DL/I and CA IDMS DLI Transparency Run-Time Environments

The DL/I Run-Time Environment
idms
The DL/I Run-Time Environment
In the DL/I run-time environment:
  • A DL/I application issues a call against a DL/I database.
  • DL/I controls the program's access to the database by using program specification blocks (PSBs) and Database Definitions (DBDs) that are stored in a run-time library.
  • Each PSB contains program communication blocks (PCBs), which define the program's database views.
  • After servicing the call, DL/I returns the status information and requested data to the program by way of the appropriate PCB. Note that in a CICS environment, DL/I also uses a user interface block (UIB) to communicate with the program.
Native DL/I Batch and CICS Environments
The following diagram shows the basic DL/I environments for both batch and CICS.
DLI_Transparency_Runtime_CICS.png
The CA IDMS DLI Transparency Environment
In CA IDMS DLI Transparency, the DL/I database is replaced by a CA IDMS/DB database. DL/I itself is replaced by CA IDMS DLI Transparency and CA IDMS/DB. The DL/I applications remain unchanged.
When a DL/I application issues a call that is addressed to the CA IDMS/DB database that contains the converted DL/I data:
  • CA IDMS DLI Transparency converts the call to the corresponding CA IDMS/DB DML call and passes it to CA IDMS/DB, which accesses the database.
  • CA IDMS/DB returns the status information and data back to CA IDMS DLI Transparency.
  • In CA IDMS DLI Transparency, the PSBs, PCBs, and DBDs are replaced by interface program specification blocks (IPSBs) and subschemas.
  • Each IPSB serves as a control block that maps the definition and structure of the DL/I database to the CA IDMS/DB database. Like the PCBs, the subschemas define the program's database views.
CA IDMS DLI Transparency Runtime Components
The following diagram shows the basic CA IDMS DLI Transparency run-time components. The remainder of this section describes how to set up the required CA IDMS DLI Transparency run-time environment for both batch and CICS.
DLI_Transparency_Runtime_Batch.png