ISAM/Vision migration to Oracle and COBOL re-platforming

The client Dollar Thrifty Automotive Group (formerly NYSE: DTG) is one of the largest car rental groups with presence in more than 70 countries around the world. In the US, the client has more than 800 company-owned or franchised stores. With more than 1500 International locations, they are present at almost every major airport in the world. In November 2012, it was acquired by Hertz Global Holdings in a $2.3 billion deal.

The Project

Primary objective of the project was to migrate the business critical car reservation system’s flat file structures and data into Oracle RDBMS. The conversion was accomplished in three phases: migrating the legacy ISAM database to Oracle and automated re-platforming of the application; generating additional software components for the modified target architecture; testing and QA iterations.

The size of the original application was in the magnitude of approximately 124 ISAM data files (more environments: testing; production) and ca. 700,000 lines of code in COBOL.


The project was a complex technology and organizational migration process. FreeSoft provided DTG with the following services:

  • Consulting to develop the concept and collect all details and sources of the application
  • Extensive prototype
  • ISAM data store normalization and migration
  • COBOL re-platforming
  • Unit test and integration test
  • Bug tracking and fixing
  • Training for IT Development Department

Benefits realized by DTG

  • Get rid of the ISAM files and VISION data store technology
  • Migrate and integrate data in a single enterprise Oracle data center
  • Enabling strategic redesign activities in the new environment

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