a
tape robot or
tape library is a device that automatically loads a
tape drive with
tapes.
Usually found close to really
big iron, it is generally used either to automate
backups or to serve
data from *really* large collections: an example would be historic sequences of
satellite images or
seismic data.
Since it is very expensive to put this stuff on primary storage (read: disks), and since having to phone the tape dude to ask him to mount tape #13324-A7 is slow and expensive, the tape robot was born.
They go all the way from little 7 tapes things to huge terrifying things that look like high-tech gazebos with things moving on the inside. And laser red lights, reading the optical codes printed on the back of the tapes (remember, belt AND suspenders).