Arix Corp, San Jose is not letting the painful rescheduling of orders from its largest customer, Unisys Corp, put it off its stride: in an effort to build itself a complementary business, the builder of multiprocessor Unix supermicros has opened an image management systems division in Washington, DC. The new company is called Imix, and it is planning to introduce its first hardware and software products for image storage, retrieval and manipulation at the back end of 1989.