This tool can mass-generate DLT tape labels with barcodes according to your needs. Print the output on plain printer paper. You'll need a pair of scissors or a guillotine to cut to the right size. Thanks to the way DLT cartridges work, you don't need adhesive labels: simply fold the labels along the top, so the copyright notice is in the back, then fit the folded label into the DLT label holder. The wedge-like shape will keep the label in place, even in a robotic tape library.
