Mainframe environments have historically been the natural choice to run the mission-critical business applications that enterprises rely on. Over time developments in processor technology have meant that Linux®, UNIX® and Windows Servers® have become able to deliver mainframe equivalent performance at a fraction of the cost. They can therefore offer more options to respond to change required by the business, while delivering the appropriate Reliability, Availability and Serviceability (RAS). This paper looks at the options available to mainframe application decision-makers who are looking to map their mainframe IT strategy to their next generation of business needs.