Storage media cartridge handling apparatus with up-down drive arrangement disengageable with accessor carriage

Storage media cartridge handling apparatus is disclosed that comprises: a frame to support first and second laterally spaced arrays of cartridge access locations extending in a front-back direction, and at least one laterally extending further array of cartridge access locations, the cartridge access locations facing inwardly of the frame; an up-down drive arrangement disengageably engageable with an accessor carriage to move the carriage up and down in a region between the first and second arrays, to access locations in the first, second and further arrays; and at least one lateral displacement path within the frame along which the carriage can exit and enter the frame laterally. A storage media cartridge library and an accessor carriage are also disclosed.