adding disk moves ad0 to ad4

[Steve Franks]

Just curious, having read the handbook section talking about freebsd
going straight to the hardware and skipping the bios for disk
numbering, why then, if I stick a sata disk in 'sata0' on the
motherboard, does it come up as ad0, but if I add a second disk in
'sata1' or 'pata0', on the next boot, I have no ad0, but ad4 and ad6?
This seems to be the case with every mobo I've owned in the last 2
years from a variety of mfr's.  Is there a way around this?  I don't
care what it comes out as, as long as it stays put...  Since I have
the only fbsd system at work, I tend to format alot of funky drives
for people, and it gets anoying having to swap fstab's every time...

Steve