Optimizing Scrubbing Sequences for Advanced Computer Memories

Advanced memories are designed using smaller geometries and lower voltages. This enables larger levels of integration and reduced power consumption, but makes memories more prone to suffer multibit soft errors. In this scenario, scrubbing is a fundamental technique to avoid the accumulation of errors, which would lead to a failure of the system. Scrubbing is usually implemented in advanced memories. However, when the percentage of multibit soft errors is significant, the scrubbing sequence (the order in which the memory is scrubbed) becomes important for the reliability of the system. In this paper, a new procedure to perform scrubbing is presented, which offers a significant improvement in the reliability. In the presence of multiple cell upsets, the mean time to failure could be doubled with respect to the traditional approach.Manuscript received September 7, 2009; revised October 30, 2009; accepted December 15, 2009. Date of publication December 28, 2010; date of current version June 4, 2010. This work was supported in part by the Spanish Ministry of Science and Innovation under Grant AYA2009-13300-C03-01, by the Regional Government of Madrid, and by the European Union FEDER Programme