Host Compatibility Option (HCO) is a set of tools that enable EBCDIC programs to work with DB2 LUW. Use these tools to offload DB2 for z/OS development and testing from a mainframe to a Windows or UNIX platform that uses IBM's DB2 LUW. You can then take these DB2 applications and use them with other Enterprise Developer features such as those in our IMS and CICS support. In addition, HCO can be used to re-host applications where the target run-time environment has changed. For example, you can use mainframe SQL syntax but replace character front ends with graphical interfaces.