If you're into building custom OS' but not interested in doing the lowest level bits (bootloader, fiddling page table bits, worrying about the processor details

If you're into building custom OS' but not interested in doing the lowest level bits (bootloader, fiddling page table bits, worrying about the processor details, etc), using a pre-existing microkernel and building whatever you want on top of it can be interesting. I used my diploma thesis as an excuse to build a toy OS on top of a L4 (L4Ka::Pistachio) microkernel. It provides the basics, incl. IPC and VM building blocks, and a straightforward C/C++ API, and you can do the rest (there's also a number of things built on top of it that you could mix'n'match - i just implemented most of my userspace stuff because that was what I was interested in). Some links (haven't been in touch for a few years, I don't know how up to date they are): L4Ka project: http://os.ibds.kit.edu/1953.php http://os.ibds.kit.edu/1953.php OKL3 (successor to Pistachio, as far as I can tell): http://wiki.ok-labs.com/ http://wiki.ok-labs.com/ Iguana, a set of components to be (re)used on top of L4: http://www.ertos.nicta.com.au/software/kenge/iguana-project/latest// http://www.ertos.nicta.com.au/software/kenge/iguana-project/... Misc L4 resources: http://www.l4hq.org/projects/os/ http://www.l4hq.org/projects/os/ If anyone's interested, I could try to find my old code and put it on GitHub (it's a combination of MIT and GPL licenced things).