This article is from the storage FAQ part2, by Rodney D. Van Meter with numerous contributions by others.
Ampex makes their own autochangers for the DST DD-2 tape drive (see part 1 of the FAQ). DST 410 Automated Cartridge Library: Up to 1.2 terabytes capacity (uncompressed) in 7 square feet of floor space. All 3 cartridge (cassette) sizes supported - 25, 75, 165 gigabytes (uncompressed). SCSI Medium Changer Commands or Ethernet NetSCSI protocol. Console mounted configuration. Single unit price: $150K. DST 810 Automated Cartridge Library: Up to 6.4 terabytes (uncompressed) in 21 square feet of floor space. Robotic performance of 600 cartridge exchanges per hour. Average access time to any file less than 30 sec. (including cartridge exchange, drive load and search to data). 1 to 4 tape drives per library. Ethernet NetSCSI protocol robotics control. Starting single unit price: $300K. (firstname.lastname@example.org, 94/12/23)