Small Two Stage Bootloader and C Kernel

I know a lot about 16 real mode and boot sectors but not everything about it. I am doing this small project to learn even more, after all knowledge is power. This project will show you how to write a two stage boot loader written in NASM (Net-wide Assembler), also with a simple kernel written in pure C.

Screen Shots (Only posting 3 at once)

Build and Run Instructions

• Install required tools for Debian based distros below.

   sudo apt install -y build-essential gcc-multilib nasm qemu-system wodim
  

• How to compile?

   (NOTE: You need gcc-multilib to compile this now!)
  
   1 - make run (builds and runs in qemu).
   2 - make debug (builds and runs in qemu with gdb debugging).
   3 - make disk - builds floppy.img (you can write that to a floppy).
   4 - make cdrom - builds cdrom.iso (you can write this to cdrom).
  

• How to write to disk?

   1 - Floppy, make disk && sudo dd if=floppy.img of=/dev/fd0 bs=512 count=2880 conv=sync status=progress
   2 - CDROM, an ISO image ready to burn.
   	2a - cdrecord -scanbus (to see what device id).
   	2b - cdrecord dev=<devid> speed=12 -pad -v -eject boot32-barebones.iso
   	2c - NOTE: <devid> = #,#,# from cdrecord -scanbus (2a).
  

PATCHES

• None

Apply the patches like this!

	cd into boot32-barebones root directory then,
	git apply patches/<patch-name>.patch

TODO

• Check marks are already completed.

• - First stage boot loader (for loading second stage).

• - Second stage boot loader (for loading kernel).

• - Simple starter kernel written in C.

• - Add my simple file system (list of LBA starts and count of sectors).

• - Fix kernel not loading again.

• - Fix ISRs and IRQs so they work (they cause a kernel panic).

• - Fix breakpoint exception (shouldn't be happening).

• - Fix keyboard map.

• - Fix keyboard handler, it types multiples and '9' is enter for some reason.

• - Add PIT timer handler.

• - Add keyboard input handler.

• - Basic shell.

• - Fix buggy backspace issue.

• - Make backspace not exceed bounds. (Complete)

• - Fix bug with shift key in keyboard driver.

Known Issues

• (Fixed) Backspacing is normal now, works like a charm.
• (Not fixed) Keyboard driver has a bug when you press shift it stays on, caps lock doesn't effect it either. Will fix soon.

Developer

• Philip R. Simonson (aka 5n4k3)
• With help from people on osdev.org, Michael Petch, Octocontrabass, and more.

License

• MIT License (see LICENSE.md for details)