In {HEAD ~ various embodiments}, user system 100 comprises {TAIL ~ a virtual system} or virtual systems executing on one or more hardware platforms 
In { HEAD ~ various embodiments } , user system 100 comprises { TAIL ~ a virtual system } or virtual systems executing on one or more hardware platforms
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH