Indexed Files
Cannot be Unzipped on any other (non-VMS) operating system.
Notes:
RMS files are unique to VMS. They cannot be restored on any other operating system. This is true of indexed files and other types of files such as relative files.
Similarly, text files, object files, .EXE files etc. will usually get hopelessly munged if you try to UNZIP them on a non-VMS operating system, then try to transfer them back to VMS.