Booted my first kernel today. It’s just a black screen with a white “F” in the corner, but it’s my black screen with my white “F”, printed by code I wrote, with no OS underneath.

What I built

• A cross-compiler from source. i686-elf-gcc doesn’t exist on a normal Linux install, you build it yourself from binutils + gcc source, targeting a “fake” freestanding platform (no OS, no libc assumed).
  I wrote the whole build script in bash, which I’d genuinely never written before this project.

• A Multiboot2 header (boot.s, NASM assembly) the exact magic number, checksum, and end tag GRUB looks for to recognize a bootable kernel. Also set up a stack (the CPU doesn’t give you one for free) and the _start entry point that hands off from assembly into C.

• A linker script (linker.ld) that tells the linker to load the kernel at 1MB — the first chunk of physical memory not already claimed by legacy BIOS/VGA stuff.

• kernel.c — writes directly to the VGA text buffer at physical address 0xB8000 (2 bytes per character: ASCII + color attribute). No printf, no stdlib, just a raw pointer and a cast.

Look forward for the next steps