The SYS_LOADABLE ADD command adds an entry to the system images file SYS$UPDATE:VMS$SYSTEM_IMAGES.IDX. You can then process this file using the command procedure SYS$UPDATE:VMS$SYSTEM_ IMAGES.COM. Processing the file with VMS$SYSTEM_IMAGES.COM generates a new system images data file that the system uses when it boots. If the file SYS$UPDATE:VMS$SYSTEM_IMAGES.IDX does not exist, the SYS_LOADABLE ADD command creates a new one.