Nanotubes. Lately, it seems like the solution to any problem we can think of lies in harnessing the capabilities of nanotubes—super-strong molecule-sized carbon pipes, which are believed to have potential uses in everything from transistors to tissue growth to infinitely rechargeable batteries. Yet even though commercial applications for nanotube technology have proven somewhat elusive, researchers are continuing to find more applications for the tiny things, and the latest mouthwatering tidbit comes from hard drive manufacturer Seagate.
Seagate has filed a patent application for a design which would use lubricant stored in carbon nanotubes. As the drive spins, the lubricant slowly leaks out of the nanotubes as a vapor, keeping the drive running smoothly and happily for its intended lifespan.
The next question, no doubt, is why would Seagate want to create a hard drive that leaks lubricant?
Hard drive platters coated with a conventional recording medium are capable of recording data to a certain, relatively low density. Greater density is important because it not only allows more data to be stored in a given space, but data can be searched and read more quickly from a higher density platter. Unfortunately, increasing the density—outside of using techniques like perpendicular recording—also increases the instability of the data. In other words, placing ones and zeros too close together increases the likelihood that one bit may "flip" its neighbor.
One solution to this problem is to use a recording medium with a high magnetic anisotropy—which is much harder to alter magnetically, but would allow data to be packed more tightly with less risk of instability. The other side of the coin is that conventional hard drive heads are incapable of generating a magnetic field strong enough to write to such materials.
Heating high anisotropy materials makes them easier to record upon, however, and techniques exist for doing just that by aiming a tiny laser beam at the area under the hard drive head. In this way, the recording medium maintains its stability and greater data density, without requiring an exotic and expensive recording head.
The flip side to heating the platter surface, however, is that the all-important lubricant film is either evaporated or decomposed by the heat, which can severely limit the life span of a drive. Replenishing that lubricant is a tricky thing, and that’s where the carbon nanotubes come in handy. Like a high-tech sponge, the nanotubes can be made to hold a supply of the lubricant, which is then emitted as a vapor around the platter to keep things running smoothly for a very long time.
Researchers are continually discovering ways to keep the storage limits of conventional hard drives several steps ahead of the flash-based memory that is predicted to eventually replace them. Nanotube-stored lubricant is one more step toward keeping hard drives around for a long time. Before you head to the store to seek out one of these new drives, however, keep in mind that they probably won’t be on the market for a some time—if ever.
Speculation time: while the basic concept seems sound, the concern that comes to my mind has to do with the practical longevity of such drives. Focusing enough heat on the platter to cause changes in the lubricant makes one wonder what the long-term stability of that lubricant will turn out to be. Decomposed lubricant sounds suspiciously like dirt to me, and I have to wonder if, while replenishing lubricant in vapor form might be helpful in the short-term, there may be performance tradeoffs down the road.