> Why won't "a" work?  It works when I'm writing stuff like boot floppies
> (dd if=boot.fs of=/dev/fd0a)...

On large disks, the letters are used to pick a partition.
But on floppies, the letters select a disk density (because
many floppy drives can read/write multiple disk densities,
and you sometimes have to force a specific density).

I don't have a macppc handy; try "man fd" and see what it has to say.

Depending on which NetBSD port you're using, the floppy driver
may define fd0a to be the "default density as auto-detected
from the inserted media" (eg. i386), or it may define fd0a to
be the most commonly used density (sparc does this). fd0b, fd0c,
etc. are usually some fixed list of densities that cover all the
various floppy drives supported by the driver.

Todd Whitesel
toddpw @ best.com