T 3.66 Incorrect character conversion on the use of z/OS

EBCDIC (Extended Binary Coded Decimals Interchange Code) and ASCII (American Standard Code for Information Interchange) are coding tables that define which letters, numbers and other characters are represented with the aid of 8 and/or 7 bits.

z/OS systems use EBCDIC code. Only HFS and zFS file systems (Hierarchical File Systems) used with USS (Unix System Services) permit data to be saved in both ASCII and EBCDIC. On the exchange of data between z/OS systems and systems using ASCII code (e.g. also from USS to MVS), there is a risk that information could be corrupted if incorrect translation tables (code page translation) are used. A particularly frequent problem here is the translation of special characters.

Examples:

• In a company, data were transmitted between various OS/390 and z/OS systems using the FTP protocol without problems over an extended period of time. The same FTP job was used for an additional Unix system and the EBCDIC-ASCII translation performed using the default table. First, the transfer went without problems; however, on the further processing of the data records in the Unix system, it was found that, in some cases, the German umlaut and special characters had not been translated correctly. Only after the preparation of a special translation table used only for this transfer was the error eliminated.

• On the transmission of a file using the FTP protocol from one z/OS operating system to a Unix operating system, the Binary option was used. It was not possible to further process the data on the target system, as the Binary option suppresses the conversion from EBCDIC to ASCII.