Stream access is provided on some workstation platforms (currently only DDM client) to allow commands to access remote data transparently. For example, the DDM client EPM editor can be used to browse or update an z/OS file in a transparent manner. In addition, the end user on the workstation can specify TEXT on the DFMDRIVE ASSIGN or DFMDRIVE SETPARM commands to activate stream data conversion and to influence the coded character set identifier (CCSID) used to tag newly created host files. See Coded Character Set Identifiers for information on CCSID and Data Conversion for information on the DFMDRIVE ASSIGN or DFMDRIVE SETPARM commands.

Stream files created while the TEXT option is in effect will be converted to the target system code page and tagged with the value specified by HOST_CCSID. If HOST_CCSID is omitted, they will be tagged with the CCSID of the target system. See Coded Character Set Identifiers for information on supported CCSID code pages. Files for which BINARY is specified will be tagged with a CCSID of X'FFFF'.

Legacy data sets tagged with the wrong CCSID can be correctly tagged by running IDCAMS ALTER. Otherwise, they will have to be retrieved using the target server defined code page as the PC_CCSID or by using BINARY processing. For example, a text file that was stored as binary can be restored by retrieving the file from a drive assigned with the BINARY parameter and copying it to a drive with the TEXT parameter. The reverse is also true when restoring binary files that were stored as text files.

Files that are not tagged with a HOST_CCSID can be retrieved correctly by starting DFM on z/OS with the CCSID parameter in SYS1.PARMLIB(DFM00) set to the CCSID of the file(s) to be retrieved. The DFM00 CCSID value applies to all untagged files for all client access. Alternatively, a HOST_CCSID can be specified on an exception basis by using the workstation HOST_CCSID parameter on the DFMDRIVE ASSIGN/SETPARM command. In either case, TEXT must be specified to trigger stream data conversion.