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2.7 Scope of Work and Challenges
When converting VSE applications to OS/390 several tasks have to be performed.
The following sections describe the most important work items involved and
some of the challenges which can be encountered during the execution of these
tasks:
•
Application inventory
•
Program conversion
•
JCL conversion
•
File migration
•
Automated operations setup
•
Project management
2.7.1 Application Inventory
For a VSE to OS/390 conversion, the application inventory is nearly always
underestimated in both duration and labor.
The main application inventory activities include:
•
Determining what VSE applications must be converted to OS/390
•
Retrieving and collecting the current production version of each application
item
•
Transferring those items to the conversion input libraries on the OS/390
system
•
Verifying that the transferred inventory has no missing or unused items
One of the challenges when establishing an application inventory for a VSE to
OS/390 conversion is that the application programs must be precisely matched
with the JCL streams (for batch applications) and CICS tables (for online
applications) to be converted. This is because of the considerable blending of
application code and VSE JCL streams (see JCL conversion below). Building
these ″work units″ adds work at project start, but it becomes a significant
deliverable at project completion, when the new OS/390 application inventory
used in production is perfectly defined and centrally stored, with no missing or
unused items.
Application inventory tools are used to identify missing and unused items.
Missing items must be retrieved or recoded (if possible from a previous version),
regression tested under VSE, and used in production under VSE before being
converted to OS/390. Unused items must be eliminated or the item using them
must be added to the application inventory. The identification, collection and
transfer of the application inventory are repeated until the verification identifies
no missing or unused items.
The application inventory often leads to a re-organization of the VSE storage.
Unique centralized libraries are defined, allocated and used to store the current
production version of any application item. Obsolete or duplicate versions are
moved to non-production archive libraries.
The application inventory may last two to four months and represent 10 to 15%
of the total application conversion effort.
32 VSE to OS/390 Migration Workbook