> Has anyone looked at how the mach microkernel boots on the Alphas?  Does
> it only work the the OSF palcode?

Mach3 (mk83a) from CMU does boot on older (TurboChannel) Alphas with
some minor fixes.  Non-freely-available Mach microkernels from OSF
very likely work better (and on all Alpha models), I haven't tried
those.

Mach3 on the Alpha uses the VMS palcodes and relies heavily on them.
It also overrides the "switch-to-OSF palcodes" call in osfboot
(normally osfboot is used to switch palcodes).  There are lots of
palcode calls in the VMS palcodes that don't exist in any of the other
ones.

Luckily, the OSF palcode for invoking a system call just "happens to"
map to a VMS palcode that does the same thing (although it has a
different name), so emulating OSF/1 (Digital UNIX) and NetBSD is
possible.