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Learn about methods of wired and wireless connections to transmit data on the internet, including satellite and bluetooth. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 1.4 - Internet Connections Exam Board: OCR Specification: 2016 - Unit 2 The internet i s a global network of interconnected networks . There are multiple methods of connecting to the internet . Wired Connections Copper Cables Copper cables are a cheaper type of wired internet connection that may be poorly insulated and therefore susceptible to electromagnetic interference . Copper cables are more likely to suffer from attenuation (network distortion ). However, they are malleable (easier to bend) and less likely to break than other cables such as fibre optic. They have a lower bandwidth - cannot transmit as much data at once - than fibre optic cables. Fibre Optic Cables Fibre optic cables are a very fast but expensive type of wired internet connection. Signals are transmitted as waves of light through a glass tube. Because of this fibre optic cables are not affected by electromagnetic interference and suffer less from attenuation . Fibre optic cables have a higher bandwidth - can transfer more data at one time - than copper cables but they are more fragile . Wireless Connections Bluetooth Bluetooth is a temporary short-range communication between devices within a limit of about 10 metres . For example, Bluetooth can be used to transfer audio files from one smartphone to another. The close proximity is a disadvantage but no other hardware is required for a connection. Microwave Microwave connections use radio waves to send signals across a large area via microwave towers . It can transmit a large amount of data but antennas must be in the line of sight of each other with no obstructions . Microwave connections are affected by bad weather , leading to higher chances of attenuation (network distortion ). Satellite Satellite networks use point-to-multipoint communication by using satellites above the Earth's atmosphere that receive a transmission and rebroadcast them back to Earth. Because of the distance between the communication device and the satellite (roughly 45,000 miles), there is a delay between data transmission and it being received. GSM / 5G GSM (Global System for Mobile communications ) is a technology for allowing mobile phones to connect to a network for calls and text messages. Advances in mobile technology are classified by generations such as 4G and 5G (the current generation). Each generation is generally faster, more secure and allows for new opportunities. Connection Characteristics When connecting to the internet there are several characteristics that a user must consider: Strength Range Latency Bandwidth Storage Capacity Contention Latency is the delay when sending data across a network. Bandwidth is the maximum amount of data that can be sent across a network at once . Contention refers to whether a network is dedicated ( uncontended ) or shared between users ( contended ). Q uesto's Q uestions 1.4 - The Internet: 1. Compare the differences between copper and fibre optic cables (possibly in a table) by the following features: a. Price b. Bandwidth c. Interference d. Attenuation e. Malleability / Fragility [2 each ] 2. Describe each of the different types of wireless connection . Try to list 1 advantage and 1 disadvantage of using each type. a. Bluetooth b. Microwave c. Satellite d. GSM / 5G [5 each ] 3a. State the 6 characteristics of a network. [6 ] 3b. Describe what is meant by the following characteristics : i. Latency ii. Bandwidth iii. Contention [1 each ] 1.3 - Access & Storage Devices Topic List 1.5 - WWW Technologies

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

Learn about 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 network operating systems, open source operating systems and proprietary operating systems. Resources based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced Nationals 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) 1.2 - Operating Systems Watch on YouTube : Network Operating System Open Operating System Proprietary Operating System An operating system is software that manages the resources of a computer system , such as memory , users and files . It also provides a user interface so that humans can interact with the device's hardware . An operating system allows application software to be opened and run . There are three types of operating system that you need to know - network , open and proprietary . Operating Systems Network Operating System (NOS) A network operating system (NOS ) is software that manages network resources and allows computers to communicate over a network . Windows Server , developed by Microsoft , is an example of a network operating system . Characteristics of a Network Operating System Allows for the centralised management of users , data and security across multiple devices on a network . Enables resources such as files , applications and printers to be shared over the network . Manages user authentication and permissions control . Oversees remote access and system monitoring tools . The main type of device that uses a NOS is a server . Other devices, such as desktops or laptops , connect to the server to access shared resources . Windows Server is an example of a popular NOS . Advantages of a Network Operating System Administrators can manage users , files and security on a network from one central location . Resources such as files , printer access and applications can be shared across the network . Access levels can be controlled and user authentication helps protect data . An NOS is scalable - more devices and users can be added as needed . Central servers managed by a NOS make it easier to back up and restore important files . Disadvantages of a Network Operating System Purchasing a NOS and maintaining the servers it runs on can be expensive . Setup and management is complex and may require skilled administrators . If the main server running the NOS fails , connected computers may lose access to resources . Heavy traffic or poor configuration could slow the network down . Who uses a Network Operating System? Application developers can use a NOS to build , test and manage apps that work across networks , such as web applications , multiplayer games or cloud tools . This type of operating system is also used by organisations that need to manage multiple devices , users and resources efficiently across a network , such as a small business or a school . Open Operating System An open operating system is open-source , meaning its source code is freely available for anyone to view , modify and distribute . Source code is the original set of instructions written by a programmer using a high-level language such as Python , Java or C++ . Characteristics of an Open Operating System Users have access to the source code and can see how the OS works . The source code can be modified to suit the specific needs of the user . Development and maintenance may be led by an online community . An open OS is usually free with no licensing costs for most versions. Linux is an example of an open operating system . Android is technically an open-source OS , but most commercial Android devices (like Google Pixel phones ) include proprietary components (like Google Docs or Gmail ), which makes the full system not completely open source . Advantages of an Open Operating System It is usually free to use , modify and distribute the source code . Because the source code can be seen and modified , this type of OS is flexible and customisable . There may be updates from an online community maintaining and improving the software . Promotes experimentation to learn how systems work and try new ideas . Disadvantages of an Open Operating System Programming knowledge and skills are required to modify the source code . There may be security risks if someone edits the source code and redistributes it with malicious code . There will be less official support compared to a proprietary operating system . Some proprietary applications (like Microsoft Access for databases) will only work on a proprietary OS (like Windows ). Who uses an Open Operating System? App developers would use an open OS when the device their application will be used on is not tied to a specific proprietary system (like Windows or MacOS ). For example, a charity making a free educational app for developing countries would choose an open OS so it can run on low-cost , older smartphones . It can be customised and tested on a range of devices . Applications for specific single-purpose systems would also use an open OS , such as an information terminal in a museum . Linux could be used to develop a simple user interface and remove unnecessary features . Proprietary Operating System A proprietary operating system is software that is owned by a company or individual and the source code is not accessible for users to view , modify or distribute . Users must typically buy a licence or agree to the terms of use . Characteristics of a Proprietary Operating System The source code is hidden from the user and cannot be legally modified . A paid licence or subscription is usually required to use the software . It may be maintained and updated by the developer(s) who own it . Only the developer controls updates and the features that are added or fixed . Examples include Microsoft Windows (e.g. Windows 11 ), macOS (for Apple desktops and MacBooks ), iOS (for iPhones ) and iPadOS for iPads ). Advantages of a Proprietary Operating System There is an expectation that it is user-friendly and has been well tested . There may be official support and regular updates for improvements and bug removal . A proprietary OS has a high compatibility with proprietary software such as Microsoft Office or Adobe editing apps . The OS is expected to be stable and secure , with access restricted to system files . Disadvantages of a Proprietary Operating System A paid licence to use the OS is often required , which may be expensive . There is limited customisation for users as the source code cannot be seen or modified . Users rely on the vendor (developer ) for updates and bug fixes . Some proprietary OS are designed to only work on specific hardware (such as iOS only working on iPhones ). Who uses a Proprietary Operating System? App developers will need to use a proprietary OS if they are developing applications for a device that requires a specific proprietary OS , for example if they are creating a game for iPhones , they will need to use iOS . A company designing a finance application on desktops with Microsoft Access and Microsoft Excel must use a proprietary OS like Windows so that it can be integrated with these other types of proprietary applications . Q uesto's Q uestions 1.2 - Operating Systems: 1. What is an operating system ? [2 ] 2. For each of the three types of operating systems , create a poster , information sheet or factfile which includes the following information : Characteristics Advantages Disadvantages Example of how it could be used [10 per OS ] Windows 11 is Microsoft's current operating system . Windows 1.0 was their first release, introduced in 1985 and included basic versions of Calculator , Notepad and Paint . D id Y ou K now? 1.1 - Programs & Applications Topic List 1.3.1 - Application Types

Learn about how to convert between the denary (decimal), binary and hexadecimal number systems. Based on the 2020 Eduqas (WJEC) GCSE specification. 4.1: Number Systems Exam Board: Eduqas Specification: 2020 What is binary? By now you should know that computer systems process data and communicate entirely in binary . Topic 1.4 explained different binary storage units such as bits (a single 0 or 1), nibbles (4 bits) and bytes (8 bits). Binary is a base 2 number system. This means that it only has 2 possible values - 0 or 1 . Because binary is a base 2 number system, binary numbers should be written out with a 2 after them, like this: 10101002 What is denary? Denary (also known as decimal ) is the number system that you've been using since primary school. Denary is a base 10 number system. This means that it has 10 possible values - 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 . Because denary is a base 10 number system, denary numbers should be written out with a 10 after them, like this: 165 10 How to convert from binary to denary: How to convert from denary to binary: What is hexadecimal? Hexadecimal is a base 16 number system. This means that it has 16 possible values - 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E and F . Because hexadecimal is a base 16 number system, hexadecimal numbers should be written out with a 16 after them, like this: 6E16 Hexadecimal is used as a shorthand for binary because it uses fewer characters to write the same value . This makes hexadecimal less prone to errors when reading or writing it , compared to binary. For example, 1001111010112 is 9EB16 . Hexadecimal only uses single-character values. Double-digit numbers are converted into letters - use the table on the right to help you understand. How to convert from binary to hexadecimal: How to convert from hexadecimal to binary: Converting from denary to hexadecimal / hexadecimal to denary To convert from denary to hexadecimal or the other way round you must convert to binary first . Denary > Binary > Hexadecimal Hexadecimal > Binary > Denary Use the videos on this page if you need help converting to or from binary. The most common number systems question in exams are from denary to hexadecimal or from hexadecimal to denary so make sure that you practice these conversions. Q uesto's Q uestions 4.1 - Number Systems: 1. Explain why hexadecimal numbers are used as an alternative to binary . Use an example . [ 3 ] 2. Convert the following values from binary to denary : a. 00101010 2 b. 11011011 2 c. 01011101 2 d. 11101110 2 e. 01011111 2 [1 each ] 3. Convert the following values from denary to binary : a. 35 10 b. 79 10 c. 101 10 d. 203 10 e. 250 10 [1 each ] 4. Convert the following values from binary to hexadecimal : a. 11110101 2 b. 01100111 2 c. 10111010 2 d. 10010000 2 e. 11101001 2 [1 each ] 5. Convert the following values from hexadecimal to binary : a. C2 16 b. 8A 16 c. DE 16 d. 54 16 e. F7 16 [1 each ] 6. Convert the following values from denary to hexadecimal : a. 134 10 b. 201 10 c. 57 10 d. 224 10 e. 101 10 [1 each ] 7. Convert the following values from hexadecimal to denary : a. 32 16 b. A5 16 c. 88 16 d. C0 16 e. BE 16 [1 each ] Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube Click the banners above to try self-marking quizzes (Google Form) on these topics. Denary to Binary: Binary to Denary: Binary to Hexadecimal: Hexadecimal to Binary: 3.9 Protection Against Threats Theory Topics 4.2 - Signed Binary

Learn about the devices used to host applications, including consoles, desktops, haptics, laptops, servers, smart devices, tablets / hybrid devices and wearables. 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 1.2 - Devices Watch on YouTube : Devices You need to know the characteristics of the eight types of devices shown below that application platforms run on . You must also understand the advantages and disadvantages of each device . YouTube video uploading soon What You Need to Know Devices Game consoles are designed specifically for playing video games , usually connected to a TV . Desktops are powerful and customisable personal computers designed for use at a desk . Haptic devices allow users to feel vibrations with touch . Game controllers and smartphones use haptics. Laptops are portable computers with a built-in screen and keyboard , suitable for work on the go . Servers are powerful computers on a network that process requests sent by other systems. Smart devices connect to a network allowing it to communicate with other devices and be controlled remotely . Tablets use a large touchscreen and are more portable than a laptop , ideal for browsing and media . A hybrid device is a laptop with a detachable screen . Wearable devices such as a smartwatch are worn on the body and often monitor the user's condition in real-time . Q uesto's Q uestions 1.2 - Devices: 1. What? [2 ] 2. What? [1 ] 3. What? [1 ] 4. What? [1 ] Check out the Shorts on the CSNewbs YouTube channel if you are interested in how video game consoles have evolved over time . There are separate videos for PlayStation , Xbox and Nintendo consoles. D id Y ou K now? 1.1 - Application Platforms Topic List 1.3 - Storage Locations

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 how to link to other websites by using the anchor tag. 4. Hyperlinks HTML Guide Watch on YouTube: A hyperlink is a link to another web page . In this section, you will link your page to a real website, like Wikipedia. Hyperlinks require the anchor tags and Copy a URL Firstly you need to copy the full web address of the web page that you would like to link your page to. Choose an appropriate web page that relates to your chosen topic. Create the Anchor Tag 4. Close the start of the tag . 1. Open the start of the tag . 2. Type href (stands for hypertext reference ). 3. Paste the URL inside speech marks . 5. Type the text you want the user to click on . 6. Time to close the tag . When you save your webpage and run it in a browser you will be able to click highlighted text to open the website you have chosen. Add at least three different hyperlinks to your webpage. Try to add the 2nd & 3rd links without looking at this page - practise makes perfect. Add a Hyperlink within a Sentence You can also create an anchor tag within a sentence. Hyperlinks are important to link webpages together. Next is time for adding pictures! Either change one of your previous hyperlinks to be in the middle of a sentence or create a new one. 3. Text Tags HTML Guide 5. Images

Learn how to easily remove objects in Greenfoot in only two lines of code. Part 4 of the Greenfoot Tutorial for the Eduqas / WJEC GCSE 2016 specification. 4. Remove Objects Greenfoot Tutorial 1. Removing Objects Watch on YouTube: Open the editor for your main character . Underneath the if statements for using the arrow keys is where we type the removal code . If you have chosen a different collectible object, type the exact name of that class instead of Orange (e.g. Apples or Ants). 2. Add Danger to your Game Use the same code as you did earlier but change the class (instead of Orange. class I have chosen Sheep. class ). Time to code your main character to be removed if they are touched by the enemy objects ! Open the editor for your enemy class . The removal code is placed beneath the code you have already written. Check out the extension page if you want the game to stop when the main character is removed. < Part 3 - Random Movement Part 5 - Play Sounds >

Explains the components of the CPU, the different registers, buses, how the FDE cycle works, CPU performance factors, pipelining, Von Neumann architecture and Harvard architecture. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 1.1 - Structure and Function of the Processor Specification: Computer Science H446 Watch on YouTube : CPU components Registers Buses The FDE cycle CPU performance Pipelining Von Neumann vs Harvard Contemporary architecture The Central Processing Unit ( CPU ) is the most important component in every computer system. The purpose of the CPU is to process data and instructions by constantly repeating the fetch-decode-execute cycle . In this cycle, instructions are fetched from RAM and transferred into the registers of the CPU to be decoded and executed . CPU Components The CPU has three key components : The control unit directs the flow of data and instructions inside the CPU and manages the FDE cycle , especially decoding instructions . The arithmetic logic unit ( ALU ) performs all arithmetic calculations and logical operations inside the CPU . Registers are small , ultra-fast storage locations that temporarily hold data , instructions or addresses during processing . The CPU also contains cache memory , which is temporary storage space for frequently accessed data . Registers A register is a small storage space for temporary data , instructions or addresses in the CPU . Each register has a specific role in the FDE cycle : The Program Counter ( PC ) stores the memory address of the next instruction to be fetched from RAM . The Memory Address Register ( MAR ) stores the memory address currently being accessed , which may be an instruction or data . The Memory Data Register ( MDR ) stores the data that is transferred from RAM to the CPU . The Current Instruction Register ( CIR ) stores the instruction that has been fetched from RAM . The Accumulator ( ACC ) stores data currently being processed and the result of calculations or logical operations made by the ALU . Buses Data and signals are transmitted between components across internal connections called buses . There are three types of computer bus : The data bus transmits data and instructions between the CPU , memory and other components such as input/output devices . It is bidirectional (data is sent both ways ). The address bus transmits the location in memory that the CPU is accessing . It is unidirectional (one-way ) from the CPU to RAM . The control bus transmits control signals (e.g. 'read ' or 'write ') from the CPU to coordinate other components . It is bidirectional . The FDE Cycle In the Fetch Decode Execute (FDE ) cycle , instructions are fetched from RAM , then decoded (understood) and executed (processed) in the CPU . This cycle is performed by the CPU millions of times every second using the registers and buses explained above. This cycle is how the CPU processes data and instructions for each program or service that requires its attention . CPU Performance The performance of the CPU is affected by three main factors : Clock speed is t he number of cycles per second , so a higher clock speed means more instructions can be executed per second . The number of cores is important as more cores allow a CPU to carry out multiple instructions simultaneously , improving multitasking and parallel processing . Cache memory is small and very fast memory inside the CPU that stores frequently used instructions , reducing the time needed to access RAM . Pipelining Pipelining is the concurrent processing of multiple instructions . An instruction can be fetched while another is decoded and another is executed . This overlapping of instructions increases the overall speed of program execution . Computer Architecture Computer architecture refers to the design and organisation of a system’s components and how they interact . There are two types of architecture to know: Von Neumann architecture uses a single main memory (RAM ) that stores both program instructions and data . This means instructions and data travel along the same buses , which can cause a bottleneck (congestion ). Harvard architecture separates the storage of program instructions and data into two different memory locations . This allows instructions and data to be fetched at the same time , improving performance . You also need to know about c ontemporary (modern) architecture , which includes features such as onboard ( integrated ) graphics , performance boosting mode , out-of-order execution and virtual cores . Q uesto's K ey T erms Components of the CPU: control unit (CU), arithmetic logic unit (ALU), registers, cache memory Registers: program counter (PC), memory address register (MAR), memory data register (MAR), current instruction register ( CIR), accumulator (ACC) Buses: data bus, address bus, control bus, unidirectional, bidirectional FDE Cycle: fetch stage, decode stage, execute stage CPU Performance: clock speed , number of cores , cache memory Pipelining: pipelining Computer architecture: Von Neumann, Harvard, contemporary D id Y ou K now? The Apollo Guidance Computer ( AGC ) for NASA's Apollo 11 mission , when humans first set foot on the moon , had a CPU clock speed of about 1 megahertz - slower than many GCSE-level calculators used today. A-Level Topics 1.2 - Types of Processor

Learn about the different protocols used to transfer data across a network, including TCP/IP, FTP, SMTP and Ethernet. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 2.7 - Protocols Exam Board: OCR Specification: 2016 - Unit 1 What is a protocol? A protocol is a set of rules that allow devices on a network to communicate with each other . Protocols to Transfer Data: TCP / IP / UDP TCP ( Transmission Control Protocol ) breaks data down into small packets to be transferred across a network and reorders them back into the original data at the destination . TCP checks for errors when sending data packets, which makes it slower than UDP for data transfer, but it guarantees that no packets have been lost on the way. IP ( Internet Protocol ) is in charge of routing and addressing data packets to ensure data is transferred across networks to the correct destination . It is also an addressing system - every device on a network is given a unique IP address . TCP and IP are often used together to transfer data across the internet. UDP ( User Data Protocol ) is a faster alternative to TCP for transferring data. It is used where low latency ('low lag') is important, such as online gaming and video chat . However, UDP does not automatically check for errors so packets are more likely to be lost or received out of order . HTTP is a protocol that can be used to transfer web pages on the world wide web so that users can view them in a web browser . All URLs start with either HTTP or HTTPS (e.g. https://www.csnewbs.com ). HTTPS is a more secure version of HTTP that works with another protocol called SSL (Secure Sockets Layer ) to transfer encrypted data . You should see a padlock symbol in the URL bar if your connection to that website is secure. HTTP/HTTPS (Hyper Text Transfer Protocol) FTP (File Transfer Protocol) FTP ( File Transfer Protocol ) is used to transfer files across a network. It is used most often to upload or download files to/from a file server . ICMP ( Internet Control Message Protocol ) collects network status information (such as router errors) and is used for troubleshooting . SNMP ( Simple Network Management Protocol ) is a protocol that records network statistics , such as router usage . Network Management Protocols Email Protocols SMTP ( Simple Mail Transfer Protocol ) is a protocol used to send emails to a mail server and between mail servers . POP ( Post Office Protocol ) is for downloading and storing emails from a mail server. TCP/IP Protocol Stack The TCP/IP protocol stack is a model split into 4 layers . The model is used to visualise the different parts of a network as each of the four layers has a specific role . Splitting a network design into layers is beneficial to programmers as it simplifies design , making it easier to modify and use . Each layer has a certain purpose and is associated with different protocols . 4 Allows humans and software applications to use the network e.g. browsers (HTTP /HTTPS ), email (SMTP / POP ), file transfer (FTP ) and network management (SNMP ) applications. 3 TCP breaks the data down into data packets . This layer makes sure the data is sent and received in the correct order and reordered at the destination without errors. UDP can also be used for faster , but less reliable , data transfer . 2 The network layer is also known as the ' Internet Layer '. IP is responsible for addressing and routing data packets . The optimal route for the data to take is calculated in this layer. ICMP may be used here for network monitoring . 1 This layer handles transmission errors and passes data to the physical hardware such as routers . It also sets out the final format of data packets . Q uesto's Q uestions 2.7 - Protocols: 1. Describe each of the following protocols . Also, state the protocol's full name and draw an icon or diagram for each: a. TCP b. IP c. UDP d. HTTP & HTTPS e. FTP f. ICMP g. SNMP h. SMTP i. POP [1 each ] 2. State which protocol would be used in the following scenarios: a. Transferring a music file to a friend over the internet. b. Sending an email to a friend in Japan. c. Checking for errors on a network. d. Having a video call with a colleague in London. e. Receiving an email from the bank. f. Watching a video on YouTube. g. Checking the statistics of usage on a network [1 each ] 3. Summarise each layer of the TCP/IP stack and identify the protocols used in each layer . [ 8 ] 2.6 - Software Troubleshooting Topic List 3.1 - Server Types

Learn about the three factors that affect computer performance - cache memory, clock speed and the number of cores. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 1.2: CPU Performance Exam Board: OCR Specification: J277 Watch on YouTube : Clock Speed Cache Memory Number of Cores The performance of a computer system is affected by three main factors: Cache Memory What is cache memory? Cache memory is temporary storage for frequently accessed data . How does cache memory improve performance? Cache memory is closer to the CPU than RAM , meaning that it can provide data and instructions to the CPU at a faster rate . A computer with more cache memory (e.g. 8GB instead of 4GB) should have a higher performance because repeatedly used instructions can be stored and accessed faster . What is the limitation of cache memory? Cache memory is costly, so most computers only have a small amount . Clock Speed What is clock speed? Clock speed is the measure of how quickly a CPU can process instructions . Clock speed is measured in Gigahertz (GHz) . A typical desktop computer might have a clock speed of 3.5 GHz . This means it can perform 3.5 billion cycles a second . How does clock speed improve performance? The faster the clock speed, the faster the computer can perform the FDE cycle resulting in better performance because more instructions can be processed each second . How does overclocking and underclocking affect performance? Default clock speed: 3.5 GHz Underclocking Overclocking 3.9 GHz 3.1 GHz Overclocking is when the computer's clock speed is increased higher than the recommended rate. This will make the computer perform faster, but it can lead to overheating and could damage the machine . Underclocking is when the computer's clock speed is decreased lower than the recommended rate. This will make the computer perform slower but will increase the lifespan of the machine . Number of Cores What is a core? A core is a complete set of CPU components (control unit, ALU and registers). Each core is able to perform its own FDE cycle . A multi-core CPU has more than one set of components within the same CPU. How does the number of cores improve performance? In theory, a single-core processor can execute one instruction at a time , a dual-core processor can execute two instructions, and a quad-core can execute four instructions simultaneously . Therefore, a computer with more cores will have a higher performance because it can process more instructions at once . What are the limitations of having more cores? If one core is waiting for another core to finish processing, performance may not increase at all. Some software is not written to make use of multiple cores , so it will not run any quicker on a multi-core computer. Q uesto's Q uestions 1.2 - CPU Performance: Cache Size & Levels 1a. What is cache memory ? [ 2 ] 1b. Describe two ways that more c ache memory will mean performance is higher . [ 4 ] 1c. Explain why most computers only have a small amount of cache memory. [ 1 ] Clock Speed 2a. What is clock speed ? What is it measured in? [ 2 ] 2b. Explain how a higher clock speed improves performance . [ 2 ] 2c. Explain the terms 'overclocking ' and 'underclocking ' and explain the effects of both on the performance of a computer. [ 4 ] Number of Cores 3a. What is a core ? [ 2 ] 3b. Explain why a quad-core processor should have a higher performance than a dual-core processor . [ 3 ] 3c. Explain two reasons why having more cores doesn't necessarily mean the performance will be better . [ 2 ] 1.1b - Registers & FE Cycle 1.3 - Embedded Systems Theory Topics