The paper describes an MPP UNIX in terms of goals, implementation and initial experience in using it to port OLTP applications. Most MPP UNIX systems strive towards the goal of a conventional but massively scaled up shared memory multiprocessor. In reality this goal has never been achieved without compromising scalability or fault-tolerance. The infinity architecture achieves scalability with no single point of failure by running a separate copy of UNIX on each node. UNIX extensions make it appear as a single machine to applications. Results indicate that complex OLTP applications can be ported with ease; other applications may need to be rewritten to take advantage of the MPP UNIX.