A successful conversion from DL/I to Adabas presupposes a clear knowledge of the existing system (which DL/I databases exist, which applications access these databases in batch or online mode etc.) and well defined goals. This section outlines some aspects of the conversion process which might be worth considering prior to the conversion.
This document covers the following topics:
The first task in the conversion process is obviously a stocktaking of the existing DL/I databases, PSBs and applications in your environment. The result of this stocktaking process should be a list of DL/I DBDs, PSBs and application programs and should also show which applications use which PSBs and, in turn, which DBDs are referenced by the individual PSBs.
You should be aware that the ADL conversion utilities require the DL/I DBDs and PSBs to be available in source form. The above mentioned list thus might also contain the information where the corresponding DBD or PSB source code can be found.
During the conversion process, you might wish to convert DL/I databases in groups according to their interrelation with applications. On a first level, this could simply be based on whether two DBDs are referenced in one and the same PSB. Also, an online application might schedule several PSBs, which in turn might reference several DBDs. These DBDs could then be considered to be interrelated via this application.
Despite the fact the ADL CALLDLI Interface allows applications to run in mixed mode (accessing original DL/I databases and ADL files concurrently), it might turn out that the conversion process can be simplified and the testing phase shortened if databases related to one and the same application are converted at the same time.
Note that any two physical DBDs which are interrelated by a DL/I logical relationship must be converted together.
When large databases are to be converted, it is important to consider the space that will be required for these databases after the conversion. You should be aware that, during the conversion process, the space owned by the database is needed twice, namely in the DL/I system as well as in the Adabas system.
It is recommended that the Adabas database administrator is consulted prior to the conversion process, to determine the space needed for ADL files.
Similarly, the time required for the unload and load batch jobs during the conversion of a DL/I database is comparable to the time needed, for example, for a reorganization of the DL/I database.
