Internationalization (i18n) on z/OS

Enhanced Definition

Internationalization (i18n) on z/OS refers to the design and implementation of mainframe applications and systems to support diverse linguistic, cultural, and regional requirements without requiring significant code changes. It enables z/OS applications to function correctly and display appropriately for users in various countries, handling different languages, character sets, date/time formats, and other locale-specific conventions.

Key Characteristics

- Character Set Support: Ability to process and display data using various character encodings, including different EBCDIC code pages (e.g., for Katakana, Cyrillic), ASCII, and multi-byte character sets like Unicode (UTF-8, UTF-16) through conversion services.
- Locale Sensitivity: Applications can adapt their behavior (e.g., date formatting, numeric separators, currency symbols, collation sequences) based on the user's or system's defined locale settings.
- National Language Support (NLS): z/OS and its subsystems (like CICS, DB2, IMS) provide features and services to manage and convert data between different national languages and character sets.
- Externalization of Language-Specific Elements: Messages, prompts, error codes, and user interface elements are often stored externally (e.g., in message catalogs or resource files) to allow for easy translation without modifying application code.
- Double-Byte Character Set (DBCS) Support: Specific mechanisms in COBOL (USAGE DISPLAY-1), PL/I, and system utilities to handle languages like Japanese, Chinese, and Korean where characters require more than one byte.

Use Cases

- Global Banking Systems: A z/OS application processing financial transactions and generating statements for customers across Europe, Asia, and North America, requiring support for multiple currencies, date formats, and languages.
- Enterprise Resource Planning (ERP): A mainframe-based ERP system used by a multi-national corporation, where employees in different countries access HR, finance, and supply chain modules, expecting localized interfaces and data presentation.
- Data Exchange with Distributed Systems: A z/OS batch job exchanging customer data with a distributed system in a different region, necessitating character set conversion (e.g., EBCDIC to UTF-8) to ensure data integrity.
- Multi-lingual Customer Support: A CICS online application for customer service agents that displays customer information and prompts in the agent's preferred language, regardless of the data's original encoding.

Related Concepts

Internationalization is deeply intertwined with Character Sets (EBCDIC, ASCII, Unicode) as it dictates how text is encoded and displayed. It relies heavily on Code Page Conversion services (e.g., iconv utility, CICS/DB2/IMS conversion tables) to translate data between different encodings. National Language Support (NLS) is a broader IBM term encompassing many of the features that enable internationalization. Subsystems like CICS, DB2, and IMS provide their own mechanisms for handling locale-specific data and character conversions, often configurable at the system or application level. z/OS UNIX System Services (USS) offers POSIX-compliant locale support, influencing how shell scripts and C/C++ programs handle international data.

Best Practices:

Design for Globalization from the Outset: Incorporate internationalization considerations early in the application design phase, rather than attempting to retrofit it later.
Utilize Unicode Internally (where feasible): For new development or major modernizations, consider processing and storing data in Unicode (e.g., UTF-8 or UTF-16) to simplify character handling across diverse languages.
Externalize All Locale-Specific Data: Store all user-facing text, messages, date/time formats, and currency symbols in external resource files or message catalogs, allowing for easy translation and maintenance.
Leverage z/OS NLS and Subsystem Features: Use the built-in character set conversion facilities of z/OS, CICS, DB2, and IMS, as they are optimized and well-integrated.
Thorough Testing with Diverse Locales: Rigorously test applications with various language and locale settings to ensure correct display, data processing, sorting, and error handling for all target regions.