Know the Impact Before You Change Nonstop Code

The problem

A field rename, a new validation rule, or a small enhancement is rarely small on a Nonstop system that has been running for decades. That field may cascade through undocumented copybooks. That program may be called by something nobody remembers exists. A change that looks contained can break a batch job, report, or downstream process weeks later.

AtlasHow Atlas helps

Run Atlas impact analysis on the program, file, or field you plan to change and it surfaces, from the source:

• Cross-reference matrix for program-to-file relationships
• CRUD visibility across reads, writes, updates, and deletes
• Call graph for callers and callees
• Field-level references where available
• Copybook and REDEFINES visibility
• Shared-file risk identification

NavigatorHow Navigator helps

Atlas shows what will be touched. Navigator explains why the affected logic exists. Ask Navigator to explain the current business rule before modifying the code, then regenerate documentation after the change so the system does not become next year's mystery program.

The workflow

1. Identify the program, file, or field to change.
2. Run Atlas impact analysis.
3. Review callers, files, fields, copybooks, and shared dependencies.
4. Ask Navigator to explain the existing business logic.
5. Make the change with the impact map in hand.
6. Regenerate Navigator documentation.

Example scenario

Illustrative A typical change, not a customer metric.

1. 01

   Planned change Widen a customer-ID field

   A team plans to widen a customer-ID field in a COBOL copybook on an HPE Nonstop (Tandem) system.

2. 02

   Atlas Cross-reference the copybook

   The cross-reference matrix shows the copybook is included by 40+ programs.

3. 03

   Atlas Follow the field into shared files

   The field feeds a shared Enscribe file that three batch jobs write to — including one nobody remembered was still running.

4. 04

   Navigator Ask why the width was set

   Navigator explains the existing validation rule tied to the field's current width, so the team understands why it was defined that way.

5. 05

   Outcome Re-sequenced, not broken

   With the full impact map in hand, the team updates the copybook and dependent batch jobs together, avoiding a downstream batch break.

FAQ