A convertible media and document storage system uses elements of common pallet rack framing and is convertible between open slot and container storage. The container storage includes pilasters hanging from horizontal beam elements of the framing, and vertically spaced apart pairs of adjustable wireform racks engage the pilasters and provide horizontal ledges for supporting containers of various sizes. The use of hanging pilasters minimizes strength and material requirements. The open slot storage includes tall vertical drawers riding on overhead rails attachable to the same horizontal beam elements and individually horizontally drawn for access to the stored material such as data tape and disk media. The storage system optimizes utilization of space and allows large facilities to reconfigure storage between open slot and container storage when demands change.