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Migrating RPG or COBOL Applications Written for the IBM iOS (AS 400) Platform to the Cloud

This paper is a discussion of how to migrate RPG or COBOL applications developed for the AS 400 platform to the Cloud. The approach behind this paper is to explain how to execute AS/400 iDB (DB2 400) applications in a virtual environment like VMWare to Cloud providers like Google, Amazon or Azure.


Software companies and end users developed on the IBM AS 400 platform because it offered a number of advantages – database capabilities at the machine level, stability, wide acceptance and excellent support from IBM.  Within the business community, as the industry matured, the marketplace has sought to execute their servers in a virtual environment using Cloud services from major providers like Google, Amazon or Microsoft. Starting over every time a new business requirement arises is neither practical nor justifiable. An approach is needed which enables applications to adapt to rapid business and technology changes. Many companies wish to operate their AS 400 applications in the Cloud without having to manage expensive proprietary hardware in their data centers.  They would like to access their applications without having to be concerned about managing their operating systems, database licenses or hardware requirements. They need a UI that provides graphical secure browser access to those applications that will be Cloud-provided by the large industry providers. This paper will explain how these objectives can be achieved.

With the goal of migrating and executing AS/400-based applications to an industry standard Cloud like Azure, there are certain steps to be taken.  This paper will outline the steps we would follow using the toolsets we have developed.

Step 1. Migration to an Open Platform 

In this step, we will use the Infinite I toolset to recompile AS 400 RPG or COBOL, CL and DDS source code to a new target platform like Windows or Linux. This toolset takes a complete AS 400 source library (SAVF) and recompiles those source objects in the Infinite I Deployment Environment (runtime). Once the code is recompiled, the applications can be executed using the Infinite I runtime under the target operating system. This migration does not require any rewrites of the code, and includes a complete data migration without having to manage the problems related to iDB (DB2 400).

Step 2. Migrating the Data to MS SQL or Oracle

In this step we will take the data that has been migrated to the Infinite runtime, which includes a replication of the AS 400 database and uses the Infinite I database migration toolset to populate the AS 400 data to Oracle or MS SQL. In this step, the Infinite tools will automatically interrogate the data and establish the necessary tables and columns in SQL or Oracle. Once this is done, the toolset automatically begins populating the data. Once the data has been completely migrated, the Infinite I runtime will write all future data produced from this application to Oracle or SQL.  

Step 3. Modernizing the UI and Providing Browser-based Screens

In this step, we will explain how to use the Infinite Cloud tool to automatically and dynamically create beautiful and functional graphical screens from the original character-based green ones. 

Infinite Cloud is a Java-based toolset that uses a powerful recognition engine and a screen template to read 5250, 3270, and VT100 based character screens, and render them graphically. The toolset is based on simplicity. It uses a single template so that all the screens of an AS 400-based application can be created at one time and requires very little editing.  

The use of a single template provides for a very fast implementation of the new screens and also provides for very fast screen rendering. Previous GUI products for the AS 400 environment were cumbersome, slow, and took a very long time to implement. Infinite Cloud changes that.

At the same time as the green screens are rendered graphically, they are automatically web-deployed in Java. The result is a completely web-based application that requires no client software, and can be easily and securely accessed from anywhere.

Step 4. Provision the Applications to a Cloud Provider

Once the applications are migrated, the data is migrated, and the screens are graphical and web-deployed, the applications are ready to be hosted in the Cloud.  

If Azure is the cloud platform of choice, then we recommend using Windows Enterprise Server as the operating system, Microsoft Hyper V as the virtualization environment and MS SQL as the database for the applications. If those are chosen, Microsoft can provide a complete Cloud solution that will not require the client to acquire or manage the operating system, virtualization, or database licenses. Microsoft can provide a complete platform.  

If you choose Oracle as your Cloud provider, then Oracle Enterprise Linux or Solaris would be the best Oracle-based options. Oracle can also provide their virtualization solutions and database solution as part of a complete Cloud option.

Amazon and Google can easily provision Linux or Windows-based VM’s using VMWare or any other industry standard virtualization platform. They can also provide database provisions for Oracle or MS SQL.


The purpose of this paper is to explain how AS 400 applications can be migrated to an open standard Cloud structure without having to rewrite the applications. The method we have outline here takes the applications to an open Operating System, migrates the data to an industry-standard database, makes the screens graphical and web-enabled, and then deploys the entire application to the Cloud in a matter of about 4 months and for a cost that is less than maintaining the existing IBM hardware, software, and database licenses over a 3 year period.  

In the end, the applications will be more functional, easier to use and less expensive to deploy.