The application data structure (ADS)

Application data structure (ADS) is another name for the symbolic map that is generated by the BMS macros used to define the mapping of the 3270 screen. For BMS programs, terminal data is passed between the client and the bridge in this format, giving the client application a simplified interface to the terminal data, without the need to understand 3270 data streams.

An ADS descriptor is also optionally provided, to help the client interpret the contents of the ADS. See DFHBMSUP for guidance on creating the ADSD if you have no source.

The ADS descriptor (ADSD)

The ADS descriptor allows interpretation of the BMS application data structure (the symbolic map used by your application program for the data in SEND and RECEIVE MAP requests) - without requiring your client program to include the relevant DSECT or copybook at compile time.

The ADS descriptor contains a header with general information about the map, and a field descriptor for every field that appears in the ADS, corresponding to every named field in the map definition macro. It can be located in the mapset from an offset field in DFHMAPDS.

The ADS descriptor is available only if the map load module has been reassembled (using CICS® Transaction Server for OS/390®, Version 1 Release 2 or a later release) to include the descriptor, and CICS attempts to locate the descriptor only if the BRIH-ADSDESCRIPTOR indicator is set to BRIHADSD-YES in the Link3270 message header.

DFHBMSUP

If you are unable to reassemble the mapset because you do not have the source, you can use the DFHBMSUP utility to re-create source statements from your mapset load module. See the CICS Operations and Utilities Guide for information about DFHBMSUP.

Related concepts
The Link3270 bridge mechanism
Link3270 programming considerations
BMS macro generation utility program (DFHBMSUP)
Related tasks
Using the Link3270 bridge
Writing the Link3270 client
Related reference
Link3270 message formats
The application data structure (ADS)
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