This article is from the storage FAQ part2, by Rodney D. Van Meter with numerous contributions by others.
See http://www.qualstar.com. We are now shipping our TLS-2000 4mm tape library family. This product line consists of 6 models ranging from 1-2 drives with 18 tapes, to 1-4 drives with 144 tapes. All units include a mailbox and barcode support. I believe that the TLS-24144 is the largest 4mm library in production. TLS-2000 supports Seagate, Sony and HP DDS-2 drives and we are about to start testing the Sony SDT-9000 DDS-3 drive. (Bob Covey, firstname.lastname@example.org, 96/10/22)