Preserving round-trip integrity of MVS files

Round-trip integrity ensures that characters converted from one encoding (code page) to another and then back to their original encoding remain unchanged.

Supported Editors:
  • COBOL Editor
  • JCL Editor
  • PL/I Editor
  • z Systems® LPEX Editor. In this editor, the operation cannot be undone.

When you edit a remote file, it looks like you are editing the file directly on the remote system. In fact, the file is downloaded to a cache in the local workspace, then saved to the remote system when the editor session ends. This process of downloading to the workstation and then uploading to the remote system involves converting the file contents between the remote EBCDIC-based encoding (for example, IBM®-037) and the local ASCII- or Unicode-based encoding (for example, Cp1252 or UTF-8). Developer for z/OS® uses code page mappings to determine the remote and local encodings, as described in Remote to local file mapping.

Certain characters do not translate precisely from one code page to another and then back again, depending on the code pages involved. To ensure round-trip integrity, the editors open remote files in browse mode so that you cannot corrupt the file by saving it back to the remote file system. In addition, the characters that cannot make the round trip with integrity are highlighted.

Note: Setting the workstation code page to UTF-8 can reduce the number of characters that do not transfer correctly. Local compilers, however, often do not accept source files in UTF-8.