I think you're thinking QNX and not BeOS (BeOS
requires at least 32MB
and
200MB disk space). I know QNX can be squeezed down to
that (or at least
could at one point, not sure if it still will fit on a floppy).
Thats it. QNX even has a demo with a browser that fits on floppy.
There is also the linux kernal project, I have the LRP (router) on
a single floppy. Though for smallness there is CPM-86 and DOS.
Allison