From: "Ensor" <classiccmp at memory-alpha.org.uk> NetBSD is, right or wrong, noted as the run-on-anything Unix (for various values of run). That said, since the people doing a lot of the paid development are focused on highish-end embedded systems, they are less interested in slavish devotion to ancient systems. Things like GCC also have a huge impact. A few ports have recently died (anything ns32000 (e.g. pc532) due to GCC dropping support), some are discussed but never gestated (pdp10, pc-rt) and some are more moribund than others (vax, though there has been significant effort recently). The 2.x and 3.x releases have bloated to obscene proportions, like needing more than 8M of memory (;^}). You can browse the source code under "arch" and see what ports are committed. For example: http://lxr.linux.no/source/arch/. This doesn't tell the whole story, as there are at least a handful of wildcat ports that never made mainline.