The processing attributes that specify whether or not data conversion occurs between ASCII and EBCDIC formats may have the most influence on the performance of z/OS NFS. The binary attribute, which specifies no data conversion, is the most efficient manner in which to access data by way of z/OS NFS. However, data conversion may be a requirement, particularly when data is shared with z/OS users or applications. Under such circumstances the text processing attribute would be specified instead of the binary processing attribute. The actual impact associated with data conversion will depend on the data to be converted.

In text processing mode for MVS data sets, end-of-line (EOL) terminators are inserted into the data at the end of each record to preserve the record format when data is viewed from the z/OS NFS client. However, text mode processing invokes an implicit ASCII to EBCDIC translation, which is not needed for a z/OS to z/OS mount. If, during text mode processing, this implicit data conversion (ASCII to or from EBCDIC translation with UNICODE and XLAT) is disabled using the srv_ccsid(1047) and cln_ccsid(1047) processing attributes on the mount command then the EOL terminators are converted (including EOL terminators such as LF, CR, NL) to an internal representation of the MVS data on the z/OS NFS server. The z/OS NFS server will use the EOL internal representation as record boundaries when writing to a data set. During reading of data from an MVS data set, the insertion of EOL terminators (in the internal representation on the z/OS NFS server) is used to create record boundaries. The data with EOL terminators are then converted to the external representation before replying to a client.