restarts. 6. Making Enemies Anchor 6 1. Select the fairy icon in the New sprite section to open the Scratch sprite library. 2. From the sprite library choose your enemy . I have selected the polar bear because it fits with my penguin. 3. Select the shrink tool at the top of the program and click on the enemy . Then drag them to where you want them to start . 4. Click on the sprite icon of your enemy then select the Scripts tab. Drag and connect two blocks: 5. From the Control category grab a: ...and place it after the ‘go to ‘ block. Now we will make our enemy glide from his start position to somewhere on our level again and again. Move the enemy to where you want it to go to then add: ...inside the forever loop. Drag another ‘glide ‘ block and place it underneath but change those co-ordinates to the same as the one underneath the the ‘when green flag clicked‘ block. ​ This code makes the enemy move backwards and forwards forever. 6. Make your main character return to the start if they touch the enemy. ​ Click on your main character sprite in the bottom left and then the Scripts tab. ​ You need to copy the exact same code you made earlier to see if the main character is touching the wall , but this time you need to use: ​ ​ ​ ...instead of the touching colour block. ​ Click on the box in the block and select your Main Character . ​ 7. New Levels Anchor 7 Coming Soon To be added soon. This concludes the walkthrough for a Scratch maze game! Try a combination of the suggestions below to add complexity to your game: ​ Using ‘say ‘ or ‘think ‘ blocks in the Looks category to make your sprites say things at certain points (like at the start of a new level). Making your game harder by speeding up enemies in later levels (you could change the number of seconds it takes to glide ) Adding more enemies that only appear in harder levels. Setting a time limit – instead of having your time begin at 0 and increasing by 1 every second, have it start at 30 and decrease by 1 every second. Extensions Anchor 8

Exam Board: OCR 3.1b - Encryption & Hashing 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 3.1b - Encryption & Hashing: ​ 1. What is cache memory ? [ 2 ] ​ 3.1a - Compression Theory Topics 3.2a - Databases & Normalisation

Exam Board: OCR 1.3a: Input & Output Devices 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 1.3a - Input & Output Devices: ​ 1. What is cache memory ? [ 2 ] ​ 1.2 Processors Theory Topics 1.3b - Memory & Storage

Memory What is memory? Memory, also known as primary storage, is used by a computer to store data and instructions . ​ Memory is quick because the CPU can access it directly . ​ Memory is important because it allows the computer to multi-task . Types of Memory RAM ( R andom A ccess M emory) RAM is volatile (this means that when power is lost, the data is deleted ). Every program that is being run by the computer (such as Google Chrome, Spotify or Microsoft Word) is stored in RAM . RAM is made up of a large number of storage locations , each can be identified by a unique address . ROM ( R ead O nly M emory) ROM is non-volatile (this means that data is saved, even when the power is off ). The start-up instructions (for when a computer is turned on) are stored in ROM . ROM is read-only, which means that it cannot be edited or changed . Cache Memory Cache memory is fast to access because it is very close to the CPU . Cache memory stores data that needs to be accessed very frequently . Cache memory is very expensive , so there is only a small amount in most computers. How can you make a computer faster? If you are trying to run too many programs at the same time , ​there might not be enough space in RAM . ​ Try closing applications and processes that you do not need. Persistently slow computers could be helped by increasing the amount of RAM on the motherboard. KS3 Home