ocr: IS - AS/400 HAVING A MIDRANGE CRISIS? 1994E ERP Market hare by Operating system OS1400 Other O5 40% 16% Unix 44% SOURCE: ADVANCED MANUFACTURING RESEARCH Swing Shift. In the ERP arena, Unix surpassed OS/400 in revcnue share in 1994. AMR cites client/server support, third- party tools and better prcc/performance as reasons why.