Built on top of the RMAPI is the Data Service Development Library (DSDL), which provides a higher-level integrated framework while retaining the underlying method-callback model of the RGM. The DSDL brings together various facilities for data-service development, including:
libscha.so—the low-level resource management APIs
hatimerun—a facility for running programs under a timeout (see hatimerun(1M).
For the majority of applications, the DSDL provides most or all of the functionality you need to build a data service. Note, however, that the DSDL does not replace the low-level API but encapsulates and extends it. In fact, many DSDL functions call the libscha.so functions. Likewise you can directly call libscha.so functions while using the DSDL to code the bulk of your data service. The libdsdev.so library contains the DSDL functions.
See Chapter 6, Data Service Development Library (DSDL) and the scha_calls(3HA) man page for more information about the DSDL.