Pros and cons - AWS Prescriptive Guidance
Remaining in EBCDICMigrating to ASCIIIssues with hybrid solutions

Pros and cons

During the design phase of your migration, use this guide to inform your decision of remaining with EBCDIC or migrating to ASCII. The following section provides an overview of the pros and cons of remaining in EBCDIC compared to migrating to ASCII.

Remaining in EBCDIC

Pros

  • Risk reduction by avoiding the conversion of data from EBCDIC to ASCII

  • Risk reduction by avoiding application issues where EBCDIC dependencies are missed

  • Risk reduction for external clients sending and receiving EBCDIC data (Note: There is likely to be some ETL for file type conversion but no data conversion.)

  • Risk reduction by avoiding physical EBCDIC dependencies

  • Risk reduction by reducing time required for data migration, especially for go-live deployments

  • Cost reduction by reducing time required to migrate data

  • Cost reduction by reducing time required to analyze code for EBCDIC dependencies

  • Cost reduction by reducing time required to migrate and test code

Cons

  • Increased complexity for non-COBOL downstream processing, especially applications written to use an ASCII collating sequence

  • Increased complexity for upstream and downstream interfaces that require ASCII data

Migrating to ASCII

Pros

  • Ability to use a native character set and collating sequence

  • Simplified integration with non-COBOL environments

Cons

  • Increased complexity for data exchange with mainframe environments

Issues with hybrid solutions

Programming flexibility allows for a hybrid solution. For example, you can convert the data to ASCII and run the application in ASCII, while also using an EBCDIC collating sequence. This approach can solve many problems, but can also create the following challenges:

  • Not all programming languages can selectively change the working character set and collating sequence independently. This could create a situation where a non-COBOL application can’t process the data correctly because it can’t use an EBCDIC collating sequence. For instance, data from a SQL table is returned by using an EBCDIC collating sequence, but the conditional statements in the program rely on an ASCII collating sequence.

  • Not all third-party tools and applications work in a hybrid way.

  • Programmers might not be aware of the hybrid requirements for new applications.

Ideally, your first option is to either remain in EBCDIC or migrate fully to ASCII. We recommend that you consider a hybrid solution only when the challenges of either staying in EBCDIC or migrating to ASCII cannot be overcome.