$CREATE/MAILBOX/PERMANENT/MESSAGE_SIZE=512/LOG MY_MAILBOX
  %CREATE-I-CREATED, MBA38: created
  $SHOW DEVICE MBA38/FULL
  Device MBA38:, device type local memory mailbox, is online,
      record-oriented device, shareable, mailbox device.

   Error count              0  Operations completed                0
   Owner process           ""  Owner UIC                    [SYSTEM]
   Owner process ID  00000000  Dev Prot  S:RWPL,O:RWPL,G:RWPL,W:RWPL
   Reference count          0  Default buffer size               512

      In this example, a permanent mailbox is created with the
      logical name MY_MAILBOX. The SHOW DEVICE command displays the
      full characteristics of the mailbox.