When did Memory- and IO Protection Emerge (Esp. in Minis)?

On 5 May 2016 at 10:41, Mattis Lind <mattislind at gmail.com> wrote: The NORD-1 (developed 1967, sold from 1968) was a real-time 16-bit minicomputer with up to 64kw of core memory. The NORD-1 reference manual describes the memory protection system this way: "Both real-time and background programs can be run concurrently in a NORD-1 system since the real-time program can be protected against alteration. The optional features guarantees that protected areas of memory cannot be written into. The protection feature also prevents the execution of instructions that could initiate I/O transfers or change the status of the protection system." I believe this refers to, or is related to the optional virtual memory system. And more so this passage: "The NORD-1 dynamic core allocation system (paging system) is an automatic address interpretation system which allows programs to be written for 64K virtual core, with only parts of the program in physical core at a given time[..] The page table is kept in core. For each memory reference there is an automatic hardware address translation via an automatic page table reference.[..]" And it goes on to describing page fault interrupts, and privileged instructions. But although it had privileged and non-privileged instructions from the beginning, the NORD-1 did not acquire a time-sharing operating system until after mid-1971, and that was only a proof-of-concept version. It was announced in 1972 and became a product in 1973. The user- and superuser separation was implemented using the already existing instruction type separation, as mentioned. In 1973 the NORD-10 appeared as well, which fully covers the OP's requirements. The NORD-1 of 1968, or NORD-1 with VM of 1969 only partly covers it, as the time sharing operating system was not yet in place at that time.