You don't have an a partition, which is what the kernel looks for by
default. Do 'boot -a' and enter wd0f for yhour root partiion, or run
disklabel and (very carefully) create an a partition with the same
data as f, and then don't use sd0f (and later delete it once a is
working).
--
Greg Troxel <gdt@ir.bbn.com>