Since upgrading to 8.1-RC1 and adding ATA_CAM and device ahci to my kernel, for the first time I've experienced a successfull hotplug of an external SATA disk on my FreeBSD machine. The Asus P5B motherboard I've got has an external SATA connector on its backplane that I've never been able to make work. From what I can tell, it's connected up to the JMicron JMB363 controller on the board, which ostensibly means that I could use a port multiplier, if I had one (unfortunately, the ICH8 controllers don't support port multipliers, at least so says the kernel).