There was a delightful post about tiny (or “embedded”) versions of FreeBSD at the FreeBSD (the Unknown Giant) blog. Embedded refers to the fact that these versions can be put into tiny spaces – 16 Mb for instance – or into physically tiny spaces (toasters?) – usually both go together.
I’ve always known about PicoBSD (before it was incorporated into the FreeBSD tree even!) – and it was PicoBSD that showed me that BSD could run in 8M where Linux could not. Looks like NanoBSD picks up where PicoBSD left off. (I suppose the next generation will be FemtoBSD?).
NanoBSD is covered in an excellent article by Daniel Gerzo. There is also a nice presentation (content is rich, anyway) apparently from BSDCan 2006. Over at pean.org there is a nice concise writeup about how the writer is using NanoBSD.
There is also FreeSBIE but that’s not really an embedded operating system, just a “LiveCD”.
I simply must try one of these. You should too!
UNIX Administratosphere 
Its known that BSD takes less resources than Linux. But then there is a major factor here. Linux is a multipurpose OS. i.e. it is used on servers as well as by users at home and office, etc. Have you seen anybody using a BSD on their computer for their personal use ? No I think. 😀 But for embedded systems its good. And LOL! FemtoBSD! 😀
Explore Technology: http://www.itech7.com
Well….. I for one, have used FreeBSD as my desktop more than just once. I’ve also never seen anyone using anything but Microsoft Windows for their desktop, except perhaps the occasional MacOS X. I never did see MacOS 9 (or older) used for the desktop – and never Linux or BSD anywhere.
Quick: what’s on YOUR desktop?
Too funny. I’m running DesktopBSD on both my desktop and laptop.