July, 2025

Writing an OS Kernel from Scratch – Part 19: User and Kernel Address Space — Building Secure Virtual Memory Boundaries “All processes share kernel code, but must never peek at each other; user programs roam freely but cannot cross the boundary. Today, we design the higher-half kernel mapping, achieving perfect isolation and efficient sharing of... » read more

Writing an OS Kernel from Scratch – Part 28: Window Manager — Controlling Windows via Keyboard “No mouse? No problem! Real geeks control everything with the keyboard. Today, we implement a Window Manager (WM), moving and resizing windows via keyboard shortcuts!” In previous posts, we built a userspace Display Server, Launcher, and multiple applications, but... » read more

Writing an OS Kernel from Scratch – Part 18: Multi-core Support — Make Your OS Truly Parallel! “Single-core scheduling is just pseudo-concurrency; the real performance leap is multi-core! Today, we wake up all CPU cores and implement SMP (Symmetric Multi-Processing) support!” In the previous post, we implemented a preemptive scheduler, but all tasks still switched... » read more