For the application of (actory automation, a UNIX system with satellite processor, which can be categorized into master / slave hierarchical structure, is studied and implemented. The kernel part of UHIX is modified for the master/slavc structure, but it is designed fully compatible with the existing UNIX systems. 4 special user process is created to make easy to down load developed program from host to satellite processor with the concept of co-process. Also satellite processor can send messages and request retrain seNices from host computer. The design principles considered here art reliability, expamibility, and con-currency.