Ugh, I'm not even an apple user and I can
almost assure you Apple, Darwin, has always had shadow copy features (aka snapshots or some other name). Remember, Darwin is based on Mach, which is, in turn, based on BSD. Newer Apple systems also include much of FreeBSD.
http://www.freebsd.org/cgi/man.cgi?query=GEOMGEOM is an interface to do stuff like snapshots, RAID, and etc...
If you sit down at an Apple machine and open up a terminal, you will essentially see, feel and breathe a BSD system below its very beautiful interface.