[RC5] Long-term projects: exponential and logarithmic growth

Daniel Quintiliani danq at ptd.net
Mon Sep 6 08:52:09 EDT 2004

Hash: SHA1

> On 4 Sep, 2004, at 22:10, Daniel Quintiliani wrote:
> > Remember a month ago I suggested that with long-term distributed 
> > computing projects,
> > logarithmic growth is a better estimate than exponential growth 
> > because people leave the
> > project or die as processing power grows?

> Looking at the graphs, though, RC5-72 looks like it roughly 
> approximates some kind of linear growth (the dip in keyrate this summer 
> and last can probably be explained by people turning computers off 
> during the summer). 

A linear trendline produces:

y = 3.0401x + 53.134
R^2 = 0.8519
89 years 1 month

A logarithmic trendline produces:

y = 43.762Ln(x) - 3.6719
R^2 = 0.8645
454 years 6 months

They're both pretty close. However, I still think logarithmic growth is a better
estimate. Besides people leaving and dying, not everyone upgrades their
computers right away, and due to compatibility problems, this may be
worse in the future. Just look at the problems to get XP adopted, the fact that
no one is downloading XP SP2 because it breaks apps, and the coming 
Longhorn/TCPA/NGSCB, which will obsolete everything and require all new

- -Dan
Version: GnuPG v1.2.5 (MingW32)
Comment: http://danq.lunarpages.com/


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