Character sets in BS2000

In BS2000, character sets are provided by the software product XHCS. By default, these include:

• 7-bit character sets such as, for example. ISO646 (international 7-bit character set, ASCII), EDF03IRV (international reference version, EBCDIC), EDF03DRV (German reference version, EBCDIC).

• 8-bit character sets such as, for example. ISO88591 (Latin Alphabet No.1, ASCII),

  EDF041

  (Latin Alphabet No.1, EBCDIC), EDF04DRV (extension of EDF03DRV) etc.

• The 3 Unicode character sets UTF16, UTF8 and UTFE.

XHCS also makes it possible to provide user-defined character sets. These character sets must be assigned all the attributes that the character sets defined by default also possess, i.e. all the property tables must be present. If this is not the case then the character set cannot be used in EDT.
In addition, EDT also requires a conversion property. It must be possible to convert all the occurring characters into UTF16.

Note

There is no guarantee that the glyphs of all Unicode characters are supported, for example the MT9750 V7 and Spool in OSD V6 do not contain the full Unicode scope but only the characters from the supported ISO 8859 variants 1,2,3,4,5,7,9,15.

In the text, the XHCS names for the names of the character sets and not the complete names, i.e. EDF041 instead of EBCDIC.DF.04-1 or UTF16 instead of UTF-16.

The UTFE character set is a BS2000-proprietary Unicode character set in which the characters are coded in byte sequences of variable length in the same way as in UTF8. The special feature of this character set is that not only all the characters from EDF03IRV but also all the relevant BS2000 control characters with the same code are coded in a single byte as previously. As a result, this character set is not just downwardly compatible with EDF03IRV, but also with the transport sequences used in communications with terminals.

The catalog entries of files and libraries in BS2000 may possess a character set specification. This specification is evaluated by the various products used in BS2000 such as OpenFT, SHOW-FILE and EDT.

Communication with a terminal is always performed in a character set. VTSU is responsible for this communication. However, VTSU makes it possible to specify a character set for each dialog step. Nevertheless, VTSU imposes certain restrictions as a function of the terminal mode. If the dialog step takes place in 7-bit mode then only EDF03IRV can be used In 8-bit mode, it is only possible to specify an EBCDIC character set which is compatible with an ISO character set variant that is supported by the terminal. If the terminal supports Unicode, then communication can take place in UTFE.

Example

The terminal is only able to depict ISO character set variant 1. In this case, EDF041 or EDF04DRV can be specified as the character set in VTSUCB. The character set ISO88591 cannot be specified since this is an ISO character set. The character set EDF042 cannot be specified since it is not compatible with ISO character set variant 1.

For more information on XHCS and character sets, see [8].