NEC ACOS-4/XVP PX

The ACOS-4/XVP PX (which stood for “extended multi virtual processor, parallel extended”) was an operating system intended for NEC’s mid-range and large mainframes. NEC announced the operating system in July 1994 and started shipments in October 1994. ACOS-4/XVP PX offered connectivity with open systems, realized large cost savings by adopting cutting-edge hardware technologies, and lengthened its advantage over other operating systems through various mainframe architecture revisions, such as parallel processing and cluster technologies. ACOS-4/XVP PX ran on Parallel ACOS mainframe series models, starting with the PX7500, which was announced in July 1994, and followed by the PX7800, PX7600SV, and PX7800SV.