study-kernel

A small kernel in nim, started as a fork of @dom96 's nimkernel

It is also inspired by Samantha Doran 's Mero : credits to them! However I wanted to know learn how this gdt etc stuff happens and write it down in a library and to stop using the Mero source

It is also based on many osdev and other internet articles:

• Writing an OS in Rust by Philipp Oppermann
• How to create an OS from scratch repo by Carlos Fenollosa
• and others TODO

why

Praise God! learning and building things is just fun and i want to somehow learn a bit more about os dev and language <=> os combinations.

structure

TODO structure

start.nim => contains kmain and registers the main code for now console.nim => a console utils module mostly from nimkernel by @dom96 ioutils.nim => a console ioutils module with code mostly from nimkernel by @dom96 iirc panicoverride.nim => a panic override module with code mostly from nimkernel by @dom96 or Mero by Samantha Doran, not sure asm/ => assembly sources needed for the kernel, most of them are from nimkernel/Mero or osdev c/ => c sources needed for the kernel build/ => build files

Dockerfile => dockerfile for kernel nim.cfg => nim config build_nim.sh => a build script linker.ld, linker2.ld => linker files, not sure which one is important nakefile.nim => older nake file based on nimkernel / Mero stuff IIRC

LICENSE => study-kernel current GPL3 license Mero_LICENSE => Mero GPL3 license nimkernel_LICENSE => nimkernel MIT license

asm/:

• boot.s: taken from Mero i think
• crti.s: from Mero(maybe osdev?) crtbegin stuff
• ctrn.s: from Mero(maybe osdev?) ctrend stuff?
• a.s: not sure, maybe test

c/:

• libc.c: our version of libc
• nimbase.h: the header file from nim repo
• setjmp.h: our setjmp header
• signal.h: ..

sorry, the repo is not well done, so i had to git init again, but its based on nimkernel code and Mero code

how

run the nim build with (change to your path)

bash build_nim.sh
qemu-system-i386 -kernel build/start.bin

TODO

• study from https://github.com/cfenollosa/os-tutorial and others

• interrupt handling: was initially copied from Mero, now I stop importing that and want to write it again

• multitasking: await/async? probably preemptive, want to have "type safe" processes instead of memory protection

• permissions? processes?

• think more shell?

• database-like filesystem api: probably for now in memory without driver

• networking: tcp stack .. complicated