The TS3500 Tape Library has I/O stations with I/O slots that allow you to import and export
up to 224 cartridges at any given time. The I/O slots are also known as import/export
elements (IEEs). Virtual I/O slots increase the quantity of available I/O slots by allowing
storage slots to appear to the host as I/O slots. These storage slots are also called virtual
import/export elements (VIEEs). With virtual I/O slots, the library automatically moves
cartridges from the I/O stations to the storage slots. In this way, the library enhances its
import and export capabilities.
The goal of virtual I/O slots is to reduce the dependencies between the system
administrator and library operator so that each performs their import and export tasks
without needing the other to perform any actions:
•
In a typical import scenario without virtual I/O slots, a library operator is needed to
stand at the physical library and fill the I/O station with cartridges; a system
administrator is needed to cause the applications to send commands for moving
cartridges out of the I/O station and into library storage slots. After the operator fills
the I/O station with cartridges, he must wait for the I/O station to be cleared before he
is able to insert additional cartridges, which means he is waiting on the system
administrator to clear the I/O station of each set of inserted cartridges. If the library is
enabled with virtual I/O slots, the operator can continuously insert cartridges into the
I/O station and the administrator does not need to issue commands to move each new
set of inserted cartridges. Instead, the library automatically moves the cartridges and
places them into virtual I/O slots until they are ready to be processed later as one
composite set of inserted cartridges.
•
In a typical export scenario without virtual I/O slots, the system administrator may
need to export a large number of cartridges from the library. However, after the I/O
station is filled, he must wait for the operator to physically remove cartridges from the
entire I/O station before he can issue another export command. This operation can be
inconvenient. If the library is enabled with virtual I/O slots, the administrator does not
have to wait to issue all export commands (up to 255 export commands can be issued
at the same time for each logical library) and the operator can remove cartridges from
the I/O stations as soon as the accessor automatically moves them from the storage
slots.
With virtual I/O slots enabled, the library has various mechanisms for selecting the best
storage slot location for each inserted cartridge, as well as the best accessor and I/O station
for each ejected cartridge. These mechanisms vary depending on the configuration of your
library.
For ejects with virtual I/O slots enabled and I/O stations in both preferred zones of a dual
accessor library, the library selects the accessor and I/O stations that are in the same
preferred zone as the physical slot of the cartridge to be ejected, but will maintain First In,
First Out (FIFO) order for each zone. For ejects with virtual I/O slots enabled and I/O
