An operator alterable space is described, for use with a data storage library. The library has a frame substantially defines an interior environment and is exposed to an exterior environment. The operator alterable space is adapted to accommodate either a drive module that is capable of storing data to a magazine storage element or a shelf module capable of accommodating at least the magazine storage element whereby the magazine storage element can be disposed in the shelf module. The operator alterable space is accessible from the exterior environment for installing either the shelf module or the drive module via an opening in the frame. The operator alterable space is also accessible to a magazine transport from the interior environment, wherein the magazine transport is capable of moving the magazine storage element to the operator alterable space.