The NFS client supports data conversion defined by the universal character encoding standard known as the Unicode Standard on V1R2 (and later) when reading data from a remote NFS server or writing data to a remote NFS server. The Unicode Standard offers character conversion as well as basic case conversion. Within character conversion, characters are converted from one coded character set identifier (CCSID) to another. CCSID information is obtained from the cln_ccsid and srv_ccsid parameters.

Only single byte to single byte data conversion is supported. For example, if a client file has a CCSID of 437 and a server file has a CCSID of 297, data conversion will occur between USA ASCII format (CCSID 437) and French EBCDIC format (CCSID 297). Single byte to multiple byte conversion (including double byte character set (DBCS)) is not supported and will result in NFS terminating with an error message. NFS version 4 protocol (NFSv4) differs from NFSv2 and NFSv3 protocol in handling single to multiple byte conversion. Therefore, the technique-search-order specified in the convserv() attribute should consider the effects of the NFS protocol being used. SeeCreating the conversion environment for Unicode Services for further details.

The cln_ccsid, srv_ccsid, xlat , tag/notag, and convserv attributes identify whether data conversion is performed, and how data conversion is done. The cln_ccsid, srv_ccsid, xlat , tag/notag, and convserv attributes are supported by the z/OS NFS client installation parameter and TSO MOUNT command. The parameters on a TSO MOUNT command override the parameters specified as a NFS client installation parameter.

The cln_ccsid and srv_ccsid are always used to correctly display file names from a remote server. In the case of file names from a multi-byte conversion, the file names can even be viewed correctly by specifying the correct cln_ccsid, srv_ccsid and xlat(n) attribute. Note that in the case of xlat(n) there is no data conversion of a file's content - only the file names.

Sometimes, the source buffer (server file) may contain byte strings that do not represent a character in the source code page. These characters are referred to as "malformed characters" and cannot be converted to a valid target code point. These characters will be substituted during conversion processing in Unicode with the conversion table's "malformed character" substitution character.