Example

 $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.