half-inch tape

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.

Open Reel Tape

Although organizations have migrated to cartridge formats, legacy applications remain that still use open reels.

They're Still Around

Tens of thousands of half-inch open reels still exist in data libraries all over the world. Each standard that is widely used in the computer field hangs around for many years after it is no longer popular.