What the OP should teach us is that there wasn't any one mainframe approach. There were many approaches, each involving many components. The process of standard

What the OP should teach us is that there wasn't any one mainframe approach. There were many approaches, each involving many components. The process of standardizing what we now know as POSIX involved pruning a lot of unnecessary pieces, but it also inevitably involved leaving out some features that might actually have been useful. Some of them (ahem ACLs) even had to be added back in later versions of POSIX. Just as we should never stop looking for new ideas that can make our lives as programmers and users easier, we should also never forget old ideas whose time might well have come back around. It has happened too many times for the possibility to be ignored except by fools.