Sticking With TapeFor the Time Being
We need to avoid the assumption that tape isn't a competitive solution.Massive reels of magnetic tape are a long-standing visual cliché. Those spinning reels are almost as popular as walls of blinking lights when a movie director needs to tell the audience, "Here is a big computer." So it could remain for decades to come because magnetic tape (with or without those photogenic reels) refuses to be displaced as a storage mediumwhile technical, even social, demands on our IT systems are dramatically expanding our need for low-cost archival. The more you know about tape, the harder it is to believe that it works. As tape is wound from one reel to another, the flexible backing stretches; the magnetic coating stretches less, leading in the long run to flaking and shedding. When a magnetic field is applied to produce a record, there isnt a simple proportion between the strength of the field and the strength of the persistent change in the magnetic state. That nonlinear relationship requires well-tuned electronics, as well as a recording head that can focus the field on the smallest possible area so that data can be recorded at maximum density.
But tape refuses to knuckle under to the fact that it shouldnt work nearly as well as it does. At half a cent per megabyte of storage, tape is dirt-cheap; at 20 to 30 years of shelf life, tape satisfies our enterprise needs for even what we call long-term storage.