Data density duel at dawn

There is a pitched battle underway to be the company with the highest areal recording density in the industry. Competing claims are coming in faster than the rivers in the UK are bursting their banks.

Samsung says it has just finished testing technology that is capable of recording 60Gb of data per square inch. This, it says, is the worlds highest areal density and four times higher than anything available from IBM. IBM says that it is an unfair comparison since its products are actually shipping, while Samsungs is still in the laboratory stage.

A spokeswoman for IBM said: "At CeBIT last spring, Samsung demonstrated a desktop drive at 15.3GB per platter for shipment in June 2000. That would work out to an Areal Density of about 11Gb per square inch, substantially lower than their technology demonstration at 60."

Toshiba, meanwhile, is working on a manufacturing process that will be capable of an areal recording density of 1Tb per square inch. It concedes, however, that it hasn't done any tests yet, but remains adamant that the manufacturing process will work.

The process uses a polymer formed through a chemical bonding of polystyrene and polymethyl methacrylate. Correctly balanced ratios of the two ingredients will lead to balls of the latter being suspended in a matrix of the polystyrene.

The disk is coated with the polymer which is then etched so that small holes of about 20nm form on the surface. These are then selectively filled with magnetic material and the gaps between them are filled with glass, or something similar. The final step is to polish the surface of the disk.

Reports have suggested that the technology could eventually lead to a bit per particle storage. However, that seems unlikely, given the unavoidable impurities in crystals.

Dr Alison Mainwood, a theoretical physicist at King's College London's Solid State research group said that in this case, the etching process used to set up the matrix of holes would limit the areal density. "When the holes get too close together, defects and impurities would mean that they join up," she said. ®