Secondary 5 Information & Communication Technology

A system linking two or more computers and peripherals with transmission media so they can share resources and exchange data.

A network confined to a room, office or building, such as a school computer room network.

A network spanning cities, countries or continents, formed by interconnecting LANs through routers; the internet is the largest example.

Copper cable made of wire pairs twisted together to reduce interference; the most common wired medium in LANs.

A hair-thin glass medium that carries data as light pulses; very high bandwidth, long distance and immune to electromagnetic interference.

The component that connects a computer to a network, converting data into signals sent over the medium.

A central device connecting hosts in a star layout; it broadcasts incoming data to every port, so efficiency is low.

A central connecting device that forwards data only to the port of the destination address, beating the hub in both efficiency and security.

A device joining two or more networks and routing data by destination address; the key to linking a LAN to the internet.

The geometric arrangement of nodes and links in a network; common forms are star, bus and ring.

A set of communication rules that devices on a network follow, such as IP, TCP and HTTP.

The protocol that addresses data packets and delivers them from the source network to the destination network.

The unique numeric identity of a device online; common IPv4 addresses have four numbers from 0 to 255 separated by dots.

The protocol working with IP: it numbers data segments and guarantees complete, in-order delivery, retransmitting any loss.

The system that resolves domain names into IP addresses so users need not memorise numbers.

The protocol fetching web pages between browser and web server in a request-and-response model, sending text in the clear.

The secure version of HTTP adding encryption and identity verification, essential for sensitive transfers such as payment and login.

The protocol that sends email from the sender to mail servers and on to the recipient's mail server.

The protocol that downloads mail from a mail server onto the user's device for reading.

The protocol for uploading and downloading files between client and server, widely used for website management and large files.

The language that marks up web page content and structure with tags; the foundation of web authoring.

A markup token naming the nature of content in HTML, appearing as a start and end pair, e.g. heading and paragraph tags.

Extra information written inside a start tag, e.g. a hyperlink's destination address or an image's source file.

A link jumping between pages or to a spot within a page, set by the link tag with its destination attribute.

Software that fetches pages from servers and renders HTML into the layout users view.

The entry page of a website, usually carrying an introduction and links to the other pages.

An authoring tool whose editing view matches the final page, generating HTML automatically as the author lays out.

A tool handling plain text only, letting the author type HTML tags directly for lean, controllable files.

Descriptive text shown when an image fails to load and read by screen readers, set in the image tag's attribute — part of accessible design.

The process of sending local files to a server; finished pages must be uploaded to a web server before publication.

A finite, unambiguous sequence of steps that solves a problem, turning inputs into outputs when executed in order.

A diagram of an algorithm using agreed symbols: terminal, input/output, process, decision and flow lines.

A textual way of writing algorithm steps in near-natural keywords, free of any specific programming language syntax.

The rounded-box symbol in a flowchart marking where the algorithm starts and ends.

The parallelogram symbol showing data entering the algorithm or results being output to the user.

The rectangle symbol representing processing steps such as assignment and calculation.

The diamond symbol selecting a follow-up path by whether a condition holds, with exits usually labelled Yes and No.

Arrowed lines connecting flowchart symbols and showing the order and direction of execution.

A named location holding data whose value may change during execution, such as a running total or counter.

A variable tallying how many times something has happened, commonly controlling loop counts, e.g. how many marks entered.

A named location holding data whose value may change while the program runs.

The act of storing a value or a computed result into a variable, e.g. setting total to total plus mark.

The control structure in which instructions execute one by one in written order; the most basic of the three.

The structure choosing a path by whether a condition holds, in single-way, two-way and multi-way forms.

The structure repeating a block of instructions, as a count-controlled loop with known repeats or a condition-controlled loop.

An expression built from comparison and logical operators, evaluating to true or false only, used in selections and loops.

The data type with only two values, true and false, underlying all condition testing.

A symbol performing an operation: arithmetic operators, comparison operators and logical operators (AND, OR, NOT).

A loop that never ends because its condition stays true, usually because the loop variable is never updated.

Placing one control structure inside another, e.g. a selection inside a loop, layering simple structures into complex logic.

Software designed to damage systems, steal data or extort money, including viruses, worms and Trojans.

Malicious code attached to files, spreading when an infected file is opened and causing damage.

An attack luring users to fake sites through spoofed messages, harvesting passwords, card numbers and other sensitive data.

Security hardware or software monitoring network traffic in and out and blocking suspicious connections by rules.

A tool detecting, blocking and removing malware; its virus definitions need regular updates to meet new threats.

Turning plaintext into ciphertext readable only with the right key, protecting the confidentiality of data.

A password that is long, mixes letter cases, digits and symbols, avoids personal data and is never reused across accounts.

Requiring a second credential, such as a one-time code, beyond the password at login, so leaked passwords alone cannot be abused.

Data identifying a living person directly or indirectly, such as name, phone number, address and identity card number.

Six principles under Hong Kong's Personal Data (Privacy) Ordinance governing collection, retention, use, security, transparency, and access and correction of personal data.