This is the osFree OS/2 personality, the set of services implementing the OS/2 API. It currently has implementations for L4Env and Genode. You should checkout osFree sources first: # mkdir osfree # cd osfree # git clone https://github.com/osfree-project/osfree/ . # git submodule update --init create a symlink for osfree/OS2/Server (under the "os3" name): # cd .. # ln -s osfree/OS2/Server os3 Then build the corresponding environment and OS/2 personality sources, based on it: For L4Env build, look into ./platform/l4env (some functionality is working). For L4Re build, look into ./platform/l4re (only a stub for now). For Genode build, look into ./platform/genode (incomplete, yet). Look into README file in the corresponding environment specific directory for further instructions.