Communication

Email (Electronic Mail) is a digital messaging system that allows users to send and receive messages and files over the internet. It operates on a 'store-and-forward' model, where messages are stored on servers until the recipient retrieves them. Email is used for personal chats, formal business communication, marketing, and sharing documents as attachments. While powerful, it comes with challenges, notably unsolicited mail (spam) and fraudulent attempts to steal information (phishing). Spam is unwanted bulk email, often advertising. Phishing emails are more dangerous, as they masquerade as legitimate messages to trick you into revealing sensitive data like passwords or bank details. Being able to identify and manage these threats is a key ICT skill.

The Internet is a vast, global network of interconnected computer networks. It allows billions of devices worldwide to communicate with each other. It's important not to confuse the Internet with the World Wide Web (WWW); the Web is just one of the services that runs on the Internet, like email and file transfer. Data doesn't travel in one piece. Instead, it is broken down into small, manageable chunks called 'packets'. This process is called packet switching. Each packet contains part of the data, the recipient's IP address (a unique address for every device on the internet), the sender's IP address, and information on how to reassemble the data. These packets are sent independently across the network via devices called routers, which choose the most efficient path for each packet. At the destination, the packets are reassembled into the original file or message.

A search engine is a software system designed to carry out web searches. It helps you find information on the World Wide Web. Search engines work in three main stages. First, 'crawling', where automated programs called spiders or bots follow links to discover web pages. Second, 'indexing', where the content of these pages (text, images, keywords) is stored and organised in a massive database. Third, 'ranking', where the search engine's algorithm analyses your query and returns a list of indexed pages, ranked in order of perceived relevance. However, not all information found online is accurate or reliable. It is crucial to evaluate online sources by considering their Credibility (who is the author?), Accuracy (is the information correct and verifiable?), Reasonableness (is it fair and unbiased?), and Support (are there citations or links to back up claims?).

A protocol is a set of rules that governs how data is formatted and processed for communication between devices. They are essential for ensuring devices can understand each other. Key internet protocols include: TCP/IP (Transmission Control Protocol/Internet Protocol), the fundamental suite that manages packet switching; HTTP (Hypertext Transfer Protocol), used to transfer data for web pages; HTTPS (HTTP Secure), a version of HTTP that encrypts data for security; and FTP (File Transfer Protocol), used for transferring files between computers. Using the internet involves risks, such as Malware (malicious software like viruses or spyware), hacking (unauthorised access to a system), and data interception (eavesdropping on data as it's transmitted). To mitigate these risks, we use security measures like antivirus software to detect and remove malware, firewalls to block unauthorised network access, and encryption (like that used by HTTPS) to make intercepted data unreadable.

Modern communication relies heavily on networks. A computer network is two or more computers connected together to share resources. A Local Area Network (LAN) covers a small geographical area, such as a single building like a school or office. The hardware is usually owned by the organisation. A Wide Area Network (WAN) covers a large geographical area, like a country or even the whole world, often by connecting multiple LANs together. The internet is the largest example of a WAN. WANs often use third-party infrastructure, like telephone lines or satellite links. For wireless connectivity, we use technologies like Wi-Fi and Bluetooth. Wi-Fi (Wireless Fidelity) is used to create a wireless LAN, providing high-speed internet access over a range of up to 100 metres. Bluetooth is a short-range wireless technology (around 10 metres) used to connect devices directly, such as a smartphone to wireless headphones or a keyboard to a computer, without needing a central network.