Reston, Virginia-based Systems Center Inc knew what it was doing when it bought the Net/Master network management software from its Australian developer. When it bought the product, it was confined to the IBM Corp mainframe world, but Tandem Computers Inc quickly stepped forward and invited it to do a version just announced – for its NonStops, and now from across the Pacific comes Hitachi Ltd, which wants Systems Center to adapt the software for use with the VOS3 operating system used on its M-series mainframe computers. Hitachi said the move stems from customer demand for the Net/Master software from among Japan’s largest corporations.