Use the put request of the IEFSSI macro to store subsystem-specific information. The put service allows a subsystem to store a total of 8-bytes of subsystem-specific information in two non-contiguous 4-byte fields, which are identified by the SUBDATA1 and SUBDATA2 parameters. The user can store the data in either or both of the two fields on a single invocation of the put service.

A typical use of the put service is to store a pointer to a subsystem-specific control block, which the subsystem initialization routine created and made available for use by the subsystem function routines.

IBM® recommends that your subsystem create and anchor control blocks to store subsystem data, even if the stored data is small enough to fit within the two fields provided. This lets your subsystem store more information at a later time. In addition, the information stored using this service does not reside in fetch-protected storage. However, the subsystem can create its control block in a fetch-protected subpool.