Physical maps produced by CICS® Transaction Server for z/OS® will also include an ADS descriptor in the output load module. This is provided to allow interpretation of the BMS Application Data Structure ( the structure used by the application program for the data in SEND and RECEIVE MAP requests), without requiring your 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).
The ADS descriptor is generated for all maps. You can use the DSECT option to select the long form of the ADS, where all fields are aligned on 4-byte boundaries. The long form of the ADS is required by the 3270 Bridge when an interface to MQSeries® is used.