mknod minors

[Sam]

OK, I understand the layout of the minor number
according to sys/disklabel.h, but what's with
the numbering scheme here?

freebsd# ls -l /dev/ad0*
crw-r-----  2 root  operator  116, 0x00010002 Nov 17  2002 /dev/ad0
crw-r-----  2 root  operator  116,   0 Nov 17  2002 /dev/ad0a
crw-r-----  2 root  operator  116,   1 Nov 17  2002 /dev/ad0b
crw-r-----  2 root  operator  116,   2 Nov 17  2002 /dev/ad0c
crw-r-----  2 root  operator  116,   3 Nov 17  2002 /dev/ad0d
crw-r-----  2 root  operator  116,   4 Nov 17  2002 /dev/ad0e
crw-r-----  2 root  operator  116,   5 Nov 17  2002 /dev/ad0f
crw-r-----  2 root  operator  116,   6 Nov 17  2002 /dev/ad0g
crw-r-----  2 root  operator  116,   7 Nov 17  2002 /dev/ad0h
crw-r-----  2 root  operator  116, 0x00020002 Nov 17  2002 /dev/ad0s1
crw-r-----  2 root  operator  116, 0x00020000 Nov 17  2002 /dev/ad0s1a
crw-r-----  2 root  operator  116, 0x00020001 Nov 17  2002 /dev/ad0s1b
crw-r-----  2 root  operator  116, 0x00020002 Nov 17  2002 /dev/ad0s1c
crw-r-----  2 root  operator  116, 0x00020003 Nov 17  2002 /dev/ad0s1d
crw-r-----  2 root  operator  116, 0x00020004 Nov 17  2002 /dev/ad0s1e
crw-r-----  2 root  operator  116, 0x00020005 Nov 17  2002 /dev/ad0s1f
crw-r-----  2 root  operator  116, 0x00020006 Nov 17  2002 /dev/ad0s1g
crw-r-----  2 root  operator  116, 0x00020007 Nov 17  2002 /dev/ad0s1h
crw-r-----  2 root  operator  116, 0x00030002 Nov 17  2002 /dev/ad0s2
crw-r-----  2 root  operator  116, 0x00040002 Nov 17  2002 /dev/ad0s3
crw-r-----  2 root  operator  116, 0x00050002 Nov 17  2002 /dev/ad0s4

Why is the whole disk slice 1, but partitions within it are
slice 0?  Why isn't the whole disk slice 0 and slice 1
is ... slice 1 (ad0s1)?  What makes ad0s2 be partition 3?

Am I reading this right?

Sam