In a mass storage library, a module storage array includes a back plate having
"T" shaped apertures patterned to form a cartridge storage together with cell blocks
that have "T" shaped protrusions to fit into the openings in the back plate. A
column of cell blocks are held in place between a shelf and a spring load. Interlocking
surfaces molded into the cell blocks assist in holding the column of cell blocks
in place with the "T" shaped protrusions and openings in the back plate. The cell
blocks are stacked on the shelf with the "T" shaped protrusions inserted into the
openings in the back plate and their mating surfaces interlocked. The spring load
clamps the cell against the shelf. The cell blocks form cavities that hold the
cartridges in the storage array. A plurality of columns of cell blocks provide
the complete storage array. Calibration targets are provided to align the cell
blocks to the library accessor and reader. One strip the length of the storage
cell stack contains a bar-code viewable through each cartridge storage cell and
scannable by an accessor scanner to identify the individual cell blocks.