The Class II Virtual Reality was a Terran Federation technology that ultilized virtual reality.
A Class II VR was not as big and capable as the massive virtual reality computers the Terran Federation had used as homes for electronic iterations of their top R&D, military analysts, and pure researchers. It did not have the memory and the processing power to maintain two or three dozen fully aware personalities in detailed virtual environments indistinguishable from reality.
A Class II could handle no more than three or, four virtual personalities. (HFAF)