SDF is delivered together with syntax files containing:
information on the syntax of commands and statements
information on how these commands are implemented in BS2000, e.g.
the names of the system modules which handle command execution
the conventions for parameter transfer to the executive system modules
information on privileges that the calling user must possess
general and command-specific conventions for dialog guidance
explanatory texts relating to the commands and their operands (help texts).
SDF extracts the information it requires for processing a command input from the activated syntax files.
Similarly, SDF supports the input of statements to any programs which are defined in a syntax file, e.g. to SDF-A or SDF-U.
The software product SDF-A (System Dialog Facility-Administration) and the utility routine SDF-U (System Dialog Facility-Utility) can be used to process syntax files.
Syntax files can be merged by means of the utility routine SDF-I.
There are three types of syntax file:
system syntax file
group syntax file
user syntax file.
It is possible to activate more than one syntax file for a given task: one basic system syntax file and several subsystem syntax files. In addition, one group and one or more user syntax files may be activated for a given task. For this eventuality, there is a fixed file hierarchy defining how SDF handles a number of syntax files.