[Beowulf] A start in Parallel Programming?

Joe Landman landman at scalableinformatics.com
Wed Mar 14 10:33:58 PDT 2007

Peter St. John wrote:
> Joe Landman wrote:
> "...if you buy into the notion that there may in fact be some 
> fundamental physical limits on Moore's law due to the nasty combination 
> of thermodynamics (stability of small structures with respect to 
> temperature, and resistance of same to defect formation), and  quantum 
> mechanics ..."
> Yeah I buy into that. I figure that there's a ceiling of so many 
> Deliverable FLOPS per Cubic Angstrom? And I wonder if something like 


> Nonvolatile Memory vs Processing Bits per Second are sortof a Heisenberg 
> Dual; if you want a bit carved in stone, so it will still be there when 
> you look later, you won't be able to process it as fast as someting 
> transient. So you could maximize the amount of FLOPS in a milliliter, or 
> the amount of RAM, but not both.


> So maybe the ceiling will be (Deliverable FLOPS times Recoverable Bytes)/ml

I rather like the Strossian MIPS per kilogram ... :)

> I think acheiving zero degrees kelvin, watching time zero in a 
> telescope, and the ceiling for DP are all kinda the same thing, and 
> we'll entertain ourselves reducing temp below 0.001K (whatever) and 
> watching t < 0.00001 sec and so on, for decades. Maybe we got within a 
> certain kind of ballpark of 0K first, now we're getting to the ballpark 
> of time 0 cosmologically, and maybe in a few decades we'll get in the 
> ballpark of Max DFLOPSRB/ML (tm).
> Robert?

Unfortunately the issue of thermodynamic stability of small structures 
is more of an issue.  It is also, unfortunately, not science fiction.

Defects happen.

Back when blue LEDs were being developed, they had an interesting 
thermodynamic stability problem.  They would destroy themselves in a few 
minutes of operation due to threading defects.  That is, the barrier to 
migration was low enough that at 300K, they would start ripping 
themselves to shreds.  Took a few years (and some materials changes) to 
fix this.

Thermodynamics:  its not just a good idea, its the law.

  (3 or 4, I forget)
Zeroth: You must play the game.
First: You can't win.
Second: You can't break even.
Third: You can't quit the game.


Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at scalableinformatics.com
web  : http://www.scalableinformatics.com
phone: +1 734 786 8423
fax  : +1 734 786 8452 or +1 866 888 3112
cell : +1 734 612 4615

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