from Daniel Robbins of Gentoo Technologies, Inc.:

	The "stage1" tarball is what we used to call a "build
	tarball".  It is a chrootable image that you can use to
	build Gentoo Linux completely from scratch.  It requires a
	bootstrap and an "emerge system" to convert it to a bootable
	Gentoo Linux system, and it will run on any PC (i486 or
	greater).

WWW:  http://www.gentoo.org/