works on sparc64, this document can now use (almost) the same
procedures as i386, et al. CDROM booting instructions are cut-and-pasted
from the older sparc64/install.sgml file, which is now unlinked from
the document build.
This document is a long ways from perfect, but it's better than shipping
instructions for an installation procedure that doesn't apply anymore.
While here, add some SGML comments to help others navigate the sources.