1. Montek Singh COMP790-084 Sep 8, 2011

2.  Previous class: ◦ Basics of magnetism ◦ Nanomagnets and their coupling  TODAY: ◦ Challenges and Benefits  reliability and yield  speed  energy ◦ Open questions  clocking?  suitable architectures  externally controlled inputs?  integration with storage?

3.  Yield only 25%!

4.  Individual gates can function at THz speeds  Clocking limits operation to 100 MHz or so

5.  Gates extremely energy-efficient ◦ dissipation below 1 eV per switching event ◦ 10^10 gates would dissipate ~0.1W power  assuming 100 MHz operation ◦ Another experiment indicates at least 100x energy benefit  Clocking dissipates more energy

6. Need complex multiphase clocking

7.  Questions ◦ how many phases ◦ what phase relationships

8.  Architectural problems: ◦ “layout=timing” problem  how to arrange to maintain data coherence? ◦ how to feed back data values? ◦ can we have a “real data clock” signal as well?

9.  How to provide external inputs? ◦ so far, experiments only provide constants!

10.  Can we combine processing with magnetic storage? ◦ smart disks! ◦ smart magnetic RAMs (MRAMs)!