NEC ACOS-4/MVP XE

NEC announced ACOS-4/MVP XE (Multi Virtual Processor/eXtended Environment) in February 1985, and started shipping it in July 1985. 　ACOS-4/MVP XE basically inherited the architecture of ACOS-4/MVP, but the new architecture with its improvements (support for 2GB virtual memory and real memory) realized a larger scale and higher performance. It was installed in large systems of the ACOS System 1500 series, which was announced in February 1985, and in later models.