1 /LOG
/LOG /NOLOG Controls whether the DELETE command displays the file specification of each deleted file. The default is /NOLOG.
2 /SYSTEM
/SYSTEM /NOSYSTEM Controls whether the DELETE command deletes files with the file type SYS. Files with the type SYS are usually necessary for the operation of an RT-11 system. Only RT-11 volumes handle .SYS files in this manner. The default is /NOSYSTEM; the DELETE command does not delete an RT-11 file with the SYS type, whether matched by a wildcard specification or explicitly named. EXCHANGE displays a message whenever it skips a SYS file during a delete operation.
3 /VOLUME_FORMAT
/VOLUME_FORMAT=option Defines the physical format of the volume to be processed. RT-11 volumes are the only volumes on which DELETE is currently supported.