Innovations

in tape storage automation at IBM In the mid-1980s, tape storage appeared to be heading toward the graveyard. Storing information on large reels of tape that had to be manually mounted was expensive, inefficient, and prone to human error. In addition, competition from hard disk drives (HDDs) was growing. Data access on HDD was faster because the data was stored in a manner for rapid random access, not linearly as on tape, and HDD capacity was rapidly growing. Then, in 1984, IBM introduced the half-inch tape cartridge (3480), which was novel in its small form factor. In 1986, an automatic loading mechanism followed. In 1987 and 1988, competitors introduced the first automated tape libraries to use the half-inch tape cartridge. Suddenly, tape storage became considerably easier to use and more efficient. With automation, it also represented the least expensive way to store data. In 1993, IBM introduced the 3495 tape library, and now offers several different automated libraries ranging from the smaller 3575 MP and 3581/3583 models to very large libraries such as the 3494 and 3584 models. This paper examines the history of IBM tape storage and automation products, including the engineering challenges that were met in response to users ’ pressing requirements; it also examines the future of automated tape storage. Background In May 1952, IBM introduced tape as a data storage medium—the first available alternative to bulky, slow punch cards. Four years later, in 1956, IBM introduced its new invention, the hard disk drive (HDD), giving customers new storage options with a potential to compete with tape storage. However, through the early decades of IBM tape history, tape storage remained the most costeffective and reliable storage option, and offered significantly higher capacity than any competitive technology. Tape is viewed as a reliable method of storing data. The stability of the media is such that a customer can typically expect to read a tape that was written and locked away more than ten years ago, whereas HDDs must be activated periodically to confirm that the lubricants remain evenly distributed and that the head is still mobile. In addition, the tape reel can be stored in a completely separate