DP4 allows system code to be developed and maintained separately from database applications. System code can be used for the following purposes:
Supporting a device using a special driver or OSDI
Handling a connection to an auxiliary database or file system
Managing messages between your DP4 system and a host system
Adding routines written in C to a QA Build program
You can use system code to add flexibility and intelligence to an application, without adding to the complexity of an application program.