When you edit a remote file with the System z LPEX Editor, COBOL Editor, or PL/I Editor, it looks like you are editing the file directly on the remote system, but in fact the file is downloaded to a cache within the local workspace, then saved to the remote system when editing is complete. 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). Rational® Developer for System z 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 will not make the round trip with integrity are highlighted.