IBM 3590 - Manual (Page 41)

v Stored: A Mount message is stored when a cartridge is unloading and a
Demount message is displayed.
v Displayed: A stored Mount message is displayed when the previous
Demount message is deleted. Previous Demount messages are deleted
when the accessor removes a cartridge from the loader.
v Deletion: The device removes a Mount message from the display when it
initiates a cartridge load. When the device transitions to the Ready state
(stored or displayed message), it deletes the Mount message.
Routine Messages—Demount:
v Creation: A Demount message is created when a SCSI Display Message
command is received that requests a Demount message. A Demount
message is ignored if it is received when no cartridge is loaded.
If a Demount message is received when an earlier Demount message exists
and the cartridge is loaded, the new Demount message replaces the earlier
one.
This command also deletes any general messages and deletes any previous
Demount/Mount messages.
v Deletion: A Demount message is deleted when the accessor removes a
cartridge from the loader.
Routine Messages—Combined Demount/Mount:
v Creation: A Demount/Mount message is created when a Display Message
command is received that requests a Demount/Mount message. If the
device is not loaded when the Demount/Mount message is received, the
mount portion is displayed and the Demount portion of the message is
deleted.
If the device is loaded when the Demount/Mount message is received, the
Demount portion is displayed.
If a Demount/Mount message is received when an earlier Demount/Mount
message exists, the second Demount/Mount message replaces the earlier
one.
This command also deletes any General messages and deletes any previous
Demount/Mount messages.
v Stored: If a cartridge is loaded, the mount portion of the Demount/Mount
message is stored.
v Displayed: After the demount portion of the message is deleted, the mount
portion of the message is displayed. When a cartridge is loaded, and the
drive enters the Ready state, it deletes the mount portion of a stored or
displayed message.
v Deletion: When the device transitions to the Ready state, the mount
message deletes if the device is not loaded. The message also deletes if the
Chapter 3. Drive Operator Panel and Controls 21