This article is from the storage FAQ part2, by Rodney D. Van Meter with numerous contributions by others.
Sony sells three autochangers for their ID-1 line of tape drives, based on their broadcast line of autochangers. These are known as the DMS Series, models 24, 300M, and 700M. Not surprisingly, they hold, respectively, 24 (S,M, or L cassettes), 300 (M only) and 700 (M only) cassettes for capacities of 2.3, 13, and 30 terabytes. They have also announced something called PetaSite, which they claim expands to 3 petabytes and supports both ID-1 and DTF in a single system. (rdv, 1996/3/22)