Defect Tolerance at the End of the Roadmap

Abstract

Abstract

Fault‐ and Defect‐Tolerant Architectures for Nanocomputing

“…defective. One of the easiest test circuits proposed for such purposes is a counter circuit [21]. Counter circuits with thresholds of t can indicate 0,1,2,y,t or more than t defects.…”

“…Reconfigurable fabrics are composed of programmable logic elements [like configurable logic blocks (CLBs)] and interconnects which can be configured to implement any logic circuit. It is expected that reconfigurable fabrics made from next generation fabrication processes will go through a postfabrication defect mapping phase during which these fabrics are configured for self-diagnosis [20,21]. Thus, defect tolerance in such fabrics can be achieved by detecting faulty components during an initial defect map phase and excluding them during actual configuration.…”

“…There are two general classes of defect mapping and avoidance techniques: (i) techniques that use test circuits to find the location and number of defects on a reconfigurable nanofabric [19,21], and (ii) broadcast-based methods that flood test packets through the whole nanofabric to locate nonreachable nodes [22]. The test circuits or packets placed on the fabric during the self-diagnosis phase utilize resources that are available later for normal logic mapping.…”

“…The proposed nondeterministic defect-mapping technique [23][24][25] is based on a variant of the RPF broadcast scheme [22] and on the defect-mapping methodology proposed in [21]. Simple test circuits from [21] are configured physically on the nanofabrics to determine the probability of the crossbar junctions being defective. These defect rates are used in determining the probability of successfully configuring all the PEs with the same broadcasting functionality.…”

“…The differences between this methodology and the methodologies in [21,22] are as follows: [21] uses extensive on-line testing to improve the recovery metric whereas this methodology only uses limited on-line testing. [22] proposes a deterministic broadcast algorithm that has been extensively modified to a non-deterministic broadcast algorithm.…”