The article by Charles Day about the outcome of scientific developments 10 years later caught my attention. Having worked in optical storage from the 1990s until my retirement a few years ago, I could closely watch the rise and decline of that industry. I would offer a somewhat different perspective about three-dimensional storage than that presented in the article.

Ten years ago 3D optical storage still looked quite promising, in particular because it was assumed that magnetic storage would run into the so-called superparamagnetic limit. Several companies thought that with optical and magneto-optical storage, the magnetic hard disk could be overtaken in price and capacity, but most of the companies trying to develop the 3D technology went bankrupt after spending hundreds of millions of dollars. And Day’s example, Call/Recall, never put a device on the market as far as I know.

My comments are not meant to disparage optical technology; developments in hard-disk storage capacity were just much faster than the optical-disk industry anticipated. At present, the storage density of hard disks is about 1 terabit per square inch (an ugly unit, but in common use), an order of magnitude higher than anticipated 10 years ago, and that density was achieved thanks to the application of clever physics. What we can learn from it: Not every good idea will make a fortune, particularly when one is fighting big companies like those in the hard-disk industry.