DBCS OS/2 Additional and Unique Function

DBCS OS/2, a natural extension of SBCS OS/2, has additional functions of SBCS OS/2 to support DBCS. DBCS OS/2 adds the following supports for DBCS:

• DBCS Hardware Support

  DBCS hardware is the peripheral hardwares, for example display, printer keyboard. Following are the DBCS hardware requirements:

  • To display the complicated DBCS characters, the display device, both display adapter card and display unit, must have a high resolution.

  • If possible, the display device should provide a built-in DBCS font image data to enhance the performance in displaying the DBCS characters.

  • The DBCS printer supports the DBCS printer data stream and some have built in DBCS font data.

  • The DBCS characters require more keys to allow the user in data input task. The DBCS keyboards are designed to satisfy this requirement.
  The SBCS OS/2 can support the DBCS hardware with only the SBCS capability. The DBCS OS/2 supports the DBCS hardware with the DBCS capability. The DBCS OS/2 from 2.1 also supports various types of DBCS keyboards of OEM in each country as well as the 101 keyboard of PS/2 which is not originally designed for the DBCS personal system.

Data Type Support

The character data type is enhanced to support mixed strings and DBCS strings in Database Manager. The single-line entry-field control of Presentation Manager is enhanced to filter user input to an SBCS string, a mixed string or a DBCS string. Details of the support in each OS/2 component are explained in the relevant sections of Database ,Presentation. The data type support is common to all the DBCS countries.

DBCS Support File System

The file system is enhanced to allow the file name to include DBCS characters. However the DBCS alphanumeric characters are treated as a two-byte data, and do not have the limitation of using the invalid symbols or uppercasing handling for them when use them in a file name.

Note: If a file is created on a DBCS environment with a name including DBCS characters, then it can not be recognized on an SBCS environment.

Note: You cannot use DBCS characters as the file name punctuation characters such as period separating the file name from the extension, the path delimiter (backslash) in the path name and the colon in the drive specifier. (See also SBCS PC Code for Each DBCS Language regarding the path delimiter.)

DBCS Font Management

The DBCS OS/2 provides DBCS font to the combined code page OS/2 screen section. The system default font of the DBCS PM is also a DBCS font.

DBCS OS/2 additionally supports DBCS OS/2-unique API to load combined code page fonts; and each country's edition supports its unique font resources.

Note: DBCS OS/2 supports the font loading API calls that SBCS OS/2 does, such as GpiLoadFonts. However, these APIs do not support all the combined code page fonts. The combined code page raster fonts are supported by the font drivers. DBCS OS/2 provides the DBCS unique load and unload APIs for the font drivers. When a font driver is loaded, the combined code page fonts that are provided by this font driver will become available.

Country Code and Code Page Support Each DBCS OS/2 NLV supports only one country code, and 3 to 4 code pages. The primary code page must be a combined code page. The OS/2 system commands or utilities check the environment code page to provide appropriate messages and data format. For example, the DIR commend will display Japanese message in code page 932 but display English message in code page 437; the SYSTEM EDITOR will display the Japanese editor window when it is executed from a 932 OS/2 command prompt but display the English editor window when it is executed from a 437 OS/2 command prompt.

DBCS countries' code page support for devices (such as display, keyboard and printer) is added in DBCS OS/2.

DBCS Keyboard and Input Method Support

The keyboard is enhanced to allow the user to input the DBCS characters from the keyboard input device.

As there are too many DBCS characters to assign each one to a key-top, a special input method is required and it is called DBCS input method. Each country's edition of DBCS OS/2 provides a DBCS input method specifically to that country as a standard feature. (For example, Japanese OS/2 supports Kana to Kanji Conversion Method.) Usually applications do not take care of the conversion process. This is done within DBCS OS/2 and is not recognized by applications.

DBCS Text Format Support

DBCS OS/2 provides text punctuation function support such as the word wrap and line breaking handling. The WinDrawText of SBCS OS/2 does not support text formatting of Asian countries, but DBCS OS/2 does.

Translated Messages and Panels

Messages and panels of each country's edition of DBCS OS/2 are translated into its own language.