In Brief
Super-Computer Explains Data Storage
The physics behind data storage on DVDs is still not completely clarified. The DVD's layer carrying the information consists of a polycrystalline alloy which can assume an unordered or an ordered structure. In this structure, the digital information is stored by way of bits, each of which is barely 100 nanometres small. The transition between the two phases lasts only a few nanoseconds and can be triggered by a laser beam. Researchers from Jülich, Finland and Japan now have looked deeper into the writing process. In addition to experimental Data and X-ray spectra, they created simulations using the Jülich super-computer JUGENE. Thus they were able to develop a model for the fast phase transition in the information storage process. For this, some 640 atoms were simulated over the comparatively long time-span of several hundred picoseconds in order to obtain the required precision. Around 4,000 processors of the Jülich super-computer JUGENE were used to full capacity over the course of four months to determine the correct model conditions. The greater theoretical understanding of the processes in inscribing a DVD can support the targeted development of improved phase-changing materials enabling storage media with increased capacity, longer data durability or reduced access time.
