Breaking news Sartoris has gone 1.0!
Asgard is a multi-server operating system based on Sartoris.
The easiest way to run Sartoris+Asgard is to download the Bochs environment. You will need at least Bochs 2.2.1. If you would rather compile everything from source, grab both tarballs from the links above (or get the latest CVS snapshots) and untar both trees to the same directory. Then compile Sartoris (just use plain good old GNU make) followed by Asgard. This shuld leave a bootable binary image in asgard/bin and a ready-to-use Bochs environment in asgard/bochs. You need gcc, binutils and make from GNU, the ones found in any current Linux distribution should do fine. FreeBSD (using gmake, not the native one) used to work fine as well, and Nicolás had a way to compile everything on Windows, but was sort of horribly messy. You can ask him about it, or anything else for that matter, through the developers mailing list