Locally Rewritable Codes for Resistive Memories

We propose locally rewritable codes (LWC) for resistive memories inspired by locally repairable codes (LRC) for distributed storage systems. Small values of repair locality of LRC enable fast repair of a single failed node since the lost data in the failed node can be recovered by accessing only a small fraction of other nodes. By using rewriting locality, LWC can improve endurance and power consumption which are major challenges for resistive memories. We point out the duality between LRC and LWC, which indicates that existing construction methods of LRC can be applied to construct LWC.1

Ion projection direct structuring for patterning of magnetic media

Ion projection facilitates a direct structuring, which is an attractive potential manufacturing process for patterned storage media. An advantage to this method is that the media roughness remains unchanged. The feasibility of ion projection direct structuring for processing full disk surfaces was investigated using a next generation lithography projector. Co-Pt multilayer films with strong perpendicular anisotropy were deposited on 1-in glass disks as used in the IBM microdrive and on Si substrates. Concentric tracks including data, as well as head positioning servo structures, were patterned in a single exposure step with 45 keV He+ at a 4 × demagnification. In a second experiment, sub-100-nm magnetic islands were produced using projection at 8.7 × demagnification and visualized by magnetic force microscopy