Difference between SBCS OS/2 and DBCS OS/2

┌──────────────────────────────────────────────────────────────────────┐
│DBCS OS/2 is a common name for OS/2 NLVs that IBM provides to the Asia│
│Pacific countries requiring the DBCS character set. In general, DBCS  │
│OS/2 is released following the release-up of SBCS OS/2.               │
└──────────────────────────────────────────────────────────────────────┘

SBCS OS/2 is the base of DBCS OS/2. Therefore, DBCS OS/2 inherits many components from SBCS OS/2. In addition, the following capabilities are added to DBCS OS/2 for DBCS support:

• DBCS OS/2 supports DBCS countries' unique hardwares such as keyboards and printers. DBCS OS/2 supports US 101 keyboard and some SBCS printers as well ((**)).

• SBCS and DBCS character support

  Though DBCS OS/2 is designed for DBCS languages, it supports not only DBCS but also SBCS. Code page IDs used in DBCS OS/2 represent combinations of SBCS and DBCS code page. These code pages are called combined code page. The SBCS code pages for DBCS OS/2 include alphanumeric characters and special symbols in addition to the ones in SBCS code pages used on SBCS OS/2.

  The difference between an SBCS code page used on DBCS OS/2 and the one used on SBCS OS/2 are as follows:

  • the former reserves code areas for the first bytes of DBCS characters.

  • the former includes unique phonetic characters used in DBCS language (in case of Japanese).

  • National use characters are assigned to 5CH and 7EH.
  
  DBCS input method support

  There are too many ideographic characters to assign to key-tops. This requires DBCS-unique input mechanisms called IME (Input Method Editor). For example, Kana to Kanji conversion method is a DBCS input method for Japanese. Each DBCS NLV of OS/2 supports its own IME appropriate to the language characteristics.

  IME is transparent from an application programs. The application receives the converted data as well as usual SBCS data so far as it uses PM functions.

  
  Messages, menus, and dialog panels in Asian Languages

  Messages, dialog panels, and menus on OS/2 are translated into Asian languages for better readability for Asian users.

  
  Font

  Fonts for combined code pages are added to SBCS fonts in order to present double-byte characters. In user's DBCS OS/2 environment, more than one raster font for combined code pages are, at least, installed. This is the only one fact you can assume during application programming. Do not assume anything else on the fonts such as face names, various values of font sizes, or availability of out-line fonts.

  On DBCS OS/2 Warp, users can change the default System font to others, although they cannot do so on SBCS OS/2 V2.1.

  
  Country unique MVDM (Multiple Virtual DOS Machine).

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