ODS - 1 is the flat file system used by the RSX - 11 OS , supported by older VMS systems for RSX compatibility .
ODS - 1 never used to support VMS itself ; it has been largely superseded by ODS - 2 and ODS - 5 .
ODS - 1 is the flat file system used by the RSX - 11 OS , supported by older VMS systems for RSX compatibility , but never used to support VMS itself ; it has been largely superseded by ODS - 2 and ODS - 5 .