R_OS

A simple monolothic OS for learning x86 barebones and how OSes work

Version:

1.1

Branch Info:

• The main branch contains code upto the second boot loader and will probably be renamed bootloader to be specific
• The flatmodel branch contains code where I will focus on using the flat memory model and no paging for protected mode and develop a very simple (probably single process only) kernel
• The future pagedmodel branch will contain more paged, better, and secure system to generate a multitasking OS (this is just an ambition I don't know how far will I get...)

Just because flatmodel branch uses a simple flat non paged memory doesn't mean that there will be no paging and process isolation and I will probably try to acheive those too

Sources:

• BIOS interrupts list
• OSDev Wiki
• Nanobyte OS Youtube
• Daedalus Community Youtube

Features:

• Not much, presently only bootbase.bin (first boot sector code) is finished and successfully reads and loads bootsetup.bin from memory for execution and executes it
• bootsetup.bin, is in an intermediate step and does nothing special yet

How to use?

Requirements:

• An emulator: I am using Qemu with target i386, you can use Virtual Box but you will need to write your own command to execute the binary at build/main_floppy.img(this is the OS!)
• NASM as the assembler
• A debugger: I am using bochs and would highly recommend that you do too
• And mostly knowledge about the topic to fix problems on your system

Compile and Run:

• Run make to compile the OS and then use make emu to run on Qemu, also you can run with debugger with make debug

Author:

Rouvik Maji Gmail