Comment Re:Multics is not Unix.... (Score 3, Informative) 50
Unix is not Multics and that is really all you need to know about Multics
There are many interesting aspects about Multics that deserve to be heard about if not studied. To name a few: the second-dimension access system or protection rings via "ring brackets" that allowed a 'r', 'w' or 'x' access to a "segment"/file depending on the caller (user or daemon) own "running ring". Thus, a lower (higher privilege) ring program would extend its r&|x access via brackets to allow a user to enter that program (a "gate"). For instance the continuums (now forums) were usually running in ring 3, while a simple user was in 4 (the core system was in 0). Multics had also convenient and powerful ACL, accesses provided to user/group-project/login-mode. Using long names or short names for a file(segment)... Studying a bit of Multics helps to realize that most of OSes concepts were already invented ~50 years ago...