What were the features of Olivetti's MOS Operating System? How Unix
like was it? Did it have a root user feature? How secure was it? Could
the system be locked down to prevent anyone from altering the system -
so each person would have access to only a predefined application and
this couldn't be by-passed as there was no user back-door (such as a
root password or ID). Any system changes once locked down would
require a rebuild of the system.

One interesting feature of the L1/MOS operating system (for the
Olivetti L1 system) was that each command name was the name of a
directory, not the name of a single binary file.  The directory
contained many files needed to run the command including at least one
file that was an executable.

A similar approach was taken by the NeXTStep operating system.