Systems
How computers actually work, from bytes in memory to processes managed by the kernel.
The lessons follow a deliberate progression. Memory (how the stack, heap, and virtual memory give every program its own address space), processes (how the kernel creates, schedules, and isolates running programs), the kernel (the boundary between your code and the hardware), threads and concurrency (how programs do multiple things at once), syscalls (the interface between user programs and the kernel), and how context switching works (the cost of multitasking).
Each lesson builds on the one before it. The glossary defines every term used across the lessons. The FAQ answers common questions that span multiple topics.
Lessons
1How Memory Works — Stack, Heap, and Virtual Memory2How Processes Work — Programs in Motion3How the Kernel Works — The Layer Between Your Code and the Hardware4How Threads Work — Concurrency Within a Process5How File Systems Work — Organizing Data on Disk6How Containers Work — Isolation Without Virtual Machines7Systems FAQ