Now, it is probably the most focused purpose OS I have ever seen. It is an OS that the author describes as a modern day Commodore 64 OS. The entire OS is built on a C compiler and compiles the OS at boot time for the required components to boot, then JITs the rest as needed. Its actually quite fascinating, I have just watched the videos. Part of the fun of the videos for me are listening to the author describe things. He is unintentionally hilarious at times. My favorite snippet so far that absolutely cracked me up was on the video "InstallBoot(): Compiling the kernel" he was talking about setting up a RAM disk and said something like "I have 12 gig, I have nothing better to do than make ram disks...".
Anyway if anyone is interested check it out at http://www.losethos.com/
I am just having a good time listening to his videos in the background. haha. It is a very interesting project though.