Z-series mainframe customers can order a solution that includes IBM's Integrated Facility for Linux Engine (IFL) and a subscription of Red Hat Linux Enterprise v.4 for Z-series systems. IBM and Red Hat are extending their co-marketing efforts on Red Hat Linux running on Z-series.
Implementing Linux on Z-series is done by adding an IFL to an existing mainframe system. As of the end of 2004, approximately 1,700 Z-series customers were using Linux in pilot or production. There are about 250 independent software vendors selling some 700 Linux applications on Z-series.