Considerations for Languages

In addition to DBCS support, you must take certain language related considerations into account. Another IBM document, National Language Information and Design Guide covers such considerations as well as NLS considerations common to SBCS and DBCS, such as PII (or MRI) isolation from executable code. This document is available through the normal manual order process. The order numbers are:

• SE09-8001 Volume 1: Designing Enabled Products, Rules/Guidelines

• SE09-8002 Volume 2: National Language Support Reference Manual

• SE09-8003 Volume 3: Arabic Script Languages

• SE09-8004 Volume 4: Hebrew

The following explains some considerations on multilingual support which may not be covered in the document above:

• Multi-users

  If your product sends messages to several destinations, it is desired that your product dynamically switch the messages, for example, between Japanese and English since) not necessarily all of the destinations are PS/55 (some may be PS/2) and not all of the destination users are Japanese.

                         IBM PS/55
                         ┌───────┐
                         │SERVER │  Multilingual
                         │STATION│  Message/Panel Support
                         └───┬───┘  for Downstream Station
                             │
              ┌──────────────┴────────────────────┐
  Workstation │                                   │Workstation
     ┌─────┐  │                                   │  ┌─────┐
     │IBM  │  │                                   │  │IBM  │
     │PS/2 ├──┤                                   ├──┤PS/55│
     └─────┘  │                                   │  └─────┘
     English  │                                   │  DBCS
     Message  │                                   │  Message
              └───┬──────────────────────┬────────┘
               ┌──┴──┐                ┌──┴──┐
               │IBM  │                │IBM  │
               │PS/55│                │PS/2 │
               └─────┘                └─────┘
               DBCS                   English
               Message                Message
  Multi-users environment
  

• Code Page Switch and PII Switch

  DBCS OS/2 also supports code page 437 and 850 as the secondary code page. Some products are desired to support the SBCS code pages on DBCS OS/2, for example, PS/55 users may want to edit a file that should be sent to PS/2 users (or English speaking people) and use an editor under an SBCS code page. If the user switches the current code page to an SBCS code page, PII (messages and panels) translated to DBCS languages is displayed as garbage. Such products should support PII switching to avoid that. To support PII switching:

  • Prepare two sets of PII for each language; one is translated to a DBCS language (default) and the other remains in English,

  • At the initialization of the program, check the current code page,

  • If the current code page is an SBCS one, switch PII to English.

    Note: You may allow the user to switch to English PII when the current code page is a DBCS since:

    • the SBCS characters from range 20H to 7DH (except 5CH) in combined code pages are the same as those in 437 or 850 and English PII can be displayed with DBCS code pages, without becoming garbage.

    • some English speaking people (such as American developers of international products supporting DBCS) need to use DBCS capability.
    4.
    In case your application program runs on a code page which is not supported by it, it should provide the English error message as the default to be used in this error case.
    DBCS OS/2 itself supports PII switching; system messages, the system menu and PII of the system editor are switched together with the current code page.

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