Similar installable device drivers were employed even earlier in the UNIX/XENIX operating systems, and are also implemented in {TAIL ~ the operating system} for {HEAD ~ the Apple Macintosh computer} 
Similar installable device drivers were employed even earlier in the UNIX / XENIX operating systems , and are also implemented in { TAIL ~ the operating system } for { HEAD ~ the Apple Macintosh computer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD