NEC ACOS-4/AVP XR

NEC announced ACOS-4/AVP XR (Advanced Virtual Processor eXtended Release) in July 1988, and started shipping it in December 1988. ACOS-4/AVP XR was an operating system that inherited the design concept of ACOS-4/AVP, which was shipped in 1984, and had enhanced functions for high software productivity, and for establishing an information system by integrating distributed systems, in addition to labor-saving operability and improved ease of operation. It was installed in the small/medium systems ACOS System 3400, announced in July 1988, and its successor ACOS System 3500.