Reliability is a Fungible Resource Francois Impens Isaac Chuang MIT Media Laboratory Department of Physics Fungible Resources Gold Euros Mass Energy Space Time Energy Claim Reliability Space Time Energy Reliability and Area I But also Pfail A Probability Example MOSFET 0 Vth 1 Voltage Pfail Area Fungibility What tradeoffs are possible Pfail A Larger area more reliable Generic behavior Molecular Quantum Is this the best possible A Area Reliability and Area II Consider a circuit which fails with probability Circuit 2 Circuit 1 Circuit Circuit 3 Area A Pfail Vote Area 3A Pfail 3 2 Distributed Voting P1 MAJ P2 MAJ P3 MAJ Immune to any single gate failure Failure probability P1 P2 P3 P1 P2 P3 Area Dist MAJ P3 Dist MAJ P2 Dist MAJ P1 Dist MAJ Double Encoding Failure probability Recursive Encoding Recursion Area Failure probability Threshold Pfail Area Fungibility What tradeoffs are possible Pfail A Area Pfail P1 MAJ P2 MAJ P3 MAJ A A Area Example erfc A1 4 log Pfail 10 8 F 6 4 t n a r ole 10 9 P fail l a m r No Reliability Area Fungible Region 2 0 T t l au 10 12 100 200 300 Area Only for some functions Function Effective Region Conclusions Reliability Space Time Energy Fault Tolerance can save resrouces CMOS Neurons
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