According to Wikipedia , back in the good old days, the nerds at the MIT and Bell Labs, had to figure out how 100's and 1000's of users could share the time on a multi-million dollar mainframes, so they devised the "multi user" operating system called Unix, (which was sort of cloned to mutilple variants of which OSX, Linux, BSD, etc are the current day progressions.
Its great that Android is based off a "Linux OS" however, the smart phones we use today are primarily "single user" devices, we also call them
"personal devices" The guys at MIT/Bell defined a proper 'multi user environment' with proper demarcation between users and ACLs as was the need back in the good old days, I dont believe this applies to the current day smart phone devices.
In the current scenario, of personal devices, we actually have one or may be two users but we have "multiple apps" we need a "multi-app" system with proper ACL demarcation between apps so they can share their data in a controlled manner.
Does any one know of any Android/Tizen/Linux/FirefoxOS or any other PMD OS which does a multi-user+multi-app ACL ?