Atomic Bits

Nestled in the hills of south San Jose, California, next to a county park, lies the intellectual birthplace of the disk drive. IBM's Almaden Research Center is home to some of the most creative and brilliant people you'll ever meet. Recently, these experts gathered to discuss the future of storage systems.

There was the expected talk about cobalt, chrome, and platinum underlayers with magnesium-oxide or nickel-aluminum coatings, and of inductive write heads made of various metallic nitrides. David Thompson, IBM Fellow and director of the Advanced Magnetic Recording Lab, discussed the superparamagnetic limit (which basically says that the smaller you make the particles, the sooner they forget what you t ell them); described optical storage and supersphere solid immersion lenses; talked a bit about the incredible potential of holographic storage (see "What's Next?," April BYTE); and mentioned the theoretical density limit of 10*15 bits per square inch (the size of an atom).

It was a lead-in to a surprise speaker: Don Eigler, another IBM Fellow. Eigler works with Almaden's scanning tunneling microscope (an IBM invention that won two scientists the 1986 Nobel Prize). He explained how the microscope works--basically it senses the distance between a surface and the microscope's head--and gave some examples of what it can "see." Most of the audience got its first look at what a single atom looks like (a gray tennis ball, if you want to know).

Eigler brought up the massive screen at the front of the auditorium and flipped a few switches. Suddenly we were seeing a live feed from the STM at the other end of the building. The STM isn't just good for looking at a toms, Eigler explained; it can move them, one by one. He donned a data glove (whose inventor, Tom Zimmerman, recently joined IBM at Almaden). The room fell silent. Then he "picked up" a xenon atom and moved it. The silence was broken by the ovation from the roomful of seasoned skeptics.

The experts aren't quite sure what scanning tunneling microscopy will do for disk drives, but the results will be about as far from the 305 RAMAC (IBM's first disk drive system) as the space shuttle is from a paper airplane.