| ## Analyze source changes

Identify lines in source code where non-ready dates are declared, referenced, computed, moved, read, written, sorted, whatever and where date routines are called. Look for dates stored in fields other than date fields, values other than dates stored in date fields, and calls to non-standard date routines. Source code components include compilation units and associated copybooks, batch jobs and online systems.

Basically it sounds simple enough: find and identify data names, including date transfer aliases; but this may involve tracing the impact across entire applications. Once found, determine what approach (expansion, windowing, or compression) is best for each instance and identify where you will need bridges , what kind, and whether they are temporary (to allow you to convert each side of the bridge separately) or permanent (you choose different approaches).

Specify the modifications to Source Components:

- New data elements, such as switches or fields to hold switches
- Date declarations
- Procedures, such as calling bridge programs
- Use of copybooks, rather than hardcoding
- Compilation units that are to be retrofitted with standard and/or new date routines
- Control cards and external tables (to synchronize with source changes)
- Upgrading of obsolete and incorrect date logic
- User exits for sorts dependent on unexpanded or encoded dates
- Programs and jobs to retire records that pass out of the trailing edge of sliding windows
- JCL

Visit the Technical Support Center for Date Calculation Algorithms.

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