TeachOS Kernel
==============

The TeachOS kernel for the core of the operating system.
It is implemented in assembly and C++, where the amount of assembly is kept to a minimum.
The primary design goal of the kernel is to be teachable and useful as part of the operating systems lecture track at OST.
Therefore, subsystems might not be implemented in a runtime performance optimal way but rather to be understandable and clear.

Development
-----------

Development happens primarily on Linux.
Other platforms (e.g. Windows, macOS) may allow building of the kernel as well, however at the time of this writing they are not officially supported.
To manage the toolchain and dependencies of the kernel, conan is used as a package manager.

Required Tools
~~~~~~~~~~~~~~

In orer to build the kernel, the following tools are required:

- Python 3 to run conan
- A C and C++ toolchain to build the kernel toolchain
- GRUB2 to build the bootable ISO image

Setup
~~~~~

Create an activate a Python virtual environment, for example by using the ``venv`` module:

.. code-block:: bash

    $ python -m venv .venv
    $ source .venv/bin/activate

With the virtual environment activated, install the required Python package from the ``requirements.txt`` file:

.. code-block:: bash

    $ pip install -r requirements.txt

Next, prepare the default conan profile and install the required packages (note: the example below assumes x86_64 is being targeted as the kernel's platform):

.. code-block:: bash

    $ conan profile new --detect default
    $ conan install -if .conan/install -pr:b default -pr:h .conan/profiles/x86_64-gcc -b missing 

The second command may need to be rerun in case the conan dependencies change.

Building
~~~~~~~~

With the setup performed, the kernel can now be built:

.. code-block:: bash

    $ conan build -if .conan/install .

Developing in an IDE
~~~~~~~~~~~~~~~~~~~~

This repository includes a configuration for Visual Studio Code.
In order to work on the kernel from within Visual Studio Code, activation of the conan build environment is required:

.. code-block:: bash

    $ source build/generators/conanbuild.sh

Afterward the IDE can be started from the same shell and will automatically pick up the required environment variables.