I guess the proper term is now VMDirectPath - take a look at
http://www.vmware.com/files/pdf/techpaper/vsp_4_vmdirectpath_host.pdf for some examples, and here (
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1016407) for a knowledge base article particular to tape drives in ESX(i) 4.x.
Good Luck