Using the communications storage manager (CSM) function, authorized host applications can share data with other CSM users without having to physically move the data. A CSM user can be any system-authorized application program or product. Users of CSM obtain and return storage in the form of CSM buffer pools by using the IVTCSM macroinstruction.

VTAM® uses CSM to perform channel I/O over a HPDT MPC connection and to provide the high-performance data transfer (HPDT) function for host LU 6.2 applications. (HPDT MPC connections are explained in Multipath channel connections.) Host LU 6.2 applications use the IVTCSM and APPCCMD macroinstructions to reduce the use of system resources for large data transfers. For more information about the HPDT function, see High-performance data transfer (HPDT).

The application programming interface for CSM is described in z/OS Communications Server: CSM Guide.

For information about how to install, configure, monitor, and diagnose CSM storage, see Communications storage manager.