little-os

This is to discover the awesomeness (tediousness) of developing your own OS

Why Little OS?

Well, nothing is too little compared to the priceless discovery of how Operating System works really, like you have to code for it to work, even before you can even type something into the console.

I'll use it as a teaching tool for my friends, please feel free if you want to do so

Development Environment

It hurts when you have to format your lovely Mac with Windows or any other operating system just for the sake of developing a little os. Use Vagrant instead, you can develop your os from everywhere you are, life will be easier.

Vagrant

It's everyone's favourite development environment. Head to the Vagrant download page! to download it now. We'll use Ubuntu as our development environment.

Setting up your Vagrant box

Create a new directory anywhere that you like. cd to the directory and type

vagrant init

Edit the Vagrantfile and change this line

  # Every Vagrant development environment requires a box. You can search for
  # boxes at https://vagrantcloud.com/search.
  config.vm.box = "XXX"

into

  # Every Vagrant development environment requires a box. You can search for
  # boxes at https://vagrantcloud.com/search.
  config.vm.box = "bento/ubuntu-16.04"

save the file and then type

$ vagrant up

You'll see the installation of the dev environment, or lets call it box from now on. If you have problem here or it is taking too long, just open Virtualbox app, double click on the running virtual machine named xxx_default_xxxx (name varies), and the virtual machine window will pop out. right click at the network icon at the bottom and click "Connect Network Adapter". after few second it should be up and you can quit the virtual machine and let it "Continue running on the background".

Later, when the job's done, you can SSH into the box you've just created like this

$ vagrant ssh

A little bit tuning for the Vagrant box

Make the environment directory, this will be symlinked with the Vagrant box's share path to your current vagrant dev environment on your host

mkdir environment

When you have SSH'ed into the box, you'll be able to install packages from Ubuntu just like you do with a real installed Ubuntu. And you can also read to your host machine or vice versa.

This will be useful if you want to transfer the file into the box or into your host machine. We'll always do this, so you'll want to ensure the mountpoint is working correctly:

$ sudo mount -t vboxsf vagrant environment/

Check the capacity/size

$ df -h

output:

vagrant@vagrant:~/environment$ df -h
Filesystem                    Size  Used Avail Use% Mounted on
udev                          477M     0  477M   0% /dev
tmpfs                         100M   14M   87M  14% /run
/dev/mapper/vagrant--vg-root   38G  1.3G   35G   4% /
tmpfs                         497M     0  497M   0% /sys/fs/cgroup
tmpfs                         100M     0  100M   0% /run/user/1000
vagrant                       234G  223G   12G  96% /home/vagrant/environment <<< THIS IS IT
vagrant@vagrant:~/environment$

Just need a little tuning on ~/.bashrc so you won't need to mount it everytime

$ nano ~/.bashrc

Scroll to the bottom and add

sudo mount -t vboxsf vagrant environment/
# set toolchain's path everytime
cd ~/environment/barebones-toolchain/
. ./setenv.sh
cd ..

cd to /home/vagrant/environment and do your works here

Get barebones-toolchain to get GCC cross compiler

The cross compiler contains everything we need to compile/assemble our kernel, modules and bootloaders. In the /home/vagrant/environment directory:

$ sudo git clone https://github.com/rm-hull/barebones-toolchain.git
$ cd barebones-toolchain
$ . ./setenv.sh

This has been added to your ~/.bashrc file previously so you wont need to do this everytime

Check if it works

$ i686-elf-gcc --version
i686-elf-gcc (GCC) 6.2.0
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ arm-none-eabi-gcc --version
arm-none-eabi-gcc (GCC) 6.2.0
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ mips-gcc --version
mips-gcc (GCC) 6.2.0
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Install nasm

We need nasm to build some assembly files (like common.s)

$ sudo apt install nasm

Getting little-os to Work

Now we will build Little OS into build/boot.img, a bootable disk image file powered by Grub2

Clone little-os to the environment directory

You can either clone or just download the zip file and extract it here.

In the /home/vagrant/environment directory, make the build directory (for the first time only)

$ sudo git clone https://github.com/farizluqman/little-os.git
$ cd little-os
$ sudo mkdir build
$ sudo make

When you see this message Everything is done now with success! it means the build is successful. If you have any issue building little-os then let me know by creating an issue

Boot the disk image

I used Qemu to start the disk image, you can do so by issuing this command on your host machine, in the /home/vagrant/environment directory:

!! Don't run it on your vagrant box

$ qemu-system-i386 build/disk.img

sudo make emulate

API documentations will be on the wiki page later. If you found any problem DO NOT HESITATE to create an issue