Super Ya-DOS was being written from 1998 through 2004. It's a multiuser operatingsystem for x86 machines. It was written in TASM 2.0 and PowerBASIC 2.10f.
Follow these web pages as well,
http://test.nostalgy.net.ru/alien/sites/ya-dos/
http://old-dos.ru/index.php?page=files&mode=files&do=show&id=2691
FreeOS/1 is a Free, Open Source, FreeDOS based Free and Open Source Alternative OS, with open source Microsoft Windows compatibility using HXDOSExtender KernelEx,and ReactOS source code. FreeOS/1 will include new technologies and will be easy to use