VMS Help DEALLOCATE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Makes an allocated device available to other processes (but
    does not deassign any logical name associated with the device).
    DEALLOCATE does not deallocate devices that are in use.

    Format

      DEALLOCATE  device-name[:]

1 - Parameter

 device-name[:]

    Name of the device to be deallocated. The device name can be a
    physical device name or a logical name that is not in use. On a
    physical device name, the controller defaults to A and the unit
    to 0. This parameter is incompatible with the /ALL qualifier.

2 - Qualifier

 2.1 - /ALL

    Deallocates all devices currently allocated by your process that
    are not in use. This qualifier is incompatible with the device-
    name parameter.

3 - Examples

    1.$ DEALLOCATE  DMB1:

      In this example, the DEALLOCATE command deallocates unit 1 of
      the RK06/RK07 devices on controller B.

    2.$ ALLOCATE   MT:   TAPE
      %DCL-I-ALLOC, _MTB1:  allocated
         .
         .
         .
      $ DEALLOCATE  TAPE:

      In this example, the ALLOCATE command requests that any
      magnetic tape drive be allocated and assigns the logical
      name TAPE to the device. The response to the ALLOCATE command
      indicates the successful allocation of the device MTB1. The
      DEALLOCATE command specifies the logical name TAPE to release
      the tape drive.

    3.$ DEALLOCATE/ALL

      In this example, the DEALLOCATE command deallocates all devices
      that are currently allocated.