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Learn about ethical, legal, cultural, privacy and environmental impacts of digital technology. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 6.1a: Impacts of Technology Exam Board: OCR Specification: J277 Watch on YouTube : Impacts of Technology What are the issues created by technology? As the use of computers and technological devices continues to rise every year, this increase brings with it a range of different types of issues . Categories of issues described on this page include: Cultural issues Environmental issues Ethical issues Legal & Privacy issues Cultural Issues Culture relates to society and how different parts of the world vary in terms of computer and internet usage . The Digital Divide This term relates to the gap between those people who have access to modern digital technology (such as computers and the internet) and those who have limited access . 'Limited access' could be devices at home or shared devices or having lower-performance (cheaper) computers and low-speed internet connections. The digital divide can be seen in different ways , such as: People in cities vs. People in rural areas . Younger people vs. Elderly people. Developed countries vs. Developing countries. The digital divide is an important ethical issue because digital technologies have led to numerous international benefits including boosted growth , improved product delivery , enhanced communication and increased opportunities . However, this impact is uneven and these positive impacts are mostly occurring in technologically-advanced regions such as North America , Western Europe and Japan . Regions like some nations in Africa and Central Asia have limited digital infrastructure and government instability , leading to poor internet speeds , high costs and limited resources . Discussion Points: What do you think can be done to bridge the digital divide? Whose job is it to bridge the gap? Who will pay for the technology? Changes to Work The internet , the development of new technologies such as cloud storage and increased video communication have transformed the way that many businesses operate across the world. Staff may be able to work from home or access documents collaboratively outside of the traditional workplace, such as cafes or on public transport. Some jobs have moved abroad to save costs, such as help centres for online issues. Tasks can be outsourced to freelancers in other countries where people are content to be paid less for their time and services. For example, some companies will hire temporary web developers from countries such as India to work for them for a lower salary than local workers. Another change to work that technology has brought is the loss of jobs , especially low-skilled jobs such as factory workers that have seen their roles replaced by technology and automation . However, technology has also created millions of new jobs , including installing and maintaining the machines that replace other roles. Environmental Issues Environmental issues concern the natural world and the negative effects of producing , using and discarding computer systems and devices. Energy and Material Consumption In the past 30 years, the number of technological devices has increased astronomically and thousands of new devices are manufactured each day . These devices need to be assembled using a range of materials , including plastics , metals and some rarer elements and need a considerable amount of electrical power to run. Certain systems like web servers and data centres must be powered on all day , every day, which uses a large amount of energy . Pollution and Waste Generating the electricity to power computers creates pollution - an average PC could require up to 50% more energy per year than a fridge. Computers are difficult to recycle and discarded components can lead to land, water and air pollution due to harmful materials , such as lead and mercury , leaking into the environment. Smartphone trends are also negative for the environment as new devices are released yearly , with minor upgrades that people buy to appear fashionable and up-to-date. To lessen the environmental impact, people should reuse and recycle their devices. Ethical Issues Ethics relates to what is considered right or wrong . Often this is subjective - people may have differing opinions on the issue. Drones Uses of drones: Filming and photography for television, movies and special events. Monitoring pollution levels in the atmosphere. Tracking and monitoring wildlife , such as rhino populations in Africa. Disaster zone response , such as searching for survivors following an earthquake. Delivery companies are developing drones to quickly deliver goods across cities. Drones are used by the military to target sites in other countries, such as American soldiers deploying surveillance drones in Syria. Discussion Points: Should you need a licence to buy and fly a drone? Should drones be used to monitor the public? Like flying CCTV? Should drones be used to deliver items? Like Amazon packages? If a drone hits a plane and it crashes, what should the punishment be? A drone is an unmanned aerial vehicle (UAV ) that is remotely operated and can be used for a wide range of purposes. Self-Driving Cars Self-driving cars (also known as autonomous vehicles ) are currently in the development and testing stage with companies like Tesla and Amazon. Benefits of self-driving cars include: In theory, driving will be safer because cars are less likely to make mistakes that humans do and they can’t become distracted or tired . Self-driving cars should be more fuel-efficient because they take the most direct route to destinations and do not get lost. ‘Drivers’ in the car can perform other tasks instead of driving, such as work or planning. Autonomous vehicles could include trucks and vans to automate the delivery and freight industries . Trucks could drive overnight to deliver goods whereas currently, human drivers must take breaks every few hours. Drawbacks of self-driving cars include: Cars could still crash as code and software processes may fail. The technology is still in development and will be very expensive for the first few years when self-driving cars are available to purchase. Jobs may be lost such as delivery and truck drivers whose vehicles are equipped with self-driving technology. Other industries like motorway services and hotels may also be affected. Discussion Points: Would you trust a car to drive itself? Who is to blame if a self-driving car crashes? The car maker? The people in the car? The software writers? What should happen to the people whose jobs are taken by self-driving vehicles? Artificial Intelligence Artificial Intelligence (AI ) is the act of computers replacing humans to analyse data and make decisions . In recent years AI has become more common in the home and on devices like smartphones; assistants such as Siri and Alexa are prime examples of modern home AI. AI Chatbots like ChatGPT have become more popular in recent years but have lead to issues such as plagiarism , misinformation and breaking copyright laws . The weather today is cloudy. Benefits of AI include: Processes are sped up as computers can analyse large amounts of data much quicker than a human. AI can be used when a human is unavailable , such as using a symptom checker on the internet for a minor illness rather than booking and waiting for a doctor. Repetitive or time-consuming tasks can instead be completed by a computer , such as searching and sorting scientific data or generating ideas , images or audio from a prompt . Drawbacks of AI include: AI can store and process a lot of personal data , especially personal assistants like Alexa which are always listening for ‘wake words’. This data can be viewed by the company that develops it and could be hacked by attackers. AI is programmed by humans and mistakes in code could have disastrous consequences if the AI is used to make important decisions , such as military deployment. AI GPT tools like ChatGPT can give incorrect results , may use copyrighted material in their response and students may use it to submit work that is not their own . Discussion Points: If a robot harms a human who is to blame? The robot? The programmer? The manufacturer? Us? Would you trust a walking, talking robot assistant in your home? Should ChatGPT be banned in schools or can it be helpful? Should AI make decisions for us? Legal & Privacy Issues Legal and privacy issues regard laws that have been introduced by the UK government to protect data, systems and networks from unauthorised access . See 11.2 for explanations about important computing legislation in the UK. Loss of Privacy & Hacking There has been a lot of criticism in the last few years about how internet companies and governments are using personal data to invade privacy and track civilians . Facebook was involved in a scandal with using personal data for reasons that were not the original intention. In reverse, WhatsApp and Apple have been criticised for encrypting messages sent by terrorists that police have been unable to track and read. Every week a new company seems to announce that its data has been hacked . Attackers are constantly using botnets and infected systems to crack poorly secured databases and attempting to phish individuals for usernames and passwords. In the past few years, major hacking breaches include Sony, Yahoo and TalkTalk. Discussion Points: Should the UK government be able to see the websites you have visited in the last year? What should happen if a major company is hacked and bank details are stolen? Should they be fined? Pay customers? Prison? Should WhatsApp allow authorities to access encrypted messages? What if they know a terrorist is using it to communicate? Should the UK debate privacy laws before they go into place? Online Crime Unlawfully obtaining personal information and using it for identity theft or fraud . Harassment and threatening others on social media or private messages; blackmail . Cyber attacks are more common - see 3.8 for information about DOS attacks , IP spoofing , SQL injection and more. Sharing copyrighted material such as television programmes, music and video games. Distributing prohibited material such as drugs or weapons on the dark web. See 6.1b for explanations about different laws that have been created to tackle online crime . The increased popularity of the internet and the rising number of users has led to a wave of online crime , taking many different forms, including: Q uesto's Q uestions 6.1a - Impacts of Technology: Cultural Impacts 1a. What is the digital divide ? [ 2 ] 1b. Describe 2 examples of how the digital divide can be seen . [ 2 ] 2. Describe in detail 3 ways that technology has changed the way people work . [9 ] Environmental Impacts 1. Describe the different ways that the increasing use of technology negatively impacts the environment . [ 5 ] Ethical Impacts 1a. What is a drone ? [1 ] 1b. Make a list of all of the positive impacts and the negative impacts of using drones . You should have at least 3 on each side. [ 6 ] 2. Describe 2 benefits of using self-driving cars and 2 negative consequences . [4 ] 3. Describe how artificial intelligence can be used for good . [ 4 ] Legal & Privacy Impacts 1. A hack on a bank has occurred. Describe what you think the impacts would be on the following groups of people: a. The customers . b. The bank managers . c. The general public . [ 6 ] 2. Describe 4 different types of online crime . [ 8 ] 5.2 - Utility Software Theory Topics 6.1b - Legislation

Learn about how sounds are represented in a computer system including how analogue sound waves are converted into binary. Also, learn about sample rate, bit depth and metadata. Based on the 2020 Eduqas (WJEC) GCSE specification. 4.7: Sound Representation Exam Board: Eduqas / WJEC Specification: 2020 + Converting Analog Sound to Binary To store sound on a computer analog sound waves must be converted in to digital data ( binary ). The sound is sampled using an ADC (Analog to Digital Convertor) and stored as a binary value (such as 01010011) called a sample . 0010 1011 0101 0101 Analog sound wave ADC (Analog to Digital Converter) Binary sample Sampling an Analog Sound Wave Digital sampling is discrete (separate) and not continuous like analog waves. To get the highest quality sound, many samples are taken to recreate the analog wave as closely as possible . Sample Rate The sample rate is the number of samples taken per second . It is measured in kilohertz (kHz), for example CD quality is 44.1kHz (44,100 samples per second). The higher the sample rate , the better the audio quality as the digital data more closely resembles an analog wave . However, higher sample rates result in larger file sizes because more data is stored for each individual sample. A low sample rate will result in a low-quality sound because the digital data does not closely resemble the original analog wave . A higher sample rate will result in a higher-quality sound because the digital data more closely resembles the original analog wave . Improving Audio Quality Bit Depth Bit Rate The bit rate is defined as the amount of audio data processed per second . It is measured in kilobytes per second (kbps ). The bit rate is calculated by multiplying the sample rate and bit depth . Because the bit rate is the measure of the sample rate and bit depth multiplied together, the higher the bit rate the higher the quality of the sound . The bit depth is the number of bits available to represent each sample . For example, a sample with a bit depth of 4 could be 0101 or 0111 or 1010. A sample with a bit depth of 8 could be 01010110 or 1010110 or 11001111. A common bit depth is 16 bits . The higher the bit depth , the more bits are available to be used for each sample. Therefore the quality is often higher as the wave more closely resembles an analog wave . The file size will also be larger if the bit depth is higher, as each sample stores additional bits . Example: A short audio sample has a bit depth of 4 and a sample rate of 10 samples per second . The clip is 15 seconds long . Calculate the bit rate by multiplying the sample rate and bit depth : 4 bits x 10 = 40 bits . Now that is the correct data for one second. Multiply the bit rate by the number of seconds in the file: 40 x 15 = 600 bits . To convert the answer from bits to bytes , divide by 8 . 600 bits ÷ 8 = 75 bytes . Calculating File Size Metadata for Sound Files Music libraries such as Apple Music or Spotify store a huge amount of metadata on each song. Metadata is additional data about a file such as: Artist Title / Track Title Product / Album Title Track Number Date Created / Year Genre Comments Copyright Software Type Duration File size Bit rate Sampling rate Channels Volume Q uesto's Q uestions 4.7 - Sound Representation: 1. Explain how an analog sound wave is converted into a binary sample . [ 2 ] 2a. What is a sample rate ? [1 ] 2b. Explain two ways an audio file will be affected if the sample rate is increased . [4 ] 3a. What is bit depth ? [2 ] 3b. Explain two ways an audio file will be affected if the bit depth is increased . [4 ] 3c. Explain what the bit rate is. [ 2 ] 4 . An audio sample has a bit depth of 8 , a sample rate of 10 and it is 12 seconds long . What is the file size in bytes ? [ 2 ] 5a. What is metadata ? [ 2 ] 5b. State four different types of metadata for audio files . [4 ] low bit rate = lower quality high bit rate = higher quality Converting Analog Sound to Binary 1 4.6 Graphical Representation Theory Topics 4.8 - Compression

Learn about two important expansion cards that can be connected to the motherboard - graphics cards and sound cards - and how they work. Expansion Cards PCI slots What are expansion cards? Expansion cards are additional components that you plug into the motherboard’s expansion slots to add or enhance features . The slots are called PCI (on older computers ) or PCIe (on newer models ). Common types are graphics cards (video ), sound cards (audio ), network cards (internet ) and capture cards (streaming ). Graphics Card A graphics card processes images , videos and 3D graphics so they look smooth and realistic . It is used for gaming , video editing , 3D modelling and Virtual Reality (VR ). It has its own processor - the Graphics Processing Unit (GPU ) - and dedicated memory (VRAM ), so it doesn’t overload the CPU or RAM . Modern graphics cards can also handle tasks like artificial intelligence (AI ) and bitcoin mining . Graphics cards usually have a cooling system, like a fan , so it doesn't overheat. The graphics processing unit ( GPU ) is a chip that renders images and video. The graphics card has ports such as HDMI or DisplayPort to connect monitors or TVs. The PCIe connector allows the graphics card to slot onto the motherboard. Sound Card The DAC ( Digital-to-Analogue Converter ) converts digital data (1s and 0s) from the computer into analogue sound waves for speakers/headphones. The ADC ( Analogue-to-Digital Converter ) converts analogue input (like voice from a microphone) into digital data the computer understands. Jacks are small round sockets where you plug in audio devices like headphones, microphones, or speakers. The PCIe connector allows the sound card to slot onto the motherboard. A sound card improves the quality of audio input/output compared to the motherboard’s built-in sound . They are not needed by most users , because of the motherboard's built-in sound , but they are used by music production , gaming or professional audio work . It can support surround sound systems , high-quality microphones , and musical instruments using jacks (audio ports ). Integrated cards Built directly into the motherboard . Cheaper , uses less power and is good enough for basic tasks (e.g. web browsing , watching videos and office work ). Shares the computer’s RAM and processor (CPU ) instead of having its own . An example is integrated graphics on a laptop for browsing and schoolwork . Dedicated cards These are separate expansion cards (e.g. graphics card or sound card ) to connect to the motherboard 's PCIe slots . They usually have their own processor and memory (e.g. GPU & VRAM for graphics ). Much more powerful , ideal for gaming , video editing , 3D design or professional audio . Uses more power and costs more . KS3 Home

Learn about visual design elements of human-computer interfaces such as colours, interaction, location hierarchy, messages (help, error) and typography (style, size). Based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced National in Computing (H029 / H129) (AAQ - Alternative Academic Qualification). Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F160: Fundamentals of Application Development Certificate: Computing: Application Development (H029 / H129) 5.2 - Human Computer Interface Visual Design Considerations Watch on YouTube : Visual design considerations When creating a human-computer interface , there are several visual design considerations that the development team must take into account, such as the use of colour and the style of typography . You need to know how each visual design consideration is used when designing human-computer interfaces and how these interfaces can be improved to be more effective . As with most topics, it is also vital to consider how client requirements may impact changes related to visual design , for example, using larger text for users with visual impairments . Visual Design Considerations Visual Design Considerations Colours are used to define the visual appearance of the interface . This includes background colours , button colours , icons and text . Interaction refers to how users control or respond to the system through input methods like clicking , tapping , swiping , typing or speaking . Location hierarchy is about the placement and organisation of interface elements based on importance . Messages are displayed to provide feedback , guidance or explanations - such as confirming actions , explaining errors or offering help . Typography includes the choice of font types and the size , spacing , weight (boldness) and alignment of text . Q uesto's Q uestions 5.2 - Human-Computer Interface Visual Design Considerations: 1. Explain how colours can be used effectively in human-computer interfaces . [4 ] 2. Describe what is meant by location hierarchy and why it is important to consider . [4 ] 3. Suggest specific visual design considerations an application developer should consider when making software for a primary school in Dubai . [ 5 ] Approximately 1 in 12 men and 1 in 200 women are colour-blind , meaning good designers should include text or icons rather than relying on just colour to convey meaning . D id Y ou K now? 5.1.2 - Types of Devices Topic List 5.3 - HCI Designs & Diagrams

Learn about pseudocode, procedural programming, big O notation (constant, linear, polynomial (quadratic), exponential, linearithmic and logartihmic) and the complexity of different data structure, sorting and searching algorithms. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level Specification: Computer Science H446 3.1a - 3.1d - Algorithm Complexity Watch on YouTube : Pseudocode Procedural programming Big O notation Algorithm complexity Pseudocode Pseudocode is a simplified , language-independent way of writing algorithms that looks like programming but uses plain English to describe the steps clearly without worrying about exact syntax . The OCR A-Level Computer Science course uses a form of pseudocode unique to the exam board called 'OCR exam reference language ' that all code in exams will be written in . OCR exam reference language uses closing commands such as endif for an if statement and endwhile for a while loop . It also uses the word then instead of a colon like in Python . YouTube video uploading soon Procedural Language A procedural language , such as Python or Java , is a programming language that structures programs as sequences of step-by-step instructions grouped into procedures or functions . It focuses on breaking tasks into smaller , reusable blocks of code that operate on data , making programs easier to write , understand and maintain . This topic is in both Paper 1 and Paper 2 . YouTube video uploading soon Big O Notation O(n) Big O Notation is a way of describing how the time complexity (how long an algorithm takes ) and space complexity (how much memory it uses ) grows as the size of the input increases . This allows algorithms to be compared in terms of efficiency , using the letter n to refer to the size of the input . Complexity types: Constant - O(1) - The algorithm’s time or space stays the same no matter how large the input is . Linear - O(n) - The time or memory grows directly in proportion to the size of the input . Polynomial - O(n²) - The growth increases in proportion to the square of the input , often seen in algorithms with nested loops . Exponential - O(2ⁿ) - The time or memory doubles with each additional input element , becoming extremely slow very quickly . Logarithmic - O(log n) - The algorithm’s time grows very slowly as the input size increases , often achieved by repeatedly halving the data . Linearithmic - O(n log n) - A combination of linear and logarithmic behaviour, common in efficient sorting algorithms like merge sort . YouTube video uploading soon Algorithm Complexity Best-case , average-case and worst-case complexity describe how an algorithm performs under different input conditions . Best-case complexity is the time or space required when the algorithm meets the most favourable input , allowing it to finish as quickly or efficiently as possible . Average-case complexity represents the expected performance across typical or random inputs , giving a realistic view of how the algorithm behaves in normal use . Worst-case complexity is the maximum time or space the algorithm could ever require , used to guarantee performance even in the least favourable situation . Sorting and searching algorithms often have different case complexities for time and space . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Pseudocode Procedural Language: input, output, comments, variables, casting, count-controlled iteration, condition-controlled iteration, logical operators, selection, string handling, subroutines, arrays, files Big O Notation: time complexity, space complexity, constant, linear, polynomial, exponential, logarithmic, linearithmic, best-case, average-case, worst-case D id Y ou K now? Minecraft doesn’t load the entire world at once ; instead, it divides the world into chunks and only generates or loads the chunks near the player . Finding , saving and retrieving these chunks uses data structures like trees and hash maps , which allow the game to look up a chunk in about O(log n) or even O(1) time , minimising lag even in large worlds . 2.2 - Computational Methods A-Level Topics 3.1e - Data Structure Algorithms

Learn about the two types of language levels, high level and low level, including explanations and examples. Based on the 2020 Eduqas (WJEC) GCSE specification. 7.1: Language Levels Exam Board: Eduqas / WJEC Specification: 2020 + There are two types of programming languages used within computer systems: High-Level Languages Why do programmers use high-level languages? H igh-level programming languages use code written in a way that is similar to a natural human language , such as English, making it easier to understand and use the language. Using high-level languages leads to fewer errors and allows for more powerful and complex commands compared to low-level languages. However, a high-level language must be translated into machine code (binary) before it can be run, as high-level languages cannot be executed directly by the CPU . Popular high-level languages: PYT HON C++ Ja v a Visual Basic Low-Level Languages Low-level languages do not closely resemble a natural human language , making it harder for humans to understand and write in. Low-level languages are used when a program must be executed quickly or when programmers need to write code that interacts directly with the hardware , such as device drivers. There are two types of low-level language : Machine Code This is the pure binary code that computers can directly process and execute . It is extremely tedious and difficult for humans to understand and write machine code. However, machine code can be used when a programmer needs to perform a very specific command that can't be done in a high-level language. Machine code will be executed faster than high-level programs because it is already in a format the CPU can execute and does not need to be translated . 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 0101 0100 1010 1010 1010 1010 1111 1110 0010 1001 0100 1001 0010 0111 0111 0101 0011 1010 1000 0101 0110 0111 0000 1010 1010 0011 1101 1001 0010 1101 0010 0100 1001 0011 1010 1001 0101 0101 0010 0101 0111 0101 0101 1000 1011 0111 Assembly Language Assembly language uses specialised command mnemonics to perform actions . See the Assembly Language section in the programming tab for a list of mnemonics such as INP , OUT and HLT . Assembly language is preferred by many programmers over machine code because it is easier to understand and spot errors . It is faster to execute than high-level languages and, like machine code, can be used to directly control the CPU . Q uesto's Q uestions 7.1 - Language Levels: 1a. Describe three reasons why programmers use high-level languages . [ 3 ] 1b. Explain one limitation of using high-level languages . [2 ] 2a. Describe a key difference between low-level languages and high-level languages . [ 2 ] 2b. Describe when a low-level language would be used instead of a high-level language . [2 ] 2c. Describe an advantage and a disadvantage of writing directly in machine code . [2 ] 2d. Describe what assembly language is. Give one benefit to using assembly language instead of machine code and one benefit to using it instead of a high-level language . [3 ] 3. Compare high-level and low-level languages by stating which is: a. Easier to understand [ 1 ] b. Requiring translation [ 1 ] c. Quicker to execute [ 1 ] INP STA Number1 OUT HLT Number1 DAT 6.2 - Utility Software Theory Topics 8.1 - Programming Principles

Learn about the role of different server types including file, application, print, email, mail servers and the hypervisor. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 3.1 - Server Types Exam Board: OCR Specification: 2016 - Unit 1 What is a server? A server is a powerful dedicated system on a network . It requires increased memory , storage and processing power than traditional computer systems to fulfill its role across the network. Servers need to be scalable - this means they must be adaptable and able to efficiently manage the needs of connected systems if more are added or some are removed . Servers have different roles so a company may use multiple , separate server types within their organisation, each with a specific purpose . Having separate servers is costly but beneficial as if one loses connection , others may still be usable . Also a server will be more efficient if it is only managing one resource (e.g. printers) at a time . File Server A file server centrally stores and manages files so that other systems on the network can access them. The server provides access security , ensuring that only users of the appropriate access level can access files. File servers can be used to automatically backup files , as per the organisation's disaster recovery policy. Using a file server frees up physical storage space within a business and can provide printing services too. Printer Server These servers control any printers on a network and manage printing requests by sending the document to an appropriate printer. Print servers use spooling to queue print jobs so that they are printed when the printer is ready. If a fault occurs with a certain printer, work can be automatically diverted to another available printer. Application Server These servers allow users to access shared applications on a network. All users will be able to access common applications like email software or word processing, but the server will also restrict certain applications to those with invalid access levels (such as hiding financial databases from employees outside of the finance department). Application updates can be simply deployed to the application server only , avoiding individual updates for each system and saving a lot of time . Installers can be hosted on an application server, allowing the software to be easily installed on other connected machines . Database Server These servers manage database software that users on the network can access and use to manipulate data . Data held on the server will be stored in a database accessible from multiple connected computers . The data can be modified using query languages such as SQL. Storing data on a database server, rather than individual computers, is more reliable . A database server for a business also allows for scaling - for example, the database can be increased in size if the customer base grows. Web Server A web server manages HTTP requests from connected devices to display web pages on web browsers . A request (e.g. csnewbs.com) is sent to the web server. The server contains a list of known URLs and their matching IP addresses . The server contacts the server where the web page is held and delivers the web page to the client . Mail Server These servers send and receive emails using email protocols (SMTP & POP) allowing email communication between other mail servers on other networks. The server makes sure emails are delivered to the correct user on the network. Email servers can store company address books making internal communication easier for organisations. The server may have anti-spam functions to reduce junk mail. Hypervisor A hypervisor allows a host machine to operate virtual machines as guest systems. The virtual machines share the resources of the host , including its memory, processing power and storage space. This type of technology is called virtualisation . The guest machines are isolated so if one failed, the other guests and the hosts are not affected - demonstrating good security . The hypervisor optimises the hardware of the host server to allow the virtual machines to run as efficiently as possible. Q uesto's Q uestions 3.1 - Server Types: 1a. What is a server ? Why does it need to be scalable ? [2 ] 1b. Give two reasons why a company may use multiple , separate servers . [2 ] 1c. State the 7 types of server . [1 each ] 2. A medium-sized animation company working on a movie are considering buying a server. Describe each type of server and the different roles they have. a. File Server b. Printer Server c. Application Server d. Database Server e. Web Server f. Mail Server g. Hypervisor [4 each ] 3. What type of technology does a hypervisor use to control multiple virtual machines? [1 ] 2.7 - Protocols Topic List 3.2 - Virtualisation

Learn about the three types of translators - assemblers, interpreters and compilers. Also, understand the differences between compilers and interpreters. Based on the 2020 Eduqas (WJEC) GCSE specification. 10.1: Translators Exam Board: Eduqas / WJEC Specification: 2020 + What is a translator? A translator changes (translates) a program written in one language into another language (usually machine code ). There are three types of translator : Assembler An assembler converts low level assembly language into machine code . INP STA 33 INP STA 34 LDA 33 ADD OUT HLT Interpreter An interpreter converts high-level language one line at a time into machine code and executes it. PYT HON Compiler A compiler converts high-level language into machine code for execution at a later time. The entire program is converted at once . PYT HON 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 Differences between an interpreter and a Compiler: Interpreter Compiler Execution Method: An interpreter translates source code (high level code) into machine code one line at a time . Execution Speed: An interpreter is slower than a compiler because the code must be reinterpreted each time the program is run. Complexity: Interpreters are smaller, simpler programs . Error Reporting: In error reporting, the interpreter would encounter the errors and report it to the user immediately and stops the program from running. Repetition: Interpreted programs can be edited and run without translating the whole program . Interpreters must reinterpret the program every time it is run. Execution Method: A compiler translates all the source code (high level code) into machine code in one go . A compiler produces an executable file that will run on other machines without the compiler needing to be installed. Execution Speed: Compilers can produce much more efficient code than interpreters making the compiled programs run faster . Complexity: Compilers tend to be large complex programs . Error Reporting: The compiler would analyse the entire program , taking note of where errors have occurred and record them in an error file . Repetition: Compilation requires analysis and the generation of the code only once , whereas interpreters must re-interpret each time. However, compiled programs have to be re-compiled after any changes have been made. x1 ∞ x1 Q uesto's Q uestions 10.1 - Translators: 1. Briefly describe each type of translator : a. Assembler [ 1 ] b. Interpreter [ 2 ] c. Compiler [ 2 ] 2. Compare interpreters and compilers for each of the following features : a. Execution Method b. Execution Speed c. Complexity d. Error Reporting e. Repetition [ 10 total ] 9.1 - IDE Tools Theory Topics 10.2 - Stages of Compilation

Learn about the differences between wired and wireless networks. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 3.2a: Wired & Wireless Networks Exam Board: OCR Specification: J277 Watch on YouTube : Wired Networks Wireless Networks Encryption Wired Connections Wireless Connections Wireless connections, such as WiFi or Bluetooth , use no cables but require a wireless network interface card (WNIC ). Wireless connections generally have a slower speed and can be affected by the computer's distance from the wireless router as well as obstacles like walls or bad weather. Wired connections use physical cables , such as copper or fibre optic wires , and require a network interface card (NIC ) to connect to a network. These wired connections use a wired connection protocol - most commonly Ethernet . Restricted Movement Faster More Secure NIC Required Freedom of Movement Slower Less Secure WNIC Required Encryption Wireless connections are less secure and require encryption . Encryption is the process of scrambling data into an unreadable format so that attackers cannot understand it if intercepted during transmission. The original data (known as plaintext ) is converted to scrambled ciphertext using an encryption key . Only at the correct destination will the encryption key be used to convert the ciphertext back into plaintext to be understood by the receiving computer. Q uesto's Q uestions 3.2a - Wired & Wireless Networks: 1. Briefly compare wired and wireless networks in terms of movement , transmission speed , security and required hardware . You could answer this in the form of a table. [ 8 ] 3.1b - Network Hardware & Internet Theory Topics 3.2b - Protocols & Layers

Learn about protocols including FTP, HTTP, POP, SMTP, SNMP, TCP, UDP, ICMP, IP and the TCP/IP stack. Resources based on Unit F161 (Developing Application Software) for the OCR Cambridge Advanced Nationals in Computing (H029 / H129) AAQ (Alternative Academic Qualification). Qualification: Cambridge Advanced Nationals in Computing (AAQ) Certificate: Computing: Application Development (H029 / H129) Unit: F161: Developing Application Software 3.2 - Protocols Watch on YouTube : Protocols TCP/IP Stack You need to know the role and uses of specific common protocols (FTP , HTTP , POP , SMTP , SNMP , TCP , UDP , ICMP , IP ). You also need to understand the structure , content and use of the 4-layer TCP/IP stack . What You Need to Know Common Protocols ? YouTube video uploading soon TCP/IP Stack ? YouTube video uploading soon Q uesto's Q uestions 3.2 - Protocols: 1. What? [2 ] 2. What? [1 ] 3. What? [1 ] 4. What? [1 ] ? D id Y ou K now? 3.1 - APIs Topic List 4.1 - Security Considerations

Learn about what embedded systems are and examples of them. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 1.3: Embedded Systems Exam Board: OCR Specification: J277 Watch on YouTube : Embedded Systems Example: A washing machine has a control chip that manages the different program cycles. An embedded system is a computer system built into a larger machine to provide a means of control . Embedded systems perform a specific pre-programmed task which is stored in ROM . An embedded system uses a combination of hardware and software . They perform only specific tasks and often have a small amount of storage and low processing power . Example: A traffic light has a control chip that determines when to change to a green or red light. Q uesto's Q uestions 1.3 - Embedded Software: 1. What is an embedded system ? [3 ] 2a. Give two examples of an embedded system. [ 2 ] 2b. Research and describe another two examples of an embedded system. [ 4 ] 1.2 - CPU Performance 2.1 - Primary Storage Theory Topics

Learn about defensive design considerations including validation checks, verification, anticipating misuse, maintainable code, authentication and input sanitisation. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 3.1: Defensive Design Exam Board: OCR Specification: J277 Watch on YouTube : Defensive Design Validation Checks Maintainability Defensive Design Considerations There are several things to consider when creating a program that is secure and robust , including: Anticipating Misuse Planning ahead to take steps against potential misuse (e.g the app X prevents the same tweet sent twice in a row as it might be spam ). Input Sanitisation Checking and cleaning up data that has been input , (e.g. removing special characters to prevent a SQL injection ). Validation Checking whether input data follows specific criteria and should be accepted (e.g. a length check on a password). Verification Checking whether data that has been entered is correct (e.g. double entry ). Authentication Ensuring only authorised users can gain access to a system (e.g. usernames and strong passwords ) . Maintainable code Allowing other programmers to easily read and quickly understand code that has been written (e.g. using comments , indentation and appropriate variable names ). Input Validation Validation is a process to check that data is reasonable or sensible before it is accepted . 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) 25/03/2011 25th March 11 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 Maintainability Programs should be written in a way that makes maintaining and understanding them as straightforward as possible. Examples of making a program maintainable include: Using subprograms to reuse code and make them easier to test . This is called modularisation . Appropriate variable names , using a naming convention , ensure the purpose of a variable is immediately understood. Using indentation to improve readability and clearly show each ‘block’ of code. Comments enable a programmer to understand the purpose of each line of code. Crucial when working in a team . Using constants is another method of improving maintainability. This keeps the program code consistent , which makes it easier to read and debug a program. Q uesto's Q uestions 3.1 - Defensive Design: 1. Describe the different considerations a programmer should make for a defensive design . [ 6 ] 2. Describe the each validation check and give a suitable example . [ 12 ] 3. Explain the different ways a program can be maintained . [ 5 ] 2.3 Additional Programming Theory Topics 3.2 - Testing