Why is swap device reported with wrong name?

[Geoffrey T. Falk]

I just added an old drive to use as a swap disk on ad1 on my 4.8-STABLE
system. Why is the name reported as "/dev/rad1s1b"? /dev has both
devices.


bork% swapinfo
Device          1K-blocks     Used    Avail Capacity  Type
/dev/ad0s1b        409472     5388   404084     1%    Interleaved
/dev/rad1s1b       130944     5304   125640     4%    Interleaved
Total              540416    10692   529724     2%


/etc/fstab has:

# Device                Mountpoint      FStype  Options         Dump    Pass#
/dev/ad0s1b             none            swap    sw              0       0
/dev/ad1s1b             none            swap    sw              0       0


Thanks for any insight.
Geoffrey