References:
The Provably Secure Operating System (PSOS) project began in 1973 and continued until 1983. The 1980 PSOS final report includes the system architecture and many of the basic hardware and operating system layers, plus some illustrative applications (all formal specified in the SPECIAL language of HDM, the Hierarchical Development Methodology). The Feiertag/Neumann paper summarizing the architecture as of 1979 is available in a retyped, more or less correct, hand-edited pdf form.
References: reference More
If you could revise
the fundmental principles of
computer system design
to improve security...
... what would you change?