Learn how to use the style tags in an HTML document to edit the background colour and font text and colour. 9. Style (Colours & Fonts) HTML Guide Watch on YouTube: Before you add any colours or font styles, you need to add tags. The style tags must be written within your head of your HTML document! Add them below your title tags: Add the

Learn about the different protocols used on networks - HTTP, HTTPS, TCP, IP, FTP and SMTP. Also learn about protcol layers in the 4-layer TCP/IP model. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 3.2b: Protocols & Layers Exam Board: OCR Specification: J277 Watch on YouTube : IP & MAC Addresses Protocols & Standards Common Protocols Protocol Layers Protocols A protocol is a set of rules that allow devices on a network to communicate with each other . TCP / IP (Transmission Control Protocol / Internet Protocol) TCP / IP is actually two separate protocols that combine together. TCP is a protocol that allows packets to be sent and received between computer systems. It breaks the data into packets and reorders them back into the original data at the destination. IP is a protocol in charge of routing and addressing data packets . This ensures data packets are sent across networks to the correct destination . It is also an addressing system - every device on a network is given a unique IP address so data packets can be sent to the correct computer system. HTTP is used to transfer web pages over the Internet 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 (Hypertext Transfer Protocol) Transfer Protocols FTP ( File Transfer Protocol ) is used to transfer files across a network. It is commonly used to upload or download files to/from a web server . SMTP ( Simple Mail Transfer Protocol ) is a protocol used to send emails to a mail server and between mail servers . POP ( Post Office Protocol ) and IMAP (Internet Message Access Protocol ) are both protocols for receiving and storing emails from a mail server. POP will delete an email from the email server once it has been downloaded to a device . Pop! IMAP syncs the message with an email server so it can be accessed by different devices . IP Address & MAC Address There are two versions of IP addressing currently used - IPv4 and IPv6 . IPv4 is a 32-bit address , represented in denary , that allows for over 4 billion unique addresses . It has four 8-bit segments of denary values (from 0 to 255) separated by full stops . IPv4 example: 145.13.218.102 IPv6 is a 128-bit address , represented in hexadecimal , that allows for an undecillion unique addresses . It has eight 16-bit segments of four hexadecimal values (0000 - FFFF), separated by colons . IPv6 example: 736E:1029:A4B3:902D:77B2:72FF:AE62:0912 A MAC address is a unique hexadecimal number assigned to each network interface card/controller inside a networked device such as a router or laptop . A MAC address is a 48-bit address made up of six 8-bit pairs in hexadecimal , separated by dashes . While an IP address may change , the MAC address can’t be changed . MAC stands for Media Access Control . Network Interface Card (NIC) MAC example: 19-C2-D1-47-AA-38 Networking Standards Networking standards are rules that allow computer systems to communicate across networks . Standards have been created to ensure devices can exchange data and work together by interpreting signals in the same way , regardless of the manufacturer . TCP/IP Stack & Layers What is TCP/IP? TCP/IP (Transmission Control Protocol / Internet Protocol ) is a set of protocols that operate on different layers . These two protocols are used together to allow computers to communicate on a network . What is a protocol layer? A layer is a division of network functionality - each layer provides a specific function to assist the transmission of the data that is being sent. TCP/IP is split into four layers (named Application , Transport , Internet and Link ). Important Note: You do not need to know any layer names or the purpose of any specific layers in the OCR GCSE J277 specification , just what layers are and why they’re used . Why are protocol layers used? Layers are self-contained , so they allow different developers to concentrate on one aspect of the network at a time . A layer can be taken out and edited without affecting other layers . Protocol layers are used to visualise the different parts of a network , as each of the four layers of TCP/IP has a specific role and is associated with different protocols . Protocols are broken down into well-defined , specific layers to simplify design , making it easier to identify errors (known as troubleshooting ). Each layer uses specific protocols , so layering ensures these protocols are applied in a specific order . This process uses abstraction and layers only communicate with adjacent layers for easy compatibility . Q uesto's Q uestions 3.2b - Protocols & Layers: 1. Describe each of the following protocols . It might be helpful to also draw an icon or small diagram for each one: a. TCP [ 2 ] b. IP [ 2 ] c. HTTP & HTTPS [ 3 ] d. FTP [ 2 ] e. SMTP [ 2 ] f. POP3 & IMAP [ 2 ] 2. State which protocol would be used in the following scenarios : a. Transferring a music file to a friend over the internet. [ 1 ] b. Sending an email to a family member in America. [ 1 ] c. Using a webpage to enter a password securely. [ 1 ] d. Receiving an email from a bank. [ 1 ] 3a. What are networking standards ? [ 2 ] 3b. What is TCP/IP ? [ 2 ] 3c. What is a protocol layer ? [ 2 ] 3d. Give at least two reasons why protocols are split into layers . [ 4 ] 3.2a - Wired & Wireless Networks Theory Topics 4.1 - Security Threats

Test your understanding of working with files in Python, including reading, searching, writing and editing. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. Python - Section 10 Practice Tasks Task One Create a file in Python called DaysOfTheWeek.txt. Write the days of the week into the file in a single print line but put each day on a new line. Check the file to see if it has worked. Example solution: Task Two Create a file called Colours.txt. Use a for loop to ask the user to enter 8 different colours. Write each colour onto the same line, with a space between the colours. Close the file and open it again in read mode and print it. Example solution: Task Three Create a file named "Holiday.txt". Ask the user to enter the family name, destination and and number of passengers. Print each family's details on their own line. Bonus: Edit this program to add a search feature to look for the family name. Example solution: Task Four Use the holiday file from task three above. You are going to change the destination. Ask the user to enter a family name and then a new destination. Update the destination with the new value. Check the file to ensure the destination has been updated successfully. Use section 10c to help you with this task. Example solution: ⬅ 10c - Remove & Edit Lines 11 - Graphical User Interface ➡

Navigate between all Unit 1 (Fundamentals of IT) topics in the OCR Cambridge Technicals Level 3 IT 2016 specification. OCR Cambridge Technicals IT Level 3 Unit 1: Fundamentals of IT These pages are based on content from the OCR Cambridge Technicals 2016 Level 3 IT specification . This website is in no way affiliated with OCR . This qualification stopped in July 2025. The pages on the site will remain for at least two years. LO1 (Computer Hardware ) 1.1 - Computer Hardware 1.2 - Computer Components 1.3 - Types of Computer System 1.4 - Connectivity 1.5 - Communication Hardware 1.6 - Hardware Troubleshooting 1.7 - Units of Measurement 1.8 & 1.9 - Number Systems & Conversion LO2 (Computer Software ) 2.1 - Types of Software 2.2 - Applications Software 2.3 - Utility Software 2.4 - Operating Systems 2.5 - Communication Methods 2.6 - Software Troubleshooting 2.7 - Protocols LO3 (Networks & Systems ) 3.1 - Server Types 3.2 - Virtualisation 3.3 - Network Characteristics 3.4 - Connection Methods 3.5 - Business Systems LO4 ( Employability & Communication ) 4.1 - Communication Skills 4.2 - Communication Technology 4.3 - Personal Attributes 4.4 - Ready for Work 4.5 - Job Roles 4.6 & 4.7 - Bodies & Certification LO5 (Issues & Security ) 5.1 - Ethical Issues 5.2 - Operational Issues 5.3 - Threats 5.4 - Physical Security 5.5 - Digital Security 5.6 - Data & System Disposal

Learn about the different protocols used on networks - HTTP, HTTPS, TCP, IP, Ethernet, WiFi, FTP and SMTP. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.5: Protocols Exam Board: Eduqas Specification: 2020 What is a protocol? A protocol is a set of rules that allow devices on a network to communicate with each other . TCP / IP is actually two separate protocols that combine together. TCP / IP (Transmission Control Protocol / Internet Protocol) TCP is a protocol that allows packets to be sent and received between computer systems. It breaks the data into packets and reassembles them back into the original data at the destination. IP is a protocol in charge of routing and addressing data packets . This ensures data packets are sent across networks to the correct destination . It is also an addressing system - every device on a network is given a unique IP address so data packets can be sent to the correct computer system. HTTP is used to transfer web pages over the Internet 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 (Hypertext Transfer Protocol) Ethernet is a protocol for wired connections . Ethernet is used at both the data link and physical layers to describe how network devices can format data packets for transmission. WiFi is the main standard for wireless connections . WiFi is actually a brand name that uses a protocol called IEEE 802.11 . Another wireless standard is Bluetooth , for short-range data transfer. Connection Protocols Transfer Protocols FTP ( File Transfer Protocol ) is used to transfer files across a network. It is commonly used to upload or download files to/from a web server . SMTP ( Simple Mail Transfer Protocol ) is a protocol used to send emails to a mail server and between mail servers . Q uesto's Q uestions 3.5 - Protocols: 1. Describe each of the following protocols . It might be helpful to also draw an icon or small diagram for each one: a. TCP [ 2 ] b. IP [ 2 ] c. HTTP & HTTPS [ 3 ] d. WiFi (802.11) [ 1 ] e. Ethernet [ 2 ] f. FTP [ 2 ] g. SMTP [ 2 ] 2. State which protocol would be used in the following scenarios : a. Transferring a music file to a friend over the internet. [ 1 ] b. Sending an email to a family member in America. [ 1 ] c. Using a wireless connection to play a mobile game. [ 1 ] d. Using a webpage to enter a password securely. [ 1 ] e. Watching a video on YouTube. [1 ] 3.4 Network Hardware & Routing Theory Topics 3.6 - 7 Layer OSI Model

Learn about applications, utility software, open source and closed source, translators including interpreters, compilers and assemblers, stages of compilation (lexical analysis, syntax analysis, code generation and optimisation) and linkers, loaders and libraries. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 2.2 - Applications Generation Specification: Computer Science H446 Watch on YouTube : Application software Utilities Open & closed source High & low level language Translators Stages of compilation Linkers, loaders & libraries This topic explores key types of software and how they support computer systems and users . It explains different kinds of applications , utilities , translators and compares open and closed source software . Another important concept is compilation , with knowledge required of its different stages , as well as linkers , loaders and software libraries . Applications Software Applications software allows users to carry out productive or creative activities such as document editing , data analysis , communication or media creation . Common examples include word processors (e.g. Microsoft Word or Google Docs ), spreadsheets (e.g. Excel or Sheets ), database management systems (e.g. Access ), web browsers (e.g. Chrome or Safari ) and graphics editors (e.g. Photoshop ). Applications can be general-purpose , serving many uses , or special-purpose , created for a specific function like payroll or medical record management . Utilities Utility software is system software designed to maintain , optimise and manage a computer’s performance , often running in the background to support the operating system . Examples include security tools like an antivirus , backup , compressors , disk management utilities and defragmenters . Defragmentation is the process of reorganising files on a hard drive so that parts of each file are stored together in contiguous blocks , improving access speed . Open Source & Closed Source Open source software has its source code (the actual code written by its developers ) made publicly available , allowing users to view , modify and share it freely . An open source licence encourages collaboration , transparency and community-driven improvement . However, it may lack official technical support or guaranteed updates . Closed source software has its source code private , restricting modification and redistribution . It is usually sold commercially with paid licences , regular updates and dedicated technical support . Bug fixes and quality assurance are out of the user's control , being managed by the developer . Support may end without warning . High & Low Level Languages Programming languages can be split into high-level and low-level , based on how close they are to the computer’s hardware . High-level languages are easier to read and write , while low-level languages give direct control over hardware but are harder to use . High-level languages like Python or Java are similar to natural human language, making them easy to write , understand, and debug . Low-level languages include machine code (binary ) and assembly language but are written for specific processor architecture . Translators Translators are programs that convert source code written in one programming language into another form that the computer's CPU can understand - typically machine code (binary ). An assembler translates assembly language into machine code that the CPU can execute directly . An interpreter translates and executes high-level code in a line-by-line method, stopping when an error occurs . A compiler translates the entire high-level program into machine code before execution , producing an executable file . Stages of Compilation Compilation is a complicated process to convert high-level program code into machine code . It consists of four key stages : Lexical analysis breaks the source code into tokens , such as keywords , identifiers and operators . Spaces and comments are removed and a symbol table of identifiers is created. Syntax analysis checks that the token sequence follows the grammatical rules of the programming language , building an abstract syntax tree . Code generation converts the abstract syntax tree into object code (unfinished machine code ) the CPU can understand . Code optimisation improves the efficiency of the generated code , for example by reducing redundant instructions or improving execution speed . Libraries, Linkers & Loaders Compilation also requires additional programs, such as a linker and loader and the use of libraries . A library is a collection of pre-written code created by other programmers that contains useful routines and functions which can be reused in a program. A linker combines object code and libraries , resolving references so that a final executable file can be created . A loader copies an executable file from secondary storage into RAM , ready for execution by the processor . Q uesto's K ey T erms Applications: database, word processor, web browser, graphics manipulation, spreadsheet software, presentation software Utilities: defragmentation, system cleanup, file manager, device driver, security tools Open & Closed Source: source code, open source, closed source Translators: assembler, interpreter, compiler, machine code Stages of Compilation: lexical analysis, token, syntax analysis, abstract syntax tree, code generation, code optimisation, library, linker, static linking, dynamic linking, loader D id Y ou K now? Grace Hopper , a US Navy rear admiral , is credited with creating one of the first compilers in 1952 and coining the term ' compiler '. She also helped develop the languages FLOW-MATIC and later COBOL , which is still used today . 2.1 - Systems Software A-Level Topics 2.3 Software Development

Learn about legislation and regulations related to application development, including the Data Protection Act, Computer Misuse Act and Freedom of Information Act. 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 Watch on YouTube: Computer Misuse Act Data Protection Act UK General Data Protection Regulation Freedom of Information Act Privacy and Electronic Communications Regulations Independent bodies UK Information Commissioner's Office 6.1 - Legal Considerations You need to know the latest version and main purpose of each act /regulation , as well as actions taken to comply with the act and the impacts of not complying with it. You must also understand how Privacy and Electronic Communications Regulations (PECR ) relate to the Data Protection Act and UK General Data Protection Regulation (UK GDPR ), and the role of the Information Commissioner's Office (ICO ) in the UK. What You Need to Know Developers must ensure application software complies with relevant legislation and regulations to protect users , their data and computer systems and to avoid legal and financial consequences . Computer Misuse Act (CMA) The Computer Misuse Act (CMA ) protects computer systems and data from unauthorised access and misuse . It makes activities such as unauthorised access , hacking and deliberately impairing computer systems criminal offences . Developers must only access systems and data they have permission to use , ensure any security testing is authorised , and must not develop or use software to deliberately gain unauthorised access or damage systems . If individuals do not comply with the CMA , they could face criminal prosecution , fines or imprisonment , while an organisation could also experience financial costs and reputational damage . Example : A developer must have permission before attempting to access restricted parts of a client's system , even if they claim they were only testing its security . Data Protection Act (DPA) The purpose of the Data Protection Act (DPA ) is to control how organisations collect , process , store and protect personal data . It helps ensure people's (known as data subjects ) information is handled fairly , lawfully and securely . Developers should ensure applications only collect necessary personal data , explain how it will be used , only use it for its intended purpose , keep it secure and remove it when it is no longer required . Non-compliance can result in complaints , data breaches , regulatory action , legal disputes , financial penalties , operational disruption and reputational damage . Example : A revision application should not collect a student's home address if that information is unnecessary for providing the service. UK General Data Protection Regulation (UK GDPR) UK General Data Protection Regulation (UK GDPR ) provides rules and principles governing the lawful processing and protection of personal data . It gives individuals rights over how organisations use their information . It operates alongside the DPA 2018 in the UK . Developers should ensure there is a lawful reason for processing personal data , collect only necessary information , clearly explain its use , keep it accurate and secure , avoid retaining it unnecessarily and allow users to exercise their data rights where applicable. If they do not comply , organisations can face investigations , enforcement action , significant fines , compensation claims and reputational damage , particularly following serious data breaches . Example : A bank application collecting account information should clearly tell users what personal data is collected and why it is needed . Freedom of Information Act (FOIA) The Freedom of Information Act (FOIA ) gives people the right to request recorded information held by public authorities , such as government departments , councils , state schools and the NHS , subject to exemptions . To comply , when developing software for a public authority , developers should consider how information can be stored , organised , searched and retrieved so the organisation can respond appropriately to information requests . Non-compliance may cause a public authority to face complaints , investigations , enforcement action and reputational damage if it fails to meet its legal responsibilities . Example : A system developed for a council should allow relevant recorded information to be located when the council receives a valid FOI request . Privacy and Electronic Communications Regulations (PECR) Privacy and Electronic Communications Regulations (PECR ) protect people's privacy when using electronic communications , including rules covering electronic marketing , cookies and similar technologies and the security of communications services . To comply, developers may need to ensure applications obtain appropriate consent for non-essential cookies or similar technologies , provide relevant information to users and follow the rules when enabling electronic marketing such as emails or text messages . If they don't comply , organisations could face regulatory action , financial penalties , complaints and reputational damage . Example : A website should not simply place certain advertising or analytics cookies on a user's device without providing the required information and obtaining consent where required. Independent Bodies Independent bodies are organisations that operate separately from the organisations they oversee and can provide guidance , monitor legal compliance and take action when rules or standards are not followed . When developing application software , independent bodies may: Provide guidance and codes of practice that developers can follow. Monitor and investigate whether organisations are meeting their legal responsibilities . Handle complaints from users or members of the public . Take or recommend enforcement action when organisations fail to comply . Help developers understand how legislation should be applied to applications and user data . Information Commissioner's Office (ICO) The Information Commissioner's Office (ICO ) is the UK's independent regulator for information rights and data protection , overseeing areas including the DPA , UK GDPR , FOIA and PECR . When developing application software , the ICO is relevant because it: Provides guidance on how personal information should be collected , processed , stored and protected . Helps organisations understand how to comply with data protection and privacy legislation . Can investigate complaints and data breaches . Can take enforcement action when organisations fail to meet their legal obligations . Promotes good practice in areas such as privacy , electronic marketing , cookies and protecting users' information . Example : If developers create an application that collects users' names , email addresses and dates of birth , they can use ICO guidance to help ensure the application handles this personal data appropriately and complies with data protection requirements . Q uesto's Q uestions 6.1 - Legal Considerations: 1. State the main purposes of the CMA , DPA , UK GDPR , FOIA and PECR . [ 2 each ] 2. For each act or regulation , explain the actions developers should take to ensure application software complies with its requirements . [2 each ] 3. Explain the possible impacts on an organisation if its application software does not comply with relevant legislation or regulations . [2 each ] 4. Explain the role of independent bodies and the Information Commissioner's Office (ICO ) when developing and operating application software. [4 ] 5. A revision app collects users' personal data , uses cookies and sends marketing emails . Identify the relevant legislation and explain how the developers should comply with it. [4 ] Following a 2018 cyberattack , personal data belonging to more than 400,000 British Airways customers was compromised . In 2020 , the Information Commissioner's Office ( ICO ) fined British Airways £20 million for failing to adequately protect its customers' data , the largest data protection fine the ICO has issued. D id Y ou K now? 5.3 - Policies Topic List

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 the three main types of secondary storage - magnetic, optical and solid-state. Also, learn about the characteristics of secondary storage media including reliability and durability. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 2.2: Secondary Storage Exam Board: OCR Specification: J277 Watch on YouTube : Secondary Storage Six Characteristics Magnetic Storage Optical Storage Solid State Storage Secondary storage is non-volatile storage used to save and store data that can be accessed repeatedly. Secondary storage is not directly embedded on the motherboard (and possibly even external ) and therefore further away from the CPU so it is slower to access then primary storage . Storage Characteristics you should know: CAPACITY : The maximum amount of data that can be stored on the device. DURABILITY : The strength of the device, to last without breaking . PORTABILITY : How easy it is to carry the device around . ACCESS SPEED : How quickly data on the device can be read or edited . COST : The average price it costs to purchase the storage device. RELIABILITY : The likelihood of the device continuing to perform well over time . Magnetic Storage A magnetic hard disk drive (HDD ) is the most common form of secondary storage within desktop computers. A read/write head moves nanometres above the disk platter and uses the magnetic field of the platter to read or edit data. An obsolete (no longer used) type of magnetic storage is a floppy disk but these have been replaced by solid state devices such as USB sticks which are much faster and have a much higher capacity. Another type of magnetic storage that is still used is magnetic tape . Magnetic tape has a high storage capacity but data has to be accessed in order (serial access ) so it is generally only used by companies to back up or archive large amounts of data . Magnetic Storage Characteristics (Hard Disk Drive): ✓ - Large CAPACITY and cheaper COST per gigabyte than solid state . ✓ - Modern external HDDs are small and well protected so they are DURABLE and PORTABLE , however because of the moving parts, they should not be moved when powered on because it can damage the device. X - Slower ACCESS SPEED than solid state but faster than optical storage . Optical Storage Optical storage uses a laser to project beams of light onto a spinning disc, allowing it to read data from a CD , DVD or Blu-Ray . This makes optical storage the slowest of the four types of secondary storage. Disc drives are traditionally internal but external disc drives can be bought for devices like laptops. Magnetic Disks are spelled with a k and Optical Discs have a c. Optical Storage Characteristics: X - Low CAPACITY : 700 MB (CD ), 4.7 GB (DVD ), 25 GB (Blu-ray ). X - Not DURABLE because discs are very fragile and can break or scratch easily. ✓ - Discs are thin and very PORTABLE . Also very cheap to buy in bulk. X - Optical discs have the Slowest ACCESS SPEED . Solid State Storage There are no moving parts in solid state storage. SSD s (Solid State Drives ) are replacing magnetic HDDs (Hard DIsk Drives) in modern computers and video game consoles because they are generally quieter , faster and use less power . A USB flash drive ( USB stick ) is another type of solid state storage that is used to transport files easily because of its small size. Memory cards , like the SD card in a digital camera or a Micro SD card in a smartphone , are another example of solid state storage. Solid State Characteristics: X - More expensive COST per gigabyte than magnetic . ✓ - Usually DURABLE but cheap USB sticks can snap or break . ✓ - The small size of USB sticks and memory cards mean they are very PORTABLE and can fit easily in a bag or pocket. ✓ - Solid State storage have a high CAPACITY and the fastest ACCESS SPEED because they contain no moving parts . Q uesto's Q uestions 2.2 - Secondary Storage: 1. Rank magnetic , optical and solid-state storage in terms of capacity , durability , portability , speed and cost . For example, magnetic has the highest capacity , then solid-state, then optical. This could be completed in a table . [15 ] 2. Justify which secondary storage should be used in each scenario and why it is the most appropriate: a. Sending videos and pictures to family in Australia through the post . [ 2 ] b. Storing a presentation to take into school . [ 2 ] c. Storing project files with other members of a group to work on together . [ 2 ] d. Backing up an old computer with thousands of files to a storage device. [ 2 ] 2.1 - Primary Storage Theory Topics 2.3 - Data Units

Learn about how to convert between the denary (decimal), binary and hexadecimal number systems. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). Exam Board: OCR 2.4a: Number Systems Specification: J277 Watch on YouTube : Binary and Denary Hexadecimal Number System Ranges Binary to Denary Denary to Binary Binary to Hexadecimal Hexadecimal to Binary Denary to Hexadecimal Hexadecimal to Denary What is binary? By now you should know that computer systems process data and communicate entirely in binary . Topic 2.3 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 . 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 . Binary & Denary Convert from binary to denary: Convert from denary to binary: Hexadecimal 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 . 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, 100111101011 in binary is 9EB in hexadecimal. Hexadecimal only uses single-character values. Double-digit numbers are converted into letters - use the table on the right to help you understand. Binary to hexadecimal: Hexadecimal to binary: Converting from denary to hexadecimal / hexadecimal to denary To convert from denary to hexadecimal or from hexadecimal to denary , it is easiest to convert to binary first . However, it is possible to convert directly from denary to hexadecimal or directly from hexadecimal to denary . The videos below explain both methods . Denary to hexadecimal: Hexadecimal to denary: Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube Q uesto's Q uestions 2.4a - 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 b. 11011011 c. 01011101 d. 11101110 e. 01011111 [1 each ] 3. Convert the following values from denary to binary : a. 35 b. 79 c. 101 d. 203 e. 250 [1 each ] 4. Convert the following values from binary to hexadecimal : a. 11110101 b. 01100111 c. 10111010 d. 10010000 e. 11101001 [1 each ] 5. Convert the following values from hexadecimal to binary : a. C2 b. 8A c. DE d. 54 e. F7 [1 each ] 6. Convert the following values from denary to hexadecimal : a. 134 b. 201 c. 57 d. 224 e. 101 [1 each ] 7. Convert the following values from hexadecimal to denary : a. 32 b. A5 c. 88 d. C0 e. BE [1 each ] Click the banners below to try self-marking quizzes (Google Forms) on these topics. Binary to Denary: Denary to Binary: Binary to Hexadecimal: Hexadecimal to Binary: 2.3 - Data Units Theory Topics 2.4b - Binary Addition & Shifts

Learn about the main character sets - ASCII (American Standard Code for Information Interchange) and Unicode. Also, discover the five data types - character, string, integer, real and Boolean. Based on the 2020 Eduqas (WJEC) GCSE specification. 4.5: Character Sets & Data Types Exam Board: Eduqas Specification: 2020 What is a Character Set? A character set is a table that matches together a character and a binary value . Character sets are necessary as they allow computers to exchange data . Two common character sets are ASCII and Unicode . ASCII Unicode ( American Standard Code for Information Interchange ) 0100 0001 0100 0010 0100 0011 Uses Binary 128 Tiny Set of Characters Less Memory Required Per Character U+0042 U+0055 U+004E Uses Hexadecimal 36,536+ Large Set of Characters More Memory Required per Character What are the different data types? When programming, variables should be given appropriate data types . Character String Integer A single character , such as a letter, number or punctuation symbol. Examples: A sequence of characters , including letters, numbers and punctuation. Examples: A whole number . Examples: T 8 ? Harry Waters 14:50pm Ice Age 4 475 -8432 56732 Real Boolean Telephone numbers are always stored as a string , not an integer. True / False Yes / No 0 / 1 An answer that only has two possible values . Examples: A decimal number . Examples: 65.3 -321.1234 909.135 Be careful with punctuation. 32.10 is a real but £32.10 is a string. Q uesto's Q uestions 4.5 - Character Sets & Data Types: 1. What is a character set and why are they needed ? [ 2 ] 2. Describe 3 differences between ASCII and Unicode . [6 ] 3. State the 5 different data types . [ 5 ] 4. State which data type is most suitable for the following variables: a. Age [ 1 ] b. Surname [ 1 ] c. Height (in metres) [ 1 ] d. First Initial [ 1 ] e. Phone number [ 1 ] f. Right-Handed? [ 1 ] 4.4 Arithmetic Shift Theory Topics 4.6 - Graphical Representation

Learn how pseudocode and flowcharts are written as part of algorithms. This content is based on the 2016 Eduqas / WJEC GCSE Computer Science specification. Algorithms Pseudocode Pseudocode Pseudocode is not a specific programming language but a more general method of describing instructions . It should be unambiguous, and it should not resemble any particular kind of programming language (e.g. Python or Java), so it can theoretically be turned into real code in any language. Generally, pseudocode can be written in any way that is readable and clearly shows its purpose. However, the Eduqas exam board advises that pseudocode for the programming exam should follow the conventions below : Annotation { Write your comment in curly brackets} Define data type price is integer firstname is string Declare a variable's value set price = 100 set firstname = "Marcella" Input / output output "Please enter your first name" input firstname Selection (must have indentation) if firstname = "Steven" then output "Hello" + firstname elif firstname = "Steve" then output "Please use full name" else output "Who are you?" end if Iteration (while loop) while firstname ! = "Steven" output "Guess my name." input firstname repeat Iteration (for loop) for i in range 10 input item next i Define a subroutine Declare Sub1 [Subroutine content indented] End Sub1 Call a subroutine call Sub1 Flowcharts flowchart A flowchart can be used to visually represent an algorithm. The flowchart symbols are: Algorithm Example example Pseudocode {This is a program to see how many items you can buy in a supermarket before you spend over £100} total is integer, itemsentered is integer, itemprice is integer set total = 0 set itemsentered = 0 while total < 100 output "enter the price of the next item" input itemprice total = total + itemprice itemsentered = itemsentered + 1 repeat if itemsentered >= 20 then output "You are on your way to saving money." elif itemsentered => 30 then output "You're a real money saver." else output "Look for better deals next time." end if Stop Flowchart