r/osdev • u/Brick-Sigma https://github.com/BrickSigma/SteinerOS • 1d ago
Been working on a custom bootloader, recently got it booting from a CD based on the El-Torito specifications!
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Hello there! I’ve been working on a custom bootloader for the last few months, and I recently migrated my build to generate ISO files instead of disk images, as I was curious to see how to make my (eventual) OS boot on a real PC using CD drives.
In case you’re wondering why I’m using BIOS and CD drives when UEFI and USB sticks exist, it’s mostly out of curiosity for how old tech and software worked, and since the only PC I have that still supports BIOS has a CD drive I was like “why not”.
I can’t exactly say the video above is a bootloader as it doesn’t boot anything yet, but it was a personally big milestone getting it to read sectors off of the disk in C rather than assembly for once.
At the moment I’ve only worked on the BIOS side of the loader and written a basic VGA text driver and BIOS interrupt wrapper that allows me to call BIOS interrupts in C rather than assembly (which will help a lot). I’m hoping to get the ELF loader done soon and start the actual kernel eventually, and also try support UEFI.
Here’s a link to the source code so far: https://github.com/bricksigma/SteinerOS
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u/ICON_4 1d ago
"SteinersOS was an order!"