This article is from the storage FAQ part1, by Rodney D. Van Meter with numerous contributions by others.
There is a second type of tape drive from IBM based on the Magstar technology. Known as Coyote or 3570, it's 2.2 MB/sec., 5GB in a two-reel cassette. Unlike 3590, the tape never leaves the cassette. The width of the tape is much less than 1/2", maybe 1/4"? The cassette is about the size of an 8mm, give or take. There's an associated desktop modular autochanger. (rdv, 97/6/5)