While implemented virtually rather than physically, two well-known (and very different) examples of systems that unify memory and secondary storage under a sing

While implemented virtually rather than physically, two well-known (and very different) examples of systems that unify memory and secondary storage under a single addressing scheme are Multics (1969) and the IBM System/38 (1978). Note that the present-day IBM i née AS/400 is a direct descendent of the System/38. References: https://en.wikipedia.org/wiki/Single-level_store https://en.wikipedia.org/wiki/Single-level_store https://dl.acm.org/doi/pdf/10.1145/363095.363139 https://dl.acm.org/doi/pdf/10.1145/363095.363139 http://bitsavers.org/pdf/ibm/system38/G580-0237-1_IBM_System_38_Technical_Developments_198007.pdf#page=65 http://bitsavers.org/pdf/ibm/system38/G580-0237-1_IBM_System... https://archive.org/details/insideas4000000solt/page/171/mode/1up https://archive.org/details/insideas4000000solt/page/171/mod...