In a move that completes its metamorphosis from general purpose Unix supplier to image processing system specialist, Plexus Computers Inc, San Jose has sold its Unix system service and support operations to Motorola Inc’s Computer Group for an undisclosed sum. Under terms of the agreement, Motorola will assume responsibility for supporting the Plexus user base in North America and Europe, estimated to comprise some 2,500 Unix systems worldwide. Plexus will focus its field resources on the image processing market it said, adding that the XDP systems busin ess now accounts for the majority of the company’s revenues. Plexus changed strategic direction in 1987 to market systems designed to man age multiple types of data, such as image, text and alphanumeric data. It’s most recent sale was a $10m multi-site installation at the Pru dential Insurance Co of America.