This topic provides an overview of OSA-Express for z/OS® Communications Server. An OSA is an integrated S/390® hardware feature that combines the functions of an IBM System z I/O channel with the functions of a network port to provide direct connectivity between IBM System z applications and their clients on the attached network.

For additional information about planning for and installing OSA-Express, see either the OSA-Express customer's guide and reference in your hardware library or the zEnterprise System and System z10 OSA-Express Customer's Guide and Reference.