> Okay, I grabbed all the archives of port-amiga going back to the end of
> November 1997.  I've not been able to find any postings about why NetBSD
> would assume that all sd?a partitions are root (/).

err, no, thats not what I tried to say. Maybe I misunderstood you.

ONLY root type RDB (0x4e4252207) partitions (and the first one... or was
it last one.. of them per driver) are translated to the NetBSD "a" partition
letter.
ONLY swap type RDB (0x4e4253201) partitions (and the first one... or was
it last one.. of them per driver) are translated to the NetBSD "b" partition
letter.

This is documented, e.g., in the Amiga specific INSTALL document.

if you have a ROOT type RDB parition on a 2nd drive, it will show up as "a",
... but its not so clear which one a loadbsd-booted netbsd kernel would 
choose as root partition.

Regards,
	-is