November, 2025

Writing an OS Kernel from Scratch – Part 23: Framebuffer — Run Your OS on a Graphical Interface! “VGA text mode can only display characters; a real graphical interface requires pixel-level control. Today, we implement the Framebuffer driver, enabling your OS to draw points, lines, rectangles, and even display images!” In previous posts, our output... » read more

Tiny Trick: Embedded Filesystem in Kernel — Stuffing init Right Into the Kernel Binary! When your kernel doesn’t yet support reading disks or filesystems, how do you support a simple filesystem in a temporary way? Today’s trick — compile the filesystem directly into the kernel! No disk needed, no driver needed, the kernel executes init... » read more

Writing an OS Kernel from Scratch | Windows GPT+UEFI Boot: ESP Partition, NVRAM Boot Entries & Secure Boot Explained The previous chapter covered MBR+BIOS mode Windows boot, where the System Reserved partition is the core anchor — BOOTMGR and BCD live in that 100MB FAT32 partition, and BIOS finds it via the MBR active partition... » read more

Writing an OS Kernel from Scratch – Part 2: Hello World Analysis “You think ‘Hello World’ is just printing a line? In an OS kernel, it hides the secrets of boot flow, memory layout, and hardware protocols.” In the previous post, we successfully had our kernel output “Hello from the kernel!” on QEMU. Looks simple,... » read more