Learn more about the key features of IBM DL/I VSE

Allocation of DL/I resources above 16 MB

When running in a CICS/DLI online environment, the following DL/I resources can be allocated above the 16 MB line of storage: PSBs and their transaction working copies, HD data buffers, most of the DL/I action modules and DL/I user exit routines (excluding randomizers). Moving HD buffers above the 16 MB line will also allow for keeping more data in storage with possibly faster access to the DL/I data.

DL/I GETVIS storage in separate subpools

GETVIS storage allocated for different types of DL/I resources is assigned to different sub-pools. This includes: PSBs loaded during CICS/DLI initialization, PSB working copies for the single transactions, buffer pool for HD databases, action modules and user exit routines and queuing elements of the Program Isolation function. The amount of storage that is held by the different subpools can be viewed with their respective subpool-IDs.

More than one Multiple Partition Support System (MPS)

The DL/I Master Partition Controller for the DL/I MPS function can be activated in more than one CICS/DLI online partition at the same time. This way an MPS batch job can connect to any active CICS/DLI online system and process databases defined there (one connection per job step). The option to dynamically select regular batch (DLZRRC00) or MPS batch (DLZMPI00) execution via the DLZCTRL program has been adapted to the Multiple MPS environment.

More than four GB for HD databases

The data component of DL/I HD (HDAM/HIDAM) databases can be allocated on more than one VSAM ESDS dataset. Up to five datasets can be defined, increasing the maximum database size to 20 GB (5 times 4 GB). The enhancement is transparent to user applications. The split into multiple datasets will be realized through an updated DBD definition and a reorganization or new initial load of the database.

Support of CICS storage protection

When CICS storage protection is active, DL/I control blocks and data buffers are allocated in storage protected with partition (CICS) key. This prevents online applications (provided they run in user-key) from inadvertently overwriting DL/I storage – affecting the availability or integrity of the CICS/DLI online system. To benefit from this protection, CICS/DLI online applications should be defined with user-key. DL/I internally switches to partition-key when processing a DL/I request.

Conditional SVA loading disabled

The SVA= parameter is not supported anymore. Starting with z/VSE 4.3, the CICS coexistence environment is not supported and DL/I VSE 1.12 is the only DL/I release that can be used. Until z/VSE 4.2 it was possible to run CICS/VSE 2.3 and DL/I DOS/VS 1.10 on the same VSE system, in a coexistence environment together with CICS Transaction Server for VSE/ESA and DL/I VSE 1.11.