Digital systems

How computers work, without code. Short lessons on how data is stored as numbers, how networks move it and how it is kept safe. Each one is a board to try, a worked example and a few checks, for introducing an idea or revising it. They link to the coding lessons that put the same ideas to work.

Data representation

Bits and binary numbers, then text, colour, images and sound as numbers, then making data smaller.

Start here to see how a computer stores every number, letter, colour and sound as 0s and 1s.

Open the Data representation trail →

Networks and security

How data moves between computers, how it is kept safe, and how to protect your accounts and privacy.

Start here to follow a message across the internet and see what keeps it private.

Open the Networks and security trail →

Hardware and logic

What is inside a computer, and how simple on-off switches add up to logic.

Start here to open up a computer and build logic from switches.

Open the Hardware and logic trail →

The command line

Use a computer by typing, as on servers and Raspberry Pis.

Start here to run a computer the way servers are run: by typing.

Open the The command line trail →

Data representation

Bits and binary numbers, then text, colour, images and sound as numbers, then making data smaller.

Foundations

Data representationBits, binary numbers, and how many patterns a few bits can make.Everything a computer stores is numbers: text as character codes, pictures as pixels, sound as samples. Then how those numbers are stored with only 0s and 1s: binary place value, how many numbers a few bits can hold, logic gates, and the chain from any data down to bytes.

Extensions

Making data smallerSquash data and see what is lost.Compression for Years 9–10: why it matters, run-length encoding (store how many of each colour in turn, and get back exactly the same picture), and lossy compression, which throws away what we won't notice, for good.After: Data representation How a web page is madeWords, tags and style: three layers of every page.For Years 9–10: a web document is three layers, content, structure (HTML) and presentation (CSS). See each layer on its own, change one without touching the others, and find out why keeping them apart matters for whole sites, phones and screen readers. No coding needed; the HTML & CSS course puts it to work.After: Data representation

Networks and security

How data moves between computers, how it is kept safe, and how to protect your accounts and privacy.

Foundations

NetworksFollow a packet across the internet.How data travels between computers and how it is kept safe: wired and wireless links, packets and the TCP protocol, why data needs encrypting on the way, and the whole journey of a message across the internet. Then a capture the flag on the club's own network.Cyber safety and privacyKeep the club's app, and yourself, safe.You are the security officer for the Coding Club's new app. Years 7–8: why passwords fail, how a second factor protects an account, spotting phishing, and keeping a digital footprint small. Years 9–10: a threat model of the app, the three kinds of weakness, and the Australian Privacy Principles. Then a security review: find and fix every weakness to earn the flags. Everything is defensive and fictional.

Extensions

Capture the flagFind what's exposed before anyone else does.Years 8–10. Two skills a defender needs, then a capture the flag that uses everything: encoding is not encryption (binary, hex and base64 are public rules anyone can undo), and what your own web page gives away (comments, hidden fields, scripts and photo details reach every visitor). Then the old club archive: five flags found with decoding, page source, the command line, a tiny processor and a key word, and the leaks fixed before it closes. Defensive and fictional throughout.After: Cyber safety and privacy and Networks and How a web page is made Security and privacyWhat keeps your data safe, and what doesn't.For Years 9–10: how the operating system manages hardware and access, how names and addresses get data to the right computer, how sign-in and permissions decide who may do what, and how hashes and public keys protect passwords and messages. Then a capture-the-flag finale: find the weaknesses in a school portal and fix them.After: Networks

Hardware and logic

What is inside a computer, and how simple on-off switches add up to logic.

Foundations

Inside a computerProcessor, memory and storage: what makes it fast.For Years 7–8: what a computer's specifications measure (processor, RAM, storage, network, graphics), how each one affects how fast a job runs, finding the bottleneck, and choosing hardware for a job within a budget.

Extensions

From gates to a processorBuild a calculator from switches.For Years 9–10, after Data representation's logic gates lesson: combine gates into circuits, add binary numbers with full adders, store a bit in a latch, then run programs on a tiny processor clock tick by clock tick.After: Data representation and Inside a computer

The command line

Use a computer by typing, as on servers and Raspberry Pis.

Foundations

The command lineTalk to the computer in its own words.For Years 8–10: use a computer by typing commands, as people do on servers, Raspberry Pis and Linux and Mac computers. Move around folders, read and search files, change them, chain commands with pipes, and control who can read what. Everything runs on a pretend computer in the browser; a Raspberry Pi is the real thing.

Curriculum mapEvery Years 7–10 descriptor by strand and year: how they connect, and which have lessons.