Every resource defined to CICS® by means of CEDA or DFHCSDUP is held on the CICS system definition (CSD) file, which is a VSAM data set.
The CSD file can be defined as recoverable, so that changes made by CEDA or CEDB that were incomplete when an abend occurred are backed out. CICS allows a CSD file and its resource definitions to be shared between different CICS systems. This is called compatibility mode and is intended for use when you want to create or change resource definitions on a CDS file that is shared between different releases. For more information on defining the CSD, see CICS System Definition Guide.
CICS control tables contain resource definition records for resources that cannot be defined in the CSD. The tables and their resource definitions are created by using the CICS table assembly macro instructions. You have to code assembler-language macro statements for each resource to appear in the table, assemble the complete set of macro statements, link-edit the output to produce a load module, and specify the module suffix in DFHSIT. See Defining resources in CICS control tables.