The device driver subprogram relays {HEAD ~ the information} to the background process by calling {TAIL ~ the background program} at an entry point which is made available to the device driver at a predetermined interrupt vector location, enabling the device driver to pass the memory address of the foreground storage area, together with the size of the block of information to be communicated, to the background program 
by calling
The device driver subprogram relays { HEAD ~ the information } to the background process by calling { TAIL ~ the background program } at an entry point which is made available to the device driver at a predetermined interrupt vector location , enabling the device driver to pass the memory address of the foreground storage area , together with the size of the block of information to be communicated , to the background program
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH