Beginner · 5h 39m · 22 lessons
Computer Science Basics
See how computers think, store and solve problems. Plain words, no maths degree required.
What you'll learn
- ✦Explain what a computer is and what the CPU, memory and storage each do
- ✦Explain how text, numbers, images and sound all become patterns of ones and zeros
- ✦Count in binary and convert small numbers between binary and decimal
- ✦Explain how bits, bytes and codes like ASCII and Unicode store text and numbers, and work with KB, MB and GB
- ✦Trace how a program goes from source code to instructions the CPU runs, and compare compiled with interpreted languages
- ✦Explain what an operating system does and why every device needs one
- ✦Spot what makes a list of steps an algorithm, and explain why one task can have fast and slow solutions
- ✦Predict how a method’s work grows as the data grows (Big-O, without heavy maths), and tell data apart from information
- ✦Trace the CPU’s fetch-decode-execute cycle, rank the memory hierarchy by speed and size, and work out logic gate outputs
- ✦Explain abstraction, why sorted data is quicker to search, and which problems no computer can solve
Part of these career paths
- Absolute Beginner path · course 2 of 6
- CS Foundations path · course 1 of 5
Certification projects
Build 3 projects to earn your certificate
Hands-on work that proves you can apply what you learned — part of the certificate requirements.
Syllabus
Module 1 · 1h
What is a computer? Free
What you'll be able to do
- Can name the job of the CPU, RAM, storage and the input and output parts in any phone or laptop
- Can work out a task’s time from a CPU’s clock speed, and say when extra cores help
- Can explain why unsaved work vanishes, and whether a problem needs RAM or storage
- Can sort things into hardware and software, and tell which kind of fix a fault needs
Module 2 · 1h 6m
How data is represented Locked
What you'll be able to do
- Can explain why computers use two states, and count the patterns a row of bits can make
- Can convert numbers between binary and decimal using doubling column values
- Can convert between bits, bytes, KB, MB and GB, including Mbps download speeds
- Can encode and decode text with ASCII, and explain how Unicode lets emoji travel between phones
Module 3 · 1h 4m
How programs run Locked
What you'll be able to do
- Can tell source code from machine code and output, and predict what a literal computer does with steps in the wrong order
- Can explain what a compiler and an interpreter each do, and compare their total time over many runs
- Can name the main jobs of an operating system, and explain why apps ask it to use hardware
- Can trace what happens between a click on an app icon and its window appearing
Module 4 · 1h 7m
Thinking like a computer Locked
What you'll be able to do
- Can check whether a list of steps is a real algorithm: an input, clear steps, an output and a stop
- Can choose linear or binary search for a list and estimate the checks each one needs
- Can predict how O(1), O(log n), O(n) and O(n²) work grows when the data grows
- Can pick the processing that turns raw data into information for a given question
Module 5 · 41m
Inside the machine Locked
What you'll be able to do
- Can trace a short program through the CPU's fetch, decode, execute loop
- Can rank registers, cache, RAM and SSD by speed and size, and explain why a full RAM slows a laptop
- Can work out AND, OR, NOT and XOR outputs and add two bits with gates
Module 6 · 41m
Big ideas in CS Locked
What you'll be able to do
- Can spot an abstraction's interface and explain why changing its inside doesn't break the layers above
- Can decide when sorting first pays off, from the cost of sorting and of each search
- Can tell an intractable problem from an undecidable one, and say what real software does about each