[rajeevk]

There are a lot of resources here in case you want to write a kernel from scratch. https://wiki.osdev.org/Main_Page

I wrote a unix-like kernel from scratch long back. It was not a fully functional unix but had a lot of components ready to the extent it would provide a command line interfaceI from which you can run commands like ls, cat etc by loading elf executables.

I would highly recommend to read this tutorial http://www.osdever.net/bkerndev/Docs/title.htm

Feel free to reach out to me (email in my profile page) if you want to discuss the topic with me.