COBOL for AIX, V5.1:

• 64-bit application development
• Improved runtime performance and functionality
• Unicode support to develop COBOL programs that exclusively use Unicode for all application data
• Support for Extensible Markup Language to integrate COBOL with XML
• Object-oriented COBOL for interoperability with Java
• Integration of the common compiler back end from XL C, XL C/C++, and XL Fortran for AIX to give better performance
• Source conversion utility (scu) to aid in migrating COBOL source code
• Inclusion of the IBM Debugger for AIX to enable you to conveniently debug programs in 32-bit or 64-bit mode
• Integrated development environment support using IBM Rational Developer for AIX and Linux™, AIX COBOL Edition

COBOL Runtime Environment for AIX, V5.1:

• New separately orderable runtime product for execution of developed IBM COBOL applications
• Improved runtime performance and functionality

Find out more here.