Releases a volume previously accessed by the EXCHANGE command
    MOUNT.

    Format

      DISMOUNT  device-name[:]

1  –  Parameters

 device-name[:]

    Specifies the name of the device to be dismounted. You can
    specify a physical device name or a logical name assigned to
    a physical device name. If you omit a controller designation
    or a unit number, the defaults are controller A and unit 0,
    respectively. You can also specify the name of a virtual device.

2  –  Description

    The DISMOUNT command closes all connections that EXCHANGE
    maintains to the device. This command does not affect the state
    of the operating system mount; the device remains accessible
    to OpenVMS. If you do not use the DISMOUNT command, an implicit
    DISMOUNT is automatically executed when you exit EXCHANGE.

    The DISMOUNT command is valid only with foreign devices.

3  –  Qualifiers

3.1    /MESSAGE

       /MESSAGE
       /NOMESSAGE

    Controls whether or not EXCHANGE displays a message that the
    volume was dismounted. The default is determined by the /MESSAGE
    qualifier on the EXCHANGE command when EXCHANGE was activated.

4  –  Example

  EXCHANGE> MOUNT/FOREIGN MTA0:
  EXCHANGE> COPY MTA0:AVERAGE.FOR/VOLUME_FORMAT=DOS11 *
  EXCHANGE> DISMOUNT MTA0:

      The first command in this example mounts the tape on the device
      MTA0. The second command in this example transfers a file from
      the magnetic tape to the current default directory. The last
      command releases EXCHANGE's access to the volume; however,
      the volume is still mounted on the operating system and is
      accessible to OpenVMS.