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!