HP A3716A DDS-3 Autoloader User's Manual - 3716-96001

Using Your Autoloader
Autoloader Modes of Operation
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cartridge 1 so that it can restore the file. As a user, you may not even be aware
that the cartridge has been changed.
Use of random mode requires two things:
n The host computer must be able to support multiple LUNs (Logical Unit
Numbers), by which it identifies different devices at a single SCSI address,
so that it can send commands separately to the changer mechanism and the
DAT drive in the autoloader.
n The software must be able to provide the necessary functionality.
Stacker Mode
In stacker mode (also known as sequential mode), the autoloader simply uses
the cartridges sequentially from the magazine. When one cartridge is unloaded
(following a SCSI UNLOAD command), the autoloader automatically loads the
cartridge from the next highest numbered magazine slot.
You can select the first cartridge you want the autoloader to load by using the
Select and Load Cartridge buttons on the front panel.
Changing Modes
Figure 3.5 shows how the autoloader moves between four states:
n Empty, when there is no magazine in the autoloader.
n Neutral, when a magazine has been inserted but no cartridges have been
moved to the DAT drive and no commands have been received to move a
cartridge. It is while the autoloader is in the neutral state that you can select
a cartridge for loading using the Select button.
n Stacker mode
n Random mode
The diagram is simplified. In particular, it does not show how the situation is
altered if the host computer cannot address multiple LUNs at a single SCSI
address.
Figure 3.5 Autoloader modes of operation