/sys$common/syshlp/helplib.hlb MONITOR, MONITOR, Command Qualifier Descriptions, /RECORD  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /RECORD[=file-spec]
       /NORECORD (default)

    Specifies that a binary disk file be created containing all
    collected data for the request. Note that recording is restricted
    to files on disks. No wildcard characters are allowed in the file
    specification. If you omit the file type, the default file type
    is .DAT. If you omit the file specification, output is generated
    to a file named MONITOR.DAT in the current default device and
    directory. If you specify an existing file but omit the version
    number, a new version of the file is created.