Michael Richardson writes:
>   I have tried to build netboot.bin, which I think I load somehow from
> a DOS boot floppy (with "dosload"? where is that).

If you want to use a DOS floppy, you need to build netboot.com, not
netboot.bin.  See
<http://www.netbsd.org/Documentation/network/netboot/intro.i386.html>.

In addition to the solutions listed there, I offer an additional,
little-known one: you can load netboot from a native NetBSD boot
floppy and have it load the kernel over the network, by building
"netboot.sym" and installing it on a disklabeled floppy using
"installboot".
-- 
Andreas Gustafsson, gson@nominum.com