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

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

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 diagram below shows the basic DL/I environments for both batch and CICS.

Figure 51. Native DL/I batch and CICS environments

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 diagram below 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.

Figure 52. CA IDMS DLI Transparency basic runtime components