coupling first and second processors in parallel wherein {HEAD ~ said first and second processors} include means for selectively disabling {TAIL ~ the outputs} thereof 
coupling first and second processors in parallel wherein { HEAD ~ said first and second processors } include means for selectively disabling { TAIL ~ the outputs } thereof
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH