Building an operating system from scratch is one of the ultimate challenges for a software engineer. Recently, I came across BoltOS (hosted on GitHub at adriantips/boltossource), a fascinating 64-bit higher-half hobby operating system written entirely in C and Assembly.
Instead of just recycling legacy tutorials, BoltOS aims for a modern environment—skipping old limitations to support advanced hardware and even running Windows binaries natively.
Here is a quick breakdown of what makes this project so cool:
Dual Bootloaders: Supports both a custom legacy BIOS bootloader (entering long mode via unreal mode) and a UEFI bootloader (BOOTX64.EFI) handling GOP and memory maps, mapping the kernel to 0xFFFFFFFF80100000.
Modern Storage Stack: Features a generic block layer with functional drivers for ATA/IDE PIO, AHCI (SATA), and crucially, NVMe (featuring hardware MSI/MSI-X interrupts with polling fallback).
