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Learn about software errors and troubleshooting methods of solving them. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 2.6 - Software Troubleshooting Exam Board: OCR Specification: 2016 - Unit 1 A software error occurs when a program or process stops working as expected. Software errors usually occur when programs are badly written or if a user inputs unexpected data . Common Faults System Freeze The computer freezes and pressing keys or moving the mouse gives no response . Commonly caused by having too many applications running simultaneously or a virus using too much memory . Unexpected Reboot To try and fix errors, a computer might get stuck in an endless loop of booting and rebooting . Other systems may frequently restart without warning . Stop Error This occurs after a fatal system error when the operating system stops , usually because of a driver software issue . Commonly known as the 'blue screen of death ' on Windows-based systems. Update Error While designed to fix errors, updates can sometimes bring more problems if they interfere with the current software . Troubleshooting Tools for Software Errors Event Viewer (Logs) If a software error does occur, then the same characteristics as a hardware error should be logged , such as the time and date of the error , the user logged in , and the device's problem history . Memory Dump Copies and displays the contents of RAM at the time of a crash to help a technician discover what happened . Baselines Before After A comparison of what the system is like after a crash compared to a fixed point in time beforehand. The baseline can be used to see differences which may have caused the computer to fail . Anti-Virus Checks if malware is running on a device, using up resources and slowing the system down. It could then be quarantined and deleted by the anti-virus. Installable tools can also be downloaded to investigate the system and find the cause of the problem . They may help detect corrupted files , uncover deleted files , and resolve other general hardware or software issues . Q uesto's Q uestions 2.6 - Software Troubleshooting: 1. Describe each of the four common types of software error : a. System Freeze b. Stop Error c. Unexpected Reboot d. Update Error [2 each ] 2. Describe each type of troubleshooting tool and explain how it can be used to discover and fix software errors. a. Event Viewer b. Memory Dump c. Baselines d. Antivirus Software e. Installable Tools [ 2 each ] 2.5 Communication Methods Topic List 2.7 - Protocols

Learn about how information can be classified into groups including private, public, sensitive and confidential. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 2.2 - Information Classification Exam Board: OCR Specification: 2016 - Unit 2 Information can be classified into different groups . Some data may fall into more than one classification. Sensitive Information Description: Information that should be protected from being publicly released as it could harm the safety or privacy of an organisation or an individual . Examples: Medical data that could be embarrassing to an individual if released. Financial data that will negatively impact the company if made public to competitors. Non-Sensitive Information Description: Information that can be released publicly with no fear of negative consequence . Examples: Store information including shop addresses , opening hours and the names of senior managers. Product information including prices , online reviews and general availability . Private Information Description: Private information relates to an individual and it should not be shared with anyone else without the data subject's permission . Private information is protected by the Data Protection Act and would need to be stored securely so it cannot be accessed without authorisation. Examples: Home addresses, contact information, birth dates and banking details . Employee data such as linked bank accounts and addresses. Public Information Description: Released to the public and can therefore be seen by anyone . Public information is non-sensitive . Examples: Social media usernames, posts and shared images. Public business information including addresses, promotional material and opening times. A government report like the national census every ten years. Personal Information Description: Identifiable data about a specific individual . Examples: Full name , date of birth , gender , marital status, medical history, sexual orientation and voting history. Business Information Description: Any kind of data about a specific business. This information could be public or private. Examples: Address of its headquarters Financial data or employee details. Annual sales figures . Confidential Information Description: Private data that is more restricted than sensitive information , with access limited to only those who need to know. Examples: Doctor / therapist notes Business Profits and losses Trade secrets Classified Information Description: Highly sensitive information stored by a government institution , requiring the highest levels of restricted access . Access is usually restricted by law and only viewable by authorised individuals or groups. In the UK there are three levels of classified information: OFFICIAL , SECRET and TOP SECRET . Examples: Military data Terrorism precautions Crime scene reports Anonymised Information Description: Anonymisation removes personally identifiable data from information so that an individual cannot be identified . This allows the information to be used in much wider context without running the risk of legal action. Examples: Partially anonymised information - where some of the personal information has been removed and replaced by a symbol . Completely anonymised information - where all identifiable data has been removed . Bank details are often partially or completely anonymised. A partially anonymised credit card number might be listed as: **** - **** - **** - 7427 Problems with anonymising data include: If sensitive data is not anonymised enough and the person can be identified . Useful information could be lost if too much data is anonymised . The public could lose trust in an organisation if data is insufficiently anonymised . Q uesto's Q uestions 2.2 - Information Classification: 1. Describe each type of information classification and give at least two examples : a. Sensitive information [3 ] b. Non-Sensitive information [3 ] c. Private information [3 ] d. Public information [3 ] e. Business information [3 ] f. Confidential information [3 ] g. Classified information [3 ] h. Anonymised information (partial and complete) [6 ] 2. State which classification(s) the following pieces of information would be categorised as. It might fit into more than one category. a. Shop opening times [1 ] b. Medical history [1 ] c. Twitter username [1 ] d. Crime scene report [1 ] 3. Describe three problems that organisations should consider when anonymising data . [6 ] 2.1 - Information Styles 2.3 - Quality of Information Topic List

Learn about the different methods of communication using physical and digital ways of transferring data. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 2.5 & 4.2: Communication Methods Exam Board: OCR Specification: 2016 - Unit 1 Sections 2.5 and 4.2 are very similar so both are mixed within this page. There are many ways that employees of a business can communicate between staff members or with their customers . Text-based Communication Letter ✓ It is a traditional method of communication that can be used for formal occasions such as job offers or resignations . ✓ It can be kept and stored for physical evidence - e.g. keeping an applicant's CV in case an opportunity arises in the future. X Requires postage costs to be sent in the mail (a first-class stamp is now £1.65 ). Overseas delivery is even more expensive . X Takes several days time to be received in the post and may be lost . X A letter can't include certain formats like video. Text Message (SMS) ✓ Can reach a large audience at once with one batch message . ✓ Good for short messages - e.g. appointment reminders or confirmation codes for two-factor authentication . ✓ Doesn't require an internet connection to receive messages. X Limited to short messages (160 characters ) with no multimedia . X Text messages can cost to send each message. SMS stands for Short Message Service . Email ✓ Easily send information to many people at once, instantly . ✓ Can include documents , multimedia attachments and links . ✓ Can send targeted emails to customers on a mailing list with new products or sales promotions . X Important messages may be lost in the spam folder. X Phishing scams can spread malware via email attachments. Instant Messaging ✓ Works in real-time - messages are sent and received instantly . ✓ Attachments and hyperlinks can be sent. ✓ Can be used by support staff to help customers in real-time. X Quick speed means it's less suitable for formal conversations like interviews. X Internet access issues will disrupt any conversations . Voice-based Communication Cellular ✓ Can hear how something is said , unlike text responses. ✓ Fastest method of communication - also allows reactive conversations that can quickly change based on previous responses. X Impacted by cellular reception - won't work in remote areas / underground. X Can't see the other person's body language, presentation or facial expressions. Teleconferences ✓ Allows for groups of people to communicate at once . ✓ Businesses can use teleconferencing to communicate between offices / individuals across the world . X The quality of the call may be affected by a group's poor reception . X Because a group is communicating, people may speak over each other , especially if there is a time delay . VoIP (Voice over Internet Protocol) ✓ Allows a user to make calls over the internet (e.g. using WhatsApp). ✓ Cheaper (can also be free) to make calls rather than using a cellular network . X Relies on a good-quality internet connection . X Can potentially be less secure than cellular connections. hi there Personal Assistants ✓ Speeds up processes by making appointments, checking information or connecting to smart devices. ✓ Voice-activated - can be used whilst otherwise busy , such as typing, cooking or driving. ✓ The language can be changed to suit people's preferences. X Huge privacy concerns as companies store audio data for voice recognition and track all commands made to the device. X There may be recognition issues as sometimes the assistant doesn't understand a command . Online Communication Video Conferences ✓ Users can connect to the call (e.g. using Zoom, Skype, or Google Meet) remotely , saving time and money instead of all travelling to one location. ✓ Can be used for interviews as it allows the applicant and the interviewers to see each other and look for body language . ✓ Users can share information visually , such as designs. X A high-bandwidth connection is required to send and receive video data reliably . X A poor internet connection (e.g. a weak WiFi signal ) will result in low-quality video that may stutter or drop out , making it hard to communicate clearly . Social Media ✓ Businesses can quickly share information with a large online audience , including new potential customers . ✓ Posts can be in d i fferent formats such as text, images, videos or links to other websites. ✓ Direct messages sent on social media may be seen and responded to faster than alternatives like using email if push notifications are enabled on a phone. ✓ Some social media sites like Facebook allow for private , invite-only groups to communicate with like-minded users in a secure way. X Businesses must be cautious about what they post so as not to accidentally offend others and damage their reputation . X Social media posts and customer comments must be carefully managed , so a social media manager should be hired. Blog / Vlog ✓ Share information with followers in text , images and video formats . ✓ Blogs and vlogs can unite people with similar interests , such as a cookery blog or travel vlog. ✓ Companies can use a blog to promote new products and provide details of upcoming events to try and attract new customers . X Takes a lot of effort and time to create posts, especially editing videos for vlogs. X Bad behaviour or language in vlogs can bring punishment. Several YouTubers have lost their reputations following videos they have posted. Q uesto's Q uestions 2.5 & 4.2 - Communication Methods: 1. Describe three advantages and three disadvantages for each type of communication method . You will need to think of or research some more than the examples listed on this page. a. Letter b. SMS (Text Message) c. Email d. Instant Message e. Cellular Call f. Teleconference g. VoIP Call h. Personal Assistant i. Video Conference j. Social Media k. Blog / Vlog [6 each ] 2. Explain what VoIP stands for and what it allows a user to do. [ 2 ] 3. Describe which communication method would be most appropriate for the following scenarios and why : a. Informing your boss you are going to resign. b. Communicating with management about raising your pay. c. Chatting to team members about when the Christmas party is. d. Sending promotions to thousands of customers. e. Interviewing a potential new employee who is in a different country. f. Talking with a group of investors about the company's latest data. [2 each ] 2.6 - Software Troubleshooting 2.4 Operating Systems 4.1 Communication Skills 4.3 - Personal Attributes Topic List

Learn about computational methods including problem recognition, decomposition, divide and conquer, abstraction, backtracking, data mining, heuristics, performance modelling, pipelining and visualisation. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level Specification: Computer Science H446 2.2 - Computational Methods Watch on YouTube : Problem recognition Decomposition Divide and conquer Abstraction Backtracking Data mining Heuristics Performance modelling Pipelining Visualisation Computational methods are techniques to analyse problems and design efficient , effective solutions . Problem Recognition Problem recognition is the process of identifying that a problem exists and understanding its nature before attempting to solve it. It involves determining the aims of the task , identifying constraints and requirements , and clarifying what inputs , outputs and processes are expected from the solution . Effective problem recognition ensures the developer understands the real-world context and avoids solving the wrong problem or missing key details . It is the essential first step that guides all later stages of computational thinking and system design . YouTube video uploading soon Decomposition Decomposition involves breaking a complex system or task into smaller , more manageable components that are easier to design , implement and test . Each sub-problem should ideally be independent and solve a specific part of the overall task , which helps reduce complexity and supports modular program design . This approach enables different developers to work on different components simultaneously and simplifies debugging , maintenance and future updates . By working through smaller logical parts , the full problem becomes far more approachable and structured . YouTube video uploading soon Divide and Conquer Divide and conquer is a technique that splits a problem into smaller sub-problems of the same type , solves them (often using recursion ), and then combines the solutions to produce the final answer . This approach can significantly improve efficiency by reducing large input sizes into more manageable chunks , as seen in algorithms like quicksort . Divide and conquer algorithms include a binary search and a merge sort . The time complexity of divide and conquer algorithms is logarithmic - O(log n) - allowing complex problems to be solved much quicker than other algorithms . YouTube video uploading soon Abstraction Abstraction means removing unnecessary details to focus only on the most important features of a problem or system . It allows programmers to create simplified models that capture essential behaviour without becoming overwhelmed by irrelevant complexities . Abstraction enables generalisation , reusable designs and clearer reasoning about how components interact . In computational contexts, abstraction also highlights the difference between real-world systems and their simplified computational models . YouTube video uploading soon Backtracking Backtracking is used to explore possible solutions to a problem by building a partial solution and abandoning it as soon as it becomes clear it cannot succeed . It works by trying an option , checking whether it leads towards a valid solution , and backtracking to try a different path if a dead end is reached . This approach is used in constraint-based problems such as maze solving . While powerful , backtracking can be computationally expensive , so it often benefits from heuristics or pruning strategies . YouTube video uploading soon Data Mining Data mining is the process of extracting useful patterns , trends and relationships from large datasets . It enables organisations to identify hidden insights , predict behaviours and support data-driven decision-making , particularly in fields such as marketing , healthcare , finance and security . Data mining can lead to enhanced decision-making that can result in innovation , a competitive advantage against similar organisations and increased revenue . It can be used to identify anomalies or unused features . However, data mining doesn't explain the patterns it can identify and it requires powerful computers with a lot of processing power to handle huge amounts of data . YouTube video uploading soon Heuristics Heuristics are approximate problem-solving strategies that aim to produce good solutions quickly when exact , optimal methods are too slow or computationally impractical . They rely on rules of thumb to guide searches through very large solution spaces efficiently . Heuristics are widely used in artificial intelligence , optimisation tasks and complex search algorithms such as A* , where perfect accuracy is less important than fast , practical solutions . The trade-off is that heuristic methods are not guaranteed to produce the optimal answer , but they dramatically reduce processing time . YouTube video uploading soon Performance Modelling Performance modelling is the process of predicting how a system or algorithm will behave under different workloads , input sizes or hardware environments . It uses tools such as mathematical analysis , simulation and Big O notation to estimate required resources such as processing time or memory use . Performance modelling offers a cheaper , quicker and often safer way to test applications . For example, when a company beta tests an online game , it can trial the system with a smaller group of players and then apply performance modelling to predict how much server capacity will be needed when the game is fully released . YouTube video uploading soon Pipelining Pipelining is a technique in which different stages of a process are overlapped so that multiple instructions or operations are being processed simultaneously at different stages . In CPU architecture , for example, one instruction might be fetched while another is decoded and a third is executed , increasing overall throughput without increasing clock speed . Pipelining can also be used in algorithms or data-processing systems to prevent idle time in stages that operate independently . However, pipelining introduces complexity because dependencies or branch mispredictions may require a pipeline to be flushed - interrupting flow and reducing efficiency . YouTube video uploading soon Visualisation Visualisation supports the understanding of a problem by presenting information in a clearer and more accessible form than text alone . It is useful for explaining complex ideas or identifying patterns . Data can be shown visually through diagrams , graphs , trees , flowcharts or tables . The advantages of visualisation include helping to model , represent , analyse or summarise complex concepts . It allows information to be communicated more clearly and in a way that is easier to interpret . It can also provide different perspectives on how a problem might be solved . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Computational Methods: problem recognition, decomposition, divide and conquer, abstraction, backtracking, data mining, heuristics, performance modelling, pipelining, visualisation D id Y ou K now? Real-time location services like Google Maps use heuristics to guess travel times using heuristics such as estimated speeds , traffic history and shortcuts to make fast but approximate route suggestions . 2.1 - Programming Techniques A-Level Topics 3.1a-d - Algorithm Complexity

Learn about programming constructs such as sequence, iteration and branching, recursion, local and global variables, modularity, functions and procedures, parameter passing by value and by reference, Integrated Development Environment (IDE) tools and object-oriented techniques. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level Specification: Computer Science H446 2.1 - Programming Techniques Watch on YouTube : Programming constructs Recursion Local & global variables Modularity Integrated development environment Object-oriented programming Programming Constructs Sequence , iteration and branching (also called selection ) are the three fundamental programming constructs used to build algorithms . Sequence means that instructions run in a specific order , one after another. Iteration is the repetition of a set of instructions , usually being count-controlled , such as for loops , or condition-controlled , such as while loops or do until loops . Branching (selection ) allows a program to choose between different actions based on a condition , using structures like if , elif , else or switch . YouTube video uploading soon Recursion Recursion is where a function calls itself to solve a problem by breaking it down into smaller , simpler versions of the same problem . Recursion is often used for tasks that naturally fit a 'divide and conquer ' structure , such as quicksort and merge sort algorithms. It is also used for depth-first tree traversals and solving mathematical problems like factorials or the Fibonacci sequence . Compared to iteration , recursion can produce clearer and more elegant solutions , but it may use more memory and can be less efficient if the recursion goes too deep or lacks a proper base case (stopping condition ) , potentially running out of memory . YouTube video uploading soon Local & Global Variables Local variables are created inside a function or block and can only be accessed there , which makes programs safer and easier to debug because changes to the variable cannot affect other parts of the program ; however, they cannot store values that need to be shared across multiple functions . Global variables are declared outside all functions and can be accessed anywhere in the program , making them useful for storing information that many parts of the program need , but they can lead to errors if different functions accidentally change them and can make the program harder to maintain . YouTube video uploading soon Modularity Modularity is the practice of breaking a program into smaller , self-contained parts so each section can be developed , tested and understood independently . Functions and procedures are modular units of code: a function returns a value , while a procedure performs a task without returning a value . When data is passed into a subroutine , it can be passed by value , where a copy of the data is sent so the original cannot be changed , or passed by reference , where the subroutine receives direct access to the original data , allowing it to be modified . YouTube video uploading soon Integrated Development Environment An Integrated Development Environment (IDE ) is software that provides the tools a programmer needs to write , test and debug code in one place . It typically includes an editor for writing and formatting code , syntax highlighting to make keywords and errors easier to spot , and auto-completion to speed up coding . For debugging , an IDE often provides error diagnostics that highlight mistakes , a run-time environment to execute the program , and tools like breakpoints and step-through execution that allow the programmer to pause the program and inspect variables to find and fix bugs more easily . YouTube video uploading soon Object-Oriented Programming Object-oriented techniques are a way of designing programs by modelling them as collections of objects , each representing something with its own data and behaviours . These objects are created from classes , which act like blueprints describing the attributes (data ) and methods (actions ) an object will have . It uses key principles such as encapsulation (keeping an object’s data and methods together and protected ), inheritance (allowing classes to share and reuse features ) and polymorphism (enabling objects to behave differently ). These techniques make large programs easier to organise , maintain and extend by encouraging reusable , modular and well-structured code . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Programming Constructs: sequence, iteration, selection (branching), if / elif / else, select (switch) case Recursion & Iteration: count-controlled loop, condition-controlled loop, recursion, base case Variables: local variable, global variable Modularity: function, procedure, parameter, pass by value, pass by reference Integrated Development Environment (IDE) Object Oriented Programming (OOP): class, object, method, attribute, inheritance, encapsulation, polymorphism D id Y ou K now? Roblox Studio is a free IDE for making Roblox games using the programming language Lua . With over 70m daily Roblox players , games built in Roblox Studio can reach a larger audience than many mainstream game engines . 1.1 - Computational Thinking A-Level Topics 2.2 - Computational Methods

Learn about the six main validation checks - range, type, length, format, lookup table and presence. Also, discover three verification checks - double entry, proof-reading and check digits. Based on the 2020 Eduqas (WJEC) GCSE specification. 8.5: Validation & Verification Exam Board: Eduqas / WJEC Specification: 2020 + What are validation and verification checks? Validation is a process to check that data is reasonable or sensible before it is accepted . Verification is the process of checking that data is correct after it has been entered. Validation Checks Range Check Checks data is within a certain range . Age: 34 203 Type Check Checks data is a certain data type . Height (in cm): 182 Two metres Format Check Checks data is entered in a certain way . Date of Birth (DD/MM/YYYY) 25/03/2001 25th March 01 Presence Check Checks that data has actually been entered and not left blank . Password: fluffythecat123 Lookup Table A table of acceptable entries , also known as a list . Length Check Checks the length of the input is within a certain amount. Telephone Number 08323877319 07383 Verification Checks Double Entry Typing in the data twice to make sure there were no spelling errors the first time. Password: fluffythecat123 flufythecat123 Proofreading Checking two copies of data to ensure they are exactly the same . Check Digit Similar to a checksum in a data packet, a check digit is calculated on barcodes to ensure the rest of the numbers are correct . Address: 11 Cherry Lane 11 Cherry Road Confirm Q uesto's Q uestions 8.4 - Validation & Verification: 1. Describe each type of validation check and give an example . a. Range Check [ 3 ] b. Type Check [ 3 ] c. Format Check [ 3 ] d. Presence Check [ 3 ] e. Lookup Table (List) [ 3 ] f. Length Check [ 3 ] 2. For the following data, suggest which validation check would be most suitable and why : a. Password [ 3 ] b. Country of Birth [ 3 ] c. Number of Tickets [ 3 ] d. Weight (in kilograms) [ 3 ] 3. Describe three types of verification check and give an example : a. Double Entry [ 3 ] b. Proofreading [ 3 ] c. Check Digit [ 2 ] 8.4 - Sorting & Searching Theory Topics 9.1 - IDE Tools

Learn about the benefits and drawbacks of virtualization, as well as about cloud storage and virtual clients. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 3.2 - Virtualisation Exam Board: OCR Specification: 2016 - Unit 1 What is virtualisation? Virtualisation is the creation of a virtual version of a device , software , operating system or server . These virtual versions can then be run on a different physical computer system , such as a powerful server . There are many different types of virtualisation . Storage virtualisation combines multiple separate storage devices into acting and appearing like a single , central storage system . Using storage virtualisation improves scalability as further devices can join the storage system if more space is required . It also simplifies the management of storage across the network. Server virtualisation allows one physical server to be divided into and host multiple virtual servers , each running separately . Each virtual server operates independently , handling its own operating system and applications . This allows for resources to be used more effectively and improves the scalability and versatility of the physical server . Client Virtualisation (Virtual Clients) Client virtualisation is when several virtual desktops are run on a single server - think back to the hypervisor from 3.1 . A virtual client is a full desktop environment where the processing happens remotely . For example, where an operating system is managed and hosted centrally but displayed locally on a different computer. These are often known as 'dumb clients ' because the server does the processing for it , meaning it can have minimal resources like a slow processor and little memory / storage . General Benefits & Drawbacks of Virtualisation Benefits of virtualisation: Costs are cheaper in the long-term because money is saved by not purchasing multiple physical devices . Money is also saved due to less cabling and lower power consumption . If set up efficiently, it can be used for higher performance at a lower cost - "Do more with less" . Programs can be tested in a secure environment before main-system deployment. Simplified response to recover after a disaster because only the server needs to be fixed. Drawbacks of virtualisation: If not set up efficiently, users could face serious performance issues , as fewer servers do more work. If a single physical system fails , the impact will be greater . Initial set up is complex , requires technical knowledge and can cost a lot. Easier for hackers to take more information at once as the data is stored in the same place. Benefits of client virtualisation: All data is stored in one central location , making backup and disaster planning easier to manage . The whole system can be managed , secured and updated from the server , rather than from each individual system. Hardware costs will be reduced because the virtual clients do not store or process their own data , meaning they can be of a low spec . Users can have multiple virtual machines and log in remotely (from anywhere with internet access ). Drawbacks of client virtualisation: Users will be unable to work if network connectivity is lost . There is a high strain on the server as the virtual clients do not store or process data themselves . An increased load on the server might result in poor performance for each client, especially with multiple connections . As the data is stored in one location , there are security risks of unauthorised access if the server is not adequately protected . Server Virtual Clients Cloud Technology 'The cloud ' is storage that is accessed through a network , primarily the internet. A cloud server is an example of storage virtualisation as data may be stored across multiple physical devices . There are three different types of cloud storage: Private cloud is where a business will have its own data centre that employees can access. This allows for flexible and convenient data storage and gives the business control over data management and security . Users of the private cloud will not usually have to pay individually for access - but the company will need to spend a lot of money on set up and maintenance . Public cloud uses third-party service providers such as Google Drive or DropBox to provide storage over the internet . Public cloud is usually a pay-for-use service , where businesses will pay for specific amounts that they need. Data management and data security is maintained by the cloud provider and the business is dependent on them providing constant access and deploying effective security measures. Hybrid cloud uses a mix of on-site storage (private cloud) and third-party (public cloud) services . Organisations can move workloads between private and public clouds as their specific needs and costs change . A benefit of hybrid cloud is that it gives an organisation greater flexibility and data storage options. As an example, a company could use on-site or private cloud storage to hold sensitive information and third-party, public cloud services to hold less important data . Q uesto's Q uestions 3.2 - Virtualisation: 1. What is the difference between server and storage virtualisation ? [ 2 ] 2a. What is a virtual client ? [ 1 ] 2b. What are the advantages and disadvantages of client virtualisation ? [ 8 ] 3. Explain any further general advantages and disadvantages of using virtualisation , not covered in your answer to 2b. [4 ] 4. Describe the differences between private , public and hybrid cloud storage. [6 ] 3.1 - Server Types Topic List 3.3 - Network Characteristics

Learn about how images are represented in a computer system, including file size, resolution, colour depth and metadata. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 2.4d: Image Storage Exam Board: OCR Specification: J277 Watch on YouTube : Pixels & Resolution Colour Depth & Metadata Image File Size Bitmap Images Bitmap images are made of pixels - single-colour squares - arranged on a grid . Each pixel is assigned a binary value which represents the colour of that pixel. The quality of a bitmap image depends on the total amount of pixels , this is known at the image resolution . Because it is made of pixels, scaling a bitmap image up will result in a visible loss of quality . Most images on computers are bitmaps, such as photos and screenshots . How to Calculate the File Size of a Bitmap File Size = Resolution x Colour Depth The resolution of an image is the width in pixels multiplied by the height in pixels. The colour depth (also known as bit depth ) is the number of bits that are used to represent each pixel's colour . 1 bit represents 2 colours (0 or 1 / black or white). 2 bits will allow for 4 colours, 3 bits for 8 colours, 4 for 16 etc. A colour depth of 1 byte (8 bits ) allows for 256 different colours . Remember you must multiply the colour depth , not the number of available colours (e.g. 8 not 256). The RGB (Red , Green , Blue ) colour model uses 3 bytes (a byte of 256 red shades , a byte of 256 green shades and a byte of 256 blue shades ) that together can represent 16.7 million different colours. Example Height = 6 bits Resolution = height x width Resolution = 8 x 6 = 48 bits -------------------------- Colour Depth = 1 bit (only 2 colours) -------------------------- File Size = Resolution x Colour Depth File Size = 48 x 1 = 48 bits File Size in bytes = 48 ÷ 8 = 6 bytes File Size in kilobytes = 6 ÷ 1000 = 0.00 6 kilobytes Width = 8 bits Look carefully at the exam question to see if the examiner is expecting the answer in bits, bytes or kilobytes . Always calculate the file size in bits first then: Divide the file size in bits by 8 to convert to bytes . Divide the file size in bytes by 1000 to convert to kilobytes . Metadata for Images Metadata is additional data about a file . Common image metadata includes: Height and w idth in pixels Colour depth Resolution Geolocation Date created Last edited File type Author details Metadata is important, For example, the dimensions must be known so the image can be displayed correctly . Metadata for a picture taken on a smartphone: width in pixels, e.g. 720 height in pixels, e.g. 480 Q uesto's Q uestions 2.4d - Image Storage: 1. Describe how bitmap images use pixels . [ 2 ] 2. Define the terms image resolution and colour depth . [2 ] 3. How many colours can be represented with a colour depth of... a. 1 bit [ 1 ] b . 5 bits [ 1 ] c. 1 byte [ 1 ] 4. How is the file size of an image calculated? [2 ] 5a. An image file has a width of 10 pixels , a height of 8 pixels and a colour depth of 2 . What is the file size in bytes ? [3 ] 5b. An image file has a width of 120 pixels , a height of 120 pixels and a colour depth of 1 . What is the file size in kilobytes ? [3 ] 5c. An image file has a width of 32 pixels , a height of 21 pixels and a colour depth of 1 . What is the file size in bytes ? [3 ] 6. State what is meant by metadata and give three examples of metadata for a graphics file. [ 3 ] 2.4c - Character Storage Theory Topics 2.4e - Sound Storage

Learn about secondary storage types such as solid-state, magnetic, optical and paper. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 1.2 - Storage Media Exam Board: OCR Specification: 2016 - Unit 2 Data can be stored on a variety of storage media , each with its own benefits and drawbacks . Magnetic Storage Optical 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. Hard disk drives can also be external and connected through a USB port . 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 . 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 Storage Characteristics: ✓ - Large CAPACITY and cheaper per gigabyte than solid state . X - Not DURABLE and not very PORTABLE when powered on because moving it can damage the device. ✓ - Relatively quick ACCESS SPEED but slower than Solid State . 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 . X - Optical discs have the Slowest ACCESS SPEED . Magnetic Disks are spelled with a k and Optical Discs have a c. Solid State Storage Paper 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 . SSDs can also be external . 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. Paper storage includes printed or hand-written documents, notes, forms, schedules and maps. Paper is relatively inexpensive in small quantities but it can take up a lot of space compared to small devices like USB sticks. Producing paper is environmentally damaging and requires physical security methods to keep safe. Paper, such as a timetable, can be written on if times change and easily carried on a person. However, paper in the form of an essay must be re-printed to add changes . Solid State Characteristics: ✓ - High CAPACITY but more expensive 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 . Paper Storage Characteristics: X - Low CAPACITY as each page can only hold a certain amount of information. Paper also takes up physical space . X - Poor DURABILITY as paper can easily tear and become damaged in rain. ✓ / X - PORTABILITY varies as single sheets of paper can be easily folded and placed in a pocket. However, large stacks of paper can be difficult and expensive to transport. X - Paper's ACCESS SPEED , in terms of searching for a specific item, is slow , especially if the paper storage has not been organised efficiently . Q uesto's Q uestions 1.2 - Storage Media: 1. State 3 examples of each type of storage media . For example, a CD for optical storage. [3 each ] 2. Compare each type of storage media in terms of capacity , durability , portability and access speed . You may decide to do this as a table or poster. [16 ] 3. Identify the most suitable device (not the media ) and justify its suitability for the following scenarios: a. Backing up a large database at the end of each day. [5 ] b. Keeping a copy of a cleaning schedule for hotel staff. [5 ] c. Making copies of a promotional video to hand out to audience members at a dancing event. [5 ] 1.1 - Holders of Information Topic List 1.3 - Access & Storage Devices

Learn how to create and use dictionaries in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 8C - Dictionaries Creating a Dictionary Dictionaries are used in Python to link items of data together . The example on this page uses a footballer dictionary which links a player with a team they played for. To define a dictionary, use curly brackets { } and separate linked data with a colon . A dictionary can be written on one line but the method below makes it easier to read: Printing Data from a Dictionary The first part of the linked data in a dictionary is called the key (e.g. each footballer in my example above). The second part of the linked data in a dictionary is called the value (e.g. each team). Example: key : value "Harry Kane" : "Tottenham Hotspur" A for loop can be used to cycle through each set of keys and values in the dictionary: Practice Task 1 a) Create a dictionary of your teachers and the subject they teach. b) Print their name and the subject they teach on each line. Example solution: Adding and Removing Data from a Dictionary Data can be added to a dictionary by stating the new key and value . You must use square brackets - [ ] The new data will be added to the end of the dictionary. You can print the whole dictionary to see any changes - e.g. print(playerdictionary) Data can be removed from a dictionary by stating the new key to remove in a pop command. You can print the whole dictionary to see any changes - e.g. print(playerdictionary) The whole dictionary can be cleared (reset to blank) using the clear command. Practice Task 2 a) Ask the user to enter a new teacher and their subject. b) Ask the user to remove a teacher. c) Print the list of teachers and check the new teacher has been added and the other one removed. Example solution: Searching Through a Dictionary An if statement can be used to check if a specific key is in a dictionary. If the key is in the dictionary then a message can be displayed using the key and the value . Otherwise, an else statement can output an appropriate response. To search for a value in a dictionary a for loop should be used to cycle through each key . If the value of each key matches the value that is being searched for then it will be printed. Practice Task 3 a) Create a search that allows a user to enter a teacher's name and prints the subject that they teach. b) Include an else statement to print a response if a teacher is not in the dictionary. Example solution: Changing Data & Copying a Dictionary The way to change values is similar to adding new data. The first input below is to determine the key and the second input determines the new value to be changed to. The copy command is used to make a duplicate of a dictionary . Practice Task 4 a) Create a copy of your teacher dictionary. b) Allow the user to enter a teacher and a new subject that they teach. c) Print the copy of the dictionary with the new values. Example solution: Using a Dictionary to Make a Game The code below is used to make a puzzle game where the user has to type in a footballer and the team they played for. I have added comments to explain the different parts of the code. A separate list has been created at the start to store the names of keys (players) that been correctly guessed . A while loop is used to constantly ask the user for players and teams. When they have guessed all 10 players (and the correct list reaches 10 ) the loop breaks and the game end. Instead of a further practice task here, Task 6 of the Section 8 Practice tasks page challenges you to make a similar game using a dictionary. ⬅ 8b - 2D Lists Section 8 Practice Tasks ➡

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 7 'Guess the Number' Multiplayer Game A primary school teacher wants to create a fun activity for their students to play when it is raining and they have to stay inside during break and lunch. Five pupils can play the game at once. Each player chooses a number between 1 and 100 . Then a random number is generated. Whoever was furthest from the random number is out of the game . The four remaining players then pick a new number . This continues with one player being removed each round until only one player is left and they are the winner. Add your own flair and additional features to your program as an extension, including preventing the same number being chosen by multiple players . 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. Reminders for this task: You will need to use loops to allow the users to enter their numbers. You may wish to use subroutines to decompose the problem into separate rounds. You will need to import the random library to generate a random number in each round. You will need to compare each number to the randomly selected answer using comparison operators such as > and <. There are multiple ways to approach this program, and your solution might look different from the example. Break the problem down and focus on one part at a time. Example solution: Introduction & Round One Round Two ⬅ Extended Task 6 (Word Game)

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