Mainframe COBOL to Java, C# & Cloud

Migrating ILE COBOL to Java / C#

ILE (ISeries) Specific issues:

Clients with ISeries machines will often have a mixture of COBOL and RPG programs. This page looks at issues in migration of COBOL programs.

The COBOL ILE Dialect is fairly close to standard IBM COBOL Implementations. The main difference is enhancements in Screen handling and access to DB400 through VSAM API.

DDS, Sub-Files and Conversational Screens

COBOL ILE allows definition of COBOL screens in DDS Sub-files. Such screens tend to be used within Conversational programs, designed for a "client-server" type deployment. The screens are accessed via READ and WRITE statements, similar to VSAM file handling. SoftwareMining converts such Conversational applications to a Application-Server architecture. DDS screen definitions translated to XML/XSLT architecture which works within a Web-Server to produce HTML screens at run-time. Although in HTML, the translated AS400 DDS screens would still be character-based, and look identical to the original screens. As a part of an application modernization project, many sites redesign the screens to benefit from a new look and feel. The translated system will allow replacement screens to be designed in JSP/ASP formats, and simply plugged into the new Java (or C#) system, without having to change any of the business-logic code.

DB400 Data Access

COBOL ILE uses standard COBOL READ and WRITE type statements to access data structures which have been assigned to DB400 (SELECT record ASSIGN TO database-record.). Ie AS400 / ISeries uses the same API as VSAM handling (keyed/ Indexed Files) for accessing DB/400 database.
SoftwareMining translates the DB400 FD's (file definitions) and record access API into Object-Relational data access classes. These classes use standard SQL for communication to the DB400 or any other SQL database. The Java translation of the COBOL ILE applications can continue running an AS/400 (iSeries) box, and access the same DB400 database. Alternatively, the database and code can be deployed on another machine (Microsoft Windows, Linux, or Solaris.

RPG on iSeries / AS400

Many AS400 and Iseries boxes contain applications written in RPG and COBOL.
SoftwareMining can offer migration of RPG to Java or C# though associated partners.
In such cases, translated RPG and COBOL applications (java or C#) will continue to communicate to offer the same functionality.

IBM ISeries/AS400. ILE COBOL to Java/C# Migration Project Phases

The Migration of COBOL applications to Java or C# involves:
  • Asset Management: Identify all the artefacts required for translation .
  • Translate to target language
  • Database and Data Migration
  • Migrate JCL
  • Create and Populate of Test Database
  • System acceptance testing
  • User Acceptance Testing
  • (Optional): Other Improvements: Screen Redesign, SOA Integration, Cloud Deployments, Coding Improvements and clean up

Comparing COBOL to translated code

Comparison of Converted code: COBOL to Java
Comparison of Converted code: COBOL to C#
COBOL to Java / C# Conversion Tool - Download Trial (Release 2023-01-09)

Related White Papers

IBM COBOL ILE (AS400 and iSeries) Migration, Modernization and Re-hosting References

IBM AS400, System I, I Series

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