half-inch tape - Computer Definition
A magnetic tape format that has been in use since the 1950s. Second-generation computers used 7-track, half-inch tape in open reels that were threaded by hand. Third-generation computers used 9-track open reels. Although the maximum storage is little more than 250MB per reel, new open-reel drives have been manufactured into the 21st century. However, the market for such hardware dwindles every passing year. Half-inch reels evolved into half-inch, self-threading tape cartridges, including IBM's 3490/3490/3590 line, Quantum's DLT and StorageTek's Redwood, which hold from 800MB to 50GB. See Magstar, DLT, Redwood and magnetic tape.