Introduction to CA IDMS VSAM Transparency › General Architecture

General Architecture

CA IDMS VSAM Transparency is a front-end to back-end design that contains dedicated modules and routines. The modules used by CA IDMS VSAM Transparency are summarized below.

• An operating system services manager interface module provides operating-system-dependent open and close services for CA IDMS VSAM Transparency files. There is one system services manager for each operating system that CA IDMS VSAM Transparency supports.
• Front-end and back-end request processing modules perform:
  • Open and close processing that is operating system independent, such as the acquisition of buffer space and BIND requests
  • All simulation of VSAM functions, after an CA IDMS VSAM Transparency file is opened or closed
• A CICS interface module (used in the CICS environment only) allows communication to occur between CICS transactions and the CA IDMS VSAM Transparency front-end module.
• Control tables define the correspondence between VSAM data structures and CA IDMS/DB data sets. There are two types of control tables in CA IDMS VSAM Transparency
  • The file management table (FMT) maps each VSAM data structure used by the application program to an CA IDMS/DB database record and set. This table is required for each VSAM data structure used, regardless of the processing environment (batch or CICS).
  • The transaction name table (TNT) maps the CICS online application transaction names to CA IDMS/DB subschema names. This table is optional for the CICS environment and is not applicable to the batch environment.

More information:

For more information on preparing control table information see Chapter 4, Preparing Control Information.

For more detailed information on CA IDMS VSAM Transparency architecture, refer to Appendix A, CA IDMS VSAM Transparency Architecture.