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Learn about project planning tools such as the Arrow diagram, Critical Path Analysis (CPA)/Critical Path Method (CPM), Flowcharts, Gantt charts, PERT charts and SWOT (Strengths / Weaknesses / Opportunities / Threats) analysis. 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) 3.2 - Project Planning Tools Watch on YouTube : Project planning tools Arrow diagram Critical path analysis Flowcharts Gantt charts PERT charts SWOT analysis Project Planning Tools Project planning tools help to visualise the project by clearly showing tasks , timelines and dependencies . They also break down complex work into smaller , manageable steps and can be used to track progress and identify delays . Each tool suits different project needs and has its own advantages and disadvantages . Choosing the right tool makes planning more accurate , efficient and successful . Arrow Diagram The arrow diagram method is a project planning tool that represents tasks as arrows connected in sequence to show their order and dependencies . It helps identify the critical path . This is the longest sequence of dependent tasks that determines the project’s minimum completion time . This method is useful for visualising task relationships , spotting bottlenecks and showing the order of activities . Critical Path Analysis Critical path analysis ( CPA ), also known as the critical path method ( CPM ), is a project planning tool used to identify the critical path . This is the sequence of tasks that determines the shortest possible project duration . It highlights tasks that cannot be delayed without affecting the overall timeline . Critical path analysis helps prioritise resources , manage dependencies and minimise project delays . Flowcharts A flowchart is a diagram that represents a process or workflow using standard symbols and arrows to show the sequence of steps . It helps visualise decision points and actions and clearly highlights the flow of information or tasks . Flowcharts make complex processes easier to understand , communicate ideas to clients and troubleshoot potential problems . Gantt Charts A Gantt chart is a visual project management tool that displays tasks along a timeline , showing their start and end dates . It helps track task dependencies , overlaps and progress at a glance . Gantt charts are useful for coordinating work , meeting deadlines and ensuring all project stages are completed in order . PERT Charts A PERT ( program evaluation and review technique ) chart is a project planning tool that maps tasks , their dependencies and timelines in a network diagram . It uses three time estimates ( optimistic , most likely and pessimistic ) to calculate expected completion times for each task . PERT charts are especially useful for scheduling complex projects and identifying the critical path to meet deadlines . SWOT Analysis SWOT analysis is a strategic planning tool used to identify a project’s strengths , weaknesses , opportunities and threats . Strengths and weaknesses focus on internal factors ( controllable by the organisation ), while opportunities and threats look at external influences ( outside of the organisation's control ). It helps guide decision-making by highlighting advantages , weaknesses to address and potential risks or openings in the wider environment . Q uesto's Q uestions 3.2 - Project Planning Tools: 1. Define the term 'critical path ' and explain why it is calculated . [3 ] 2. Explain the S , W , O and T in SWOT analysis (not just what they stand for). [4 ] 3. Choose three project planning tools and describe the advantages and disadvantages of each . [ 12 ] Henry Gantt , an American engineer , created the Gantt chart in the 1910s . It has been used as a planning tool in many major projects , including building the Hoover Dam . D id Y ou K now? 3.1 - Planning Projects Topic List 4.1 - Gathering Client Requirements

Learn about the importance of testing applications, test plan structure, test types and test data. Resources based on Unit F161 (Developing Application Software) for the OCR Cambridge Advanced Nationals in Computing (H029 / H129) AAQ (Alternative Academic Qualification). Qualification: Cambridge Advanced Nationals in Computing (AAQ) Certificate: Computing: Application Development (H029 / H129) Unit: F161: Developing Application Software 5.1 - Testing Watch on YouTube : Purpose of testing Test plan structure Test data Types of testing You need to know the purpose , importance , advantages and disadvantages of testing applications , as well as the impacts of not carrying out testing . You must understand the structure and contents of test plans and the importance of testing , remedial actions and retesting during application development. You need to know the role of each type of test data (normal , extreme and erroneous ). Finally, the purpose , advantages and disadvantages of each type of testing (technical and user ) must be known as well as when and how each type should take place . What You Need to Know Purpose of Testing ? YouTube video uploading soon Test Plan Structure ? YouTube video uploading soon Types of Test Data ? YouTube video uploading soon Types of Testing ? YouTube video uploading soon Q uesto's Q uestions 5.1 - Testing: 1. What? [2 ] 2. What? [1 ] 3. What? [1 ] 4. What? [1 ] ? D id Y ou K now? 4.1 - Security Considerations Topic List 5.2 - Application Installation

Learn about the purpose of Green IT, the benefits for an organisation following its practice and methods of use. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 4.3 - Green IT Exam Board: OCR Specification: 2016 - Unit 2 What is 'Green IT'? ‘Green IT ’ is to use computers and IT resources in an efficient and environmentally responsible way to reduce an organisation’s carbon footprint . To 'reduce carbon footprint ' means to decrease the amount of pollution (such as CO2 ) produced by an organisation and to engage in more eco-friendly practice. Examples of Green IT Practice Global Requirements of Green IT United Nations Climate Change conferences occur every year and are attended by leaders of each country in the United Nations. The conferences establish obligations for countries to work towards reducing their carbon footprints and emissions of greenhouse gases . Whilst Green IT is not specifically mentioned in these talks, IT is a hugely important sector with large annual emissions that need to be reduced to meet the climate change limitations, such as the Paris Agreement. In the UK, the Greening Government ICT Strategy (running between 2011 and 2015) was an annual report that investigated how IT use could become 'greener' within the government . Positive consequences of this strategy included: Using more cloud storage technology , enabling fewer individual storage devices to be purchased, reducing emissions . Using social media more widely to contact voters - saving money by posting fewer letters and leaflets. Increasing the use of teleconferencing and video calls - reducing the need for unnecessary travel to meetings and avoiding the generation of heavy pollution. Q uesto's Q uestions 4.3 - Green IT: 1. What is meant by the term 'Green IT '. [3 ] 2a. Explain four ways that an organisation can follow good green IT practice . [4 ] 2b. Describe two reasons why it is beneficial to a company of following Green IT . [4 ] 3a. Why are the United Nations Climate Change conferences important ? [2 ] 3b. Describe two ways that the UK government have used Green IT . [4 ] Turn off computers , monitors and other connected devices when not in use . Adjust power options to help minimise power consumption. Use cloud storage or virtualisation to reduce the number of physical devices being bought, powered and maintained. Repair older devices rather than throwing them away. Consider if it is necessary to print a document before doing so and print only what is required . Recycle ink cartridges and paper . Donate older equipment to charities or schools for reuse . Why use Green IT? It is in an organisation's best interests to use Green IT practices for the following reasons: To become more sustainable by reducing the company's carbon footprint and positively impacting the environment . Reducing energy costs (e.g. by turning equipment off when not in use) and saving money . Improving the public image of the organisation as people are increasingly environmentally conscious and will prefer to do business with a company that follows environmentally-friendly policies. 4.2 - Global Legislation Topic List 5.1 - Data Types & Sources

Learn about the advantages and disadvantages of different types of software including open-source, closed-source, off-the-shelf and bespoke. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 2.1: Software Types Exam Board: OCR Specification: 2016 - Unit 1 Software refers to the programs and applications that run on a computer system. Open Source Software Source code is the software code written by programmers . If the software is open source it means that users can view and modify the code . Linux, Python and Firefox are examples of open source software. Benefits Drawbacks Because the source code is available to edit , it can be customised to the organisation's needs . Often shared in the public domain so users can work together to modify, debug and improve a product. Unwanted features can be removed to make the software run faster . There are security risks - some editors may add malicious code to the program. Open source software is often low in price and sometimes free. It may be difficult to receive support as development is often distributed between people in different locations. The code may be prone to errors as it may not have been tested fully. It requires technical skills to be able to adapt source code efficiently and to maintain the code . Closed Source Software If the software is closed source it means the code is restricted for users to view or modify . You buy the right to use the software but you don't actually own it. Microsoft Office, Fortnite and Spotify are examples of closed source software. Closed source software is also known as proprietary software because it is another company's property and protected by law. Benefits Drawbacks The code is well tested and has been professionally developed. Updates will generally be secure . Users must rely on the company to provide updates and fix issues. This might be infrequent or stop completely. The company can be held to account if it does not perform as listed in the terms and conditions upon purchase. Often not free (see Freeware below for free closed source software). Most developers will provide some form of help/support . Users cannot modify, debug or improve the code for their own benefit. Off-the-Shelf Software This is any software made for general use , with features that can be used in different ways and for different purposes . Examples include office software (e.g. Microsoft Office), video games (e.g. Minecraft) and image editors (e.g. Adobe PhotoShop). Back before internet downloads, people had to actually go to shops and buy software off the shelf and install it at home, hence the name. Benefits Drawbacks Should have been tested thoroughly so users can be confident that features will work as expected . Secure updates will be regular. It can be expensive to purchase some software , especially for a single user rather than a business. Some software, such as anti-virus protection, requires yearly licenses . It can be cheaper to purchase than bespoke software as it is not customised for a specific user or organisation. The software may contain additional features that the user / organisation doesn’t need which can reduce the performance of the system. The end users might be familiar with the software and trust the company (e.g. Microsoft Word). Bespoke Software This is any software that has been custom made for a specific organisation or user. For example, programmers might be hired by a company to create software for a specific task. Hospitals and schools use bespoke software to track and manage patients / students. It can be expensive to commission bespoke software as programmers and user interface designers need to be hired and there could be issues with rights to any created software. Benefits Drawbacks The software is built to the company's requirements , it is unique to their needs. Unwanted features can be removed to make the software run faster . Bespoke software is expensive to develop because it is tailor-made for the company. Staff may require training on using the system because it is unique . The look of the software (e.g. design & layout ) can be customised to fit the company's image. Because it has been custom-made, the original programmers may be needed to maintain the software and fix errors . Shareware This software allows the user to trial the program for a limited time before forcing them to buy the product or stop using it. For example, WinRAR is utility software that asks the user to buy the full version after 40 days. This allows the user to get a taste of what the software offers before choosing whether to buy it fully or not . Freeware This is software that is freely available to download and use . These are usually closed-source software that earn money through adverts or additional purchases. Rights to the software remain with the author despite the free access. App developers may release their app as freeware to allow users to try the software and then encourage them to purchase a full version with more features. Unlike shareware, the user should be able to keep using the product for free indefinitely, though their version may have features restricted or adverts enabled. Examples of freeware software include iTunes , Clash of Clans and Adobe Acrobat Reader (for PDFs). Embedded Software An embedded system is when a smaller computer system is installed within a larger device , such as a washing machine, traffic light or car. Embedded systems have a dedicated purpose and often run in real-time . Because of the small size, the embedded software will usually have memory and storage restrictions . Q uesto's Q uestions 2.1 - Software Types: 1. Describe the 7 types of software , listing the advantages and disadvantages of each. a. Open Source b. Closed Source c. Off-the-Shelf d. Bespoke e. Shareware f. Freeware g. Embedded [6 each ] 1.8 & 1.9 - Number Systems Topic List 2.2 - Applications Software

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 different types of hardware that allow data to be sent between systems, including router, modem, bridge and WAP. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.5: Communication Hardware Exam Board: OCR Specification: 2016 - Unit 1 The devices on this page are used to create or link together networks , allowing data to be sent between computer systems . Hub A hub receives data packets from a connected device and transfers a copy to all connected nodes . Switch A switch receives data packets , processes them and transfers them on to the device s pecifically listed in the destination address of the packet. Modem Modems are used to send data across the telephone network . The telephone lines can only transfer analog signals so a modem is used to convert a computer's digital data into an analog signal . Another modem converts the signal back to a digital format at the receiving end. Router Routers are used to transfer data packets between networks . Data is sent from network to network on the internet towards the destination address listed in the data packet. A router stores the address of each computer on the network and uses routing tables to calculate the quickest and shortest path . Wireless Access Point (WAP) Provides a link between wireless and wired networks . It creates a wireless local area network that allows WiFi enabled devices to connect to a wired network. Combined Device Also known as a hybrid device , this provides the functionality of multiple communication devices (e.g modem, router, switch and/or wireless access point) in a single device . They can be more expensive than a single device but are more adaptable - if the routing part of the device fails it might still be able to function as a switch / wireless access point etc. However, you will see an increased performance from a standalone device rather than a combined one as standalone devices have more complex features (e.g. VPN support). Network Interface Card (Network Adapter) A Network Interface Card (often shorted to NIC ) is an internal piece of hardware that is required for the computer to connect to a network . It used to be a separate expansion card but now it is commonly built directly into the motherboard (and known as a network adapter ). Wireless network interface cards allow wireless network connection. Q uesto's Q uestions 1.5 - Communication Hardware: 1. What is the difference between a hub and a switch ? [2 ] 2. Explain how a modem works. [3 ] 3. Explain the purpose of a router . [2 ] 4. What is a Wireless Access Point (WAP )? [2 ] 5. Describe what is meant by a 'combined device '. Give one advantage and one disadvantage of using a combined device. [3 ] 1.4 - Connectivity 1.6 - Hardware Troubleshooting Topic List

Learn about digital methods of protecting data such as anti-malware, firewall, usernames and passwords, levels of access and encryption. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 5.5 - Digital Security Exam Board: OCR Specification: 2016 - Unit 1 ****** Usernames & Passwords Usernames must be matched with a secure password to minimise the chances of unauthorised users accessing a system. Passwords should contain a mix of uppercase and lowercase letters , punctuation and numbers . Passwords should be of a substantial length (at least 8 characters) and should be regularly changed . Digital Security Measures Firewall Firewalls (see 2.3 ) prevent unauthorised access to or from a network . Firewalls filter data packets and block anything that is identified as harmful to the computer system or network. Firewalls can also be used to block access to specific websites and programs. Encryption Encryption is the conversion of data ( plaintext ) into an unreadable format ( ciphertext ) so it cannot be understood if intercepted . Encrypted data can only be understood by an authorised system with a decryption key . Anti-Malware Anti-virus software (see 2.3 ) scans a system and removes viruses . If left to infect a system a virus could delete data or permit access to unauthorised users . Anti-spyware software removes spyware on an infected system so hackers cannot view personal data or monitor users. Organisations should install and regularly update anti-virus and anti-spyware programs. Permissions Permissions is the creation of different levels of file access so that only authorised people can access and change certain files . There are different levels of file access : No access Read-only Read/write Q uesto's Q uestions 5.5 - Digital Security: 1a. Describe why usernames and strong passwords are necessary. [2 ] 1b. State 3 rules for choosing a strong password . [3 ] 2. Describe the purpose of anti-virus and anti-spyware software. [4 ] 3. Describe the roles of a firewall . [4 ] 4. Explain what encryption is. [3 ] 5. What are permissions ? What are the 3 levels of access ? [5 ] 5.4 - Physical Security Topic List 5.6 - Data & System Disposal

Learn about the six parts of a data packet and how packet switching works. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.2: Data Packets & Switching Exam Board: Eduqas Specification: 2020 What is a data packet? When sending data across a network, files are broken down into smaller parts called data packets . Whole files are too large to transfer as one unit so data packets allow data to be transferred across a network quickly . Each packet of data is redirected by routers across networks until it arrives at its destination. Data packets may split up and use alternative routes to reach the destination address. When all the packets have arrived at the destination address the data is reassembled back into the original file. Contents of a Data Packet Data packets contain six distinct pieces of data which are used to redirect the packets towards the destination address. Packet Switching vs. Circuit Switching The key difference is that a circuit-switched network sends data along the same route . A packet-switched network sends data packets along different routes . Packet Switching With a packet-switched network the data is split into packets . The data packets are transmitted over a network and may take different routes to its destination. When all the packets have arrived the data is reassembled . The Internet is an example of a packet-switching network. Advantages of Packet Switching: Transmission is more secure as it is harder for a hacker to intercept complete data because it can take different routes . If a network device fails the data packets can take an alternative route . Data packets can be sent efficiently and individually across less busy routes . Disadvantages of Packet Switching: Reassembling the data takes longer because packets may arrive out of order . It is less reliable than circuit switching as some data packets may not reach the destination (this is called packet loss ). Circuit Switching When data is transmitted over a circuit-switched network all of the data takes the same route to the destination address in one continuous stream . The data is quickly reassembled at the destination because it is already in the correct order . The old telephone system is an example of a circuit-switched network. Advantages of Circuit Switching: Reassembling the data is quick because the packets arrive in the order that they were sent. It is more reliable than packet-switching because data is sent in one continuous stream . The transmission is fast and should encounter fewer errors - once the connection has been securely established . Disadvantages of Circuit Switching: Less secure as hackers could intercept the data and more easily access the data as it all takes the same route. Establishing a connection takes time to set up. If any device fails on the route then the whole connection breaks and data transfer will be incomplete. Q uesto's Q uestions 3.2 - Data Packets & Switching: 1. Draw the data packet diagram and label all 6 pieces of information . [ 6 ] 2a. Describe how packet switching works . [3 ] 2b. Describe the advantages of packet switching . [3 ] 2c. Describe the disadvantages of packet switching . [2 ] 3a. Describe how circuit switching works . [3 ] 3b. Describe the advantages of circuit switching . [3 ] 3c. Describe the disadvantages of circuit switching . [3 ] 3.1 - Network Characteristics Theory Topics 3.3 - Network Topology

Learn about six network devices - hub, switch, router, bridge, WAP and NIC. Also, learn about routing tables and cost diagrams. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.4: Network Hardware & Routing Exam Board: Eduqas Specification: 2020 Network Devices Hub A hub receives data packets from a connected device and transfers a copy to all connected nodes . Switch A switch receives data packets , processes them and transfers them on to the device specifically listed in the destination address of the packet. Router Routers are used to transfer data packets between networks . Data is sent from network to network on the internet towards the destination address listed in the data packet. A router stores the address of each computer on the network and uses routing tables to calculate the quickest and shortest path . Bridge A bridge joins together two networks that use the same base protocols . For example, a bridge could link together a LAN to another LAN . Wireless Access Point (WAP) Provides a link between wireless and wired networks . It creates a wireless local area network that allows WiFi enabled devices to connect to a wired network. Network Interface Card (NIC) A Network Interface Card (often shortened to NIC ) is an internal piece of hardware that is required for the computer to connect to a network . It used to be a separate expansion card but now it is commonly built directly into the motherboard (and sometimes known as a network adapter ). Wireless network interface cards ( WNIC ) permit a wireless network connection. Routing A routing table is a list of the optimal routes for data packets to be sent from one device to another. Routing tables should be kept accurate and up to date to ensure that packets are transferred as quickly as possible . During routing the lowest cost route is calculated . This is the shortest path with the fastest nodes to transfer data. Below is a simplified network and basic routing table showing the lowest cost (optimal) route using node A as the source address. Q uesto's Q uestions 3.4 - Network Hardware & Routing: 1a. Describe the difference between a hub and a switch . [ 2 ] 1b. Explain how a modem works. [ 2 ] 1c. Describe the purpose of a router . [ 2 ] 1d. Describe the difference between a gateway and a bridge . [ 2 ] 1e. State what WAP stands for and describe its purpose . [ 2 ] 1f. State what NIC stands for and why it is required . [ 2 ] 2a. Describe what a routing table is and why they should be maintained . [ 2 ] 2b. In terms of routing, what does a low-cost route mean? [ 2 ] 2c. Copy and complete the routing table below using node J as the source address . [ 4 ] 3.3 - Network Topology Theory Topics 3.5 - Protocols

Learn about network topologies including client-server, peer-to-peer, bus, mesh and star. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 3.3 - Network Characteristics Exam Board: OCR Specification: 2016 - Unit 1 Network Topologies Network topology refers to the arrangement of computer systems on a network . Devices in a network topology diagram are often called ' nodes ' . Client-Server Network Clients make requests to a server , the server manages that request and responds . For example, if the user (client) makes a request to access www.csnewbs.com to a web server . Large services like Amazon and Google will need very powerful servers to handle millions of requests a second. The client is completely dependent on the server to provide and manage the information. The server controls network security , backups and can be upgraded to manage higher demand. Disadvantages: Large amounts of traffic congestion will cause the network to slow down . If a fault occurs with the server then the whole network will fail . IT technicians may be required to manage and maintain the network . Malware , such as viruses, can spread quickly across the network. Peer-to-Peer Network For peer-to-peer networks , data is shared directly between systems without requiring a central server . Each computer is equally responsible for providing data. Peer-to-peer is optimal for sharing files that can then be downloaded. Bus Topology The nodes are connected to a bus (a central cable which transfers all data on the network). How it works: The bus transfers data packets along the cable . As the data packets arrive at each computer system, the computer checks the destination address contained in the packet to see if it matches its own address . If the address does not match , the computer system passes the data packet to the next system . If the address of the computer system matches the destination address in the data packet, it is accepted and processed. At both ends of the cable are terminators to mark the end of the bus. Advantages: Because of the simple layout, it is easy to attach another system to the main cable without disrupting the whole network . A bus topology is quick to set up once the main cable has been established making it optimal for temporary networks . A bus topology is cost-effective because it usually contains less cabling than other topologies and requires no additional hardware (like a hub or switch). Disadvantages: Poor security as data packets are passed on to each system on the network. Data collisions are likely - this is when two systems attempt to transfer data on the same line at the exact same time. Resending the data wastes time and slows down the network . The main cable will only have a limited length which can become crowded and slows network speed as more systems are attached. The main cable must also be terminated properly . Token Ring Topology In a token ring network , computer systems are connected in a ring or a loop. How it works: A token (small data packet) is sent around the ring in one direction, being passed from one computer system to the next. A computer seizes the token and includes its own data when it transfers data. As the token arrives at each computer system, the system checks the destination address contained in the packet to see if it matches its own. If the addresses match, the computer processes the data otherwise it ignores it. Advantages: Data collisions are avoided as data packets are transmitted in one direction around the ring. Attaching more systems to a ring topology won't affect the transfer speed as much as other layouts like a bus topology because the data is transferred at a consistent speed . Disadvantages: If any system on the network fails then the whole network fails as the loop is broken and data can't be transferred to all systems. To add a new system to a ring topology the network must be temporarily shut down . Star Topology In a star network , each computer system is connected to a central node: a hub or switch . How it works: Each node is connected to the central node (usually a hub or switch ) and transfers its data packets here. The hub/switch looks at the destination address and transfers the packets to the intended computer only. Advantages: A star topology has improved security because data packets are sent directly to and from the hub / switch in the centre and not necessarily all devices like in a bus or ring topology. New systems can be attached directly to the central system so the network doesn't need to be shut down . System failures of attached computers won't usually cause complete network failure. Transfer speeds are generally fast in a star topology as there are minimal network collisions . Disadvantages: Extra hardware (the hub or switch) is required to be purchased, installed and maintained. If the central system (the hub or switch) fails then the whole network will be unusable until the error is fixed. Mesh Topology In a mesh network, each computer system is connected to every other computer system . How it works: Data packets are transferred to the destination address along the quickest path, travelling from node to node. If a pathway is broken, there are many alternative paths that the packets can take. Advantages: If one cable or system fails then data packets can take an alternative route and still reach the destination address. Because of the large possible number of systems and connections, a mesh topology can usually withstand large amounts of data traffic . New systems can be added to the network without disrupting the entire topology . Disadvantages: Because of the possibly large amount of cables required (especially in a complete mesh topology) this network layout can be expensive to install and maintain . Redundant cabling should be avoided - this is when cables are connected between systems that won't ever need to communicate . Configuration Before a computer system can use a network, three pieces of information must be configured (set up) correctly. IP Address An IP address is used to uniquely identify computer systems on a network , allowing communication between them. An example of an IP address is 195.10.213.120. Default Gateway When data is to be sent from one network to another , it must be sent through a default gateway . This default gateway is usually a router that connects the local network to another network . On many home networks , the default gateway will use the same private IP address : 192.168.1.1 Network managers can use automatic configuration which is quicker and easier to set up . A new device can connect to and use a network automatically , such as free WiFi in an airport. Network managers can also set manual configuration which improves security as new devices can’t be used until the addresses have been configured by a technician . This stops unauthorised devices from connecting to the network. Subnet Mask Subnetting is the act of dividing a physical network into smaller 'sub' networks (known as subnets ) . This helps to reduce traffic and means that users can externally access parts of a network (e.g. emails from home) without having to open the entire network. A subnet mask is used to define these subnets . The mask is used to determine the start and end address of each IP address in a subnet. A common subnet mask is 255.255.255.0 as making the first 3 sections full restricts the fourth section to 256 unique values. For example 113.12.14.230 and 113.12.14.157 are in the same subnet but 114.12.14.127 wouldn't be. Q uesto's Q uestions 3.3 - Network Characteristics: 1 a. Describe how peer-to-peer networks and client-server networks function. 1b. Give one use for both types of network. 2a. Draw and label a diagram for all 6 network topologies . 2b. Describe 2 advantages and 2 disadvantages of each network topology . 3 . What is an IP address ? Why is it necessary for networks? 4. Describe what is meant by a default gateway . 5a. What is subnetting ? 5b. What is the purpose of a subnet mask ? 5c. State a common subnet mask . How many unique devices can be used on a network with this subnet mask? 6. Describe 1 reason why a network manager may use automatic configuration and 1 reason why they may use manual configuration . Advantages: The network can be controlled centrally from the server to easily backup data and update software . Hardware, software and resources can be shared across the network, such as printers, applications and data files . The network allows for improved scalability , meaning more clients can be easily added to the central server . Disadvantages: Without a dedicated server there is no central device to manage security or backups . Backups must be performed on each individual system. Computer performance will decrease with more devices connected to the network, especially if other machines are slow. Advantages: This is a simpler network than client-server to set up as no server is required . Clients are not dependent on a server . Perfect for quickly sharing files between systems , such as downloading media files. 3.2 - Virtualisation Topic List 3.4 - Connection Methods

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 3.1f - Standard Algorithms Watch on YouTube : Bubble sort Merge sort Insertion sort Quick sort Linear search Binary search Djisktra's algorithm A* algorithm The OCR A-Level course requires an understanding of algorithms used for sorting , searching and pathfinding including how they can be used for traversing and how to write them in pseudocode or a high-level programming langauge . Bubble Sort Bubble sort repeatedly compares adjacent items and swaps them if they are in the wrong order . Its advantage is that it is very simple to understand and easy to implement . However, it is extremely slow for large lists , with a worst- and average-case time complexity of O(n²) . It performs slightly better (O(n)) if the list is already nearly sorted and the algorithm is optimised t o detect no swaps . Overall, it is easy but inefficient . YouTube video uploading soon Merge Sort Merge sort is a divide-and-conquer algorithm that repeatedly splits a list into smaller sublists , sorts them recursively and then merges them back together . Its major benefit is that it is consistently fast with a time complexity of O(n log n) in the best , average and worst cases , making it very efficient for large datasets . It is also stable and works well with linked lists . However, a drawback is that it requires additional memory to store the temporary sublists , making its space complexity O(n) . Merge sort is therefore reliable but not memory-efficient . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Insertion Sort Insertion sort works by taking each item and inserting it into the correct position in a growing sorted portion of the list . It is efficient for small or nearly sorted datasets and has a best-case complexity of O(n) , making it useful in real-time systems or hybrid algorithms . However, for large , randomly ordered datasets it becomes slow , with average- and worst-case performance of O(n²) . It uses very little memory space - (O(1) - which is one of its key benefits compared to more complex sorts like merge or quick . YouTube video uploading soon Quick Sort Quick sort is a divide-and-conquer algorithm that chooses a pivot , partitions the list into smaller elements and larger elements , and recursively sorts the partitions . Its main advantage is speed : the average-case time complexity is O(n log n) and it is often faster in practice than merge sort due to good cache performance and in-place partitioning . However, if poor pivot choices are made (e.g., always picking the first item in an already sorted list ), the worst case becomes O(n²) . Despite this, quick sort is widely used because good pivot-selection strategies minimise this risk . YouTube video uploading soon Linear Search Linear search checks each item in a list one by one until it finds the target value or reaches the end . Its benefit is that it works on any list (sorted or unsorted ) and is extremely simple to use and implement . The drawback is inefficiency for large datasets because its best , average and worst time complexity is O(n) . This means the time taken grows directly with the size of the list , making it suitable only for small collections of data . YouTube video uploading soon Binary Search Binary search repeatedly halves a sorted list to locate a target value , making it much faster than linear search . Its key benefit is efficiency : the time complexity is O(log n) for best , average and worst cases , meaning performance scales extremely well with large datasets . However, its major limitation is that the data must be sorted beforehand , and maintaining a sorted list can itself be costly . When this condition is met , binary search is one of the most efficient searching algorithms available. YouTube video uploading soon Dijkstra's Algorithm Dijkstra’s algorithm is a pathfinding algorithm used to find the shortest path from a starting node to all other nodes in a weighted graph with non-negative edge weights . It works by gradually exploring the graph , always choosing the next closest unvisited node , updating the shortest known distances to its neighbours and marking nodes as 'visited ' once the shortest path to them is confirmed . The algorithm continues until all nodes have been processed or the destination is reached , guaranteeing the shortest path . YouTube video uploading soon A* Algorithm The A* algorithm is an informed pathfinding algorithm that also finds the shortest path in a weighted graph , but it uses a heuristic (an estimate of the distance to the goal ) to guide its search more efficiently toward the target . A* combines the actual cost from the start to a node with a heuristic estimate of the remaining distance , allowing it to prioritise exploring nodes that appear more promising . YouTube video uploading soon Q uesto's K ey T erms Sorting Algorithms: bubble sort, flag, pass, merge sort, insertion sort, quick sort, pivot Seraching Algorithms: linear search, binary search, precondition Pathfinding Algorithms: Dijsktra's algorithm, A* algorithm, heuristic D id Y ou K now? Halo: Combat Evolved released on the Xbox in 2001 and introduced groundbreakingly convincing enemy AI for the time. Pathfinding algorithms were used more realistically than older games so that enemies wouldn't just run directly at the player but behaved in different ways depending on the situation , such as cooperating , flanking or retreating by reacting dynamically to the player . 3.1e - Data Structure Algorithms A-Level Topics

Learn about the methods of gathering client requirements such as document analysis, focus groups, interviews, meetings, observation, problem reports, questionnaires, shadowing and suggestion analysis. Based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced National in Computing (H029 / H129) (AAQ - Alternative Academic Qualification). Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F160: Fundamentals of Application Development Certificate: Computing: Application Development (H029 / H129) 4.1 - Methods of Gathering Client Requirements Watch on YouTube : Gathering Client Requirements For each of the nine methods of gathering client requirements , you need to know : Its purpose and when it would be used . The type of information and data that can be collected using it. The advantages and disadvantages of using it. How client requirements determine if it would be used. Gathering Client Requirements Methods of Gathering Client Requirements T here are nine methods of gathering client requirements you need to know : Reviewing existing documents (e.g. manuals and reports ) to understand the current system and requirements . Gathering a small group of users or stakeholders to discuss needs , expectations and ideas . Asking stakeholders structured or open-ended questions to collect detailed requirements . Bringing together clients and developers to share information , clarify requirements , and make decisions . Watching users perform tasks to see how they interact with the current system . Using logged issues or complaints from an existing system to identify new requirements . Distributing structured forms with questions to gather requirements from a wide group quickly . Following a user during their normal tasks to gain deeper insights into workflows and needs . Reviewing client or user-submitted ideas and feedback to shape requirements . Q uesto's Q uestions 4.1 - Methods of Gathering Client Requirements: 1. Explain what document analysis , problem reports , shadowing and suggestion analysis are. [8 ] 2. Give two advantages and two disadvantages of two other methods not mentioned in Q1 . [8 ] 3. The video game company that makes the ' Age of the Dragon ' series faced a letdown in their previous release , ' The Guard of the Veil '. They need to ensure that their next game sells a lot of copies and meets user requirements . Justify which methods they should use to gather client requirements and why . [ 5 ] The original 2010 movie version of ' Scott Pilgrim vs. the World ' had Scott end up with Knives Chau instead of Ramona Flowers , but focus groups disliked that he spent the whole movie fighting for her for nothing , so it was changed . D id Y ou K now? 3.2 - Project Planning Tools Topic List 4.2 - Client Requirement Specifications