"V6 Unix, portability" . "Version 6 Unix" . . "Version 6 Unix file system" . . . "Version 6 Unix#Portability" . "6th Edition" . "Version 6 Unix" . "Unix V6" . "port of Unix Version 6" . . "Unix v6" . . "6th edition of Unix" . "Sixth" . "V6" . . . . . . "between the Sixth and Seventh Editions" . . "Sixth Edition" . . "Sixth Edition UNIX" . . "Mini-UNIX" . "Sixth Edition Unix" . . . "Version 6" . . "V6 UNIX" . "UNIX Time-Sharing System v6" . .