The concept of shared data tables is simple; it exploits the fact that it is more efficient:
SDT completely replaces and extends the basic data table services that were originally provided.1
Under SDT, all files that are defined as data tables can potentially be shared using cross-memory services; no changes are required to the file definitions for existing data tables.
The use of cross-memory services is one of the major enhancements to data table services that is included in the SDT facility. This enhancement improves the performance of applications that currently use function shipping and makes file sharing feasible for applications that cannot accept the performance overhead of function shipping.
The other major enhancement is that nearly all read requests are supported for use with data tables. This enhancement extends the use of data tables to applications that include:
See What you need to know to understand this book for the definition of application programming terms used in this book.