Data cartridge library with rotating storage stacks

An automated library for storing and retrieving a plurality of like-sized data storage cartridges, comprising:

• a plurality of rotatable stacks, each rotatable about an axis, all of said stacks having parallel said axes, each said stack having four outer faces, each generally parallel in one dimension to said axis of said stack, forming a corner between each two adjacent said faces, two of said stack faces each having two adjacent rectangular columns of cells offset, from said axis of said stack to opposite sides of said stack face, toward respective corners of said stack face, with at least one dimension of said rectangular columns of cells aligned parallel to said axis of said stack, faces of said cells of said adjacent columns angled with respect to each other to face towards a common central line parallel to said axes, said cells having openings for storing said like-sized storage cartridges;
• at least one read/write drive for reading and/or writing said data storage cartridges;
• a picker rotatable about an axis parallel to said axes of said rotatable stacks, for accessing said like-sized data storage cartridges stored in said cells, and for transporting said like-sized data storage cartridges between said cells and said at least one read/write drive, said axis of said picker aligned with said common central line for accessing both of said two adjacent rectangular columns of cells facing said picker;
• and
• servo systems for rotating said rotatable stacks and said rotatable picker into mutually facing positions for accessing said openings of said cells of said columns of cells facing said picker with said rotatable picker.