NEC ACOS-6/MVX II

NEC announced ACOS-6/MVX II (Multiple Virtual eXtended II) in November 1988, and started shipping it in March 1989. 　ACOS-6/MVX II was an operating system for large to ultra-large machines that achieved enhanced functionality, expandability and reliability while maintaining upper compatibility with the operating systems ACOS-6 and ACOS-6/MVX for large machines, which were shipped earlier. It enabled establishment of a larger-scale, higher-performance relational database system and a more available hot-standby fault-tolerant system than ACOS-6/MVX. ACOS-6/MVX II was installed as an upper compatible successor OS to systems 830, 850, 930, 1000 and 2000, which operated with ACOS-6/MVX.