[Python-Dev] One more dict trick

[M.-A. Lemburg]

"Eric S. Raymond" wrote:
> 
> M.-A. Lemburg <mal@lemburg.com>:
> > In any case, this will avoid us the trouble of having to check
> > those poly numbers every time Intel decides to bump the register
> > width by another factor of two ;-)
> 
> This seems unlikely.
> 
> 2^64 = 18446744073709551616, which is roughly 10 ^ 22.  Let's assume
> a memory density, of, say 2^20 machine words or roughly 8 megabytes per
> cubic centimeter (much, *much* better than we'll be able to do for the
> forseeable future -- remember power distribution and heat dissipation).

Where did you get those numbers from ? There are memory sticks
with 128 MB around and these measure about 2.5 cm^2 * 1 mm.

> Then, approximating the cubic relation between a sphere's volume and area
> by lopping off a power of four, we see that 2^64 64-bit words of memory
> would occupy a sphere of roughly 2^(64 - 20 - 2) cm radius, or about
> 17 million kilometers.
> 
> This is roughly twice the diameter of the Sun.  64-bit computers
> aren't going to run out of address space any time soon.
> 
> 64-bit clocks counting seconds will turn over in approximately six
> trillion years, long after the expansion of the Universe will have
> dropped its energy density low enough to make computation...well,
> let's just say "difficult" and leave it at that.
> 
> Nobody needs 128 bits of integer or floating-point precision, either.
> There's basically no source of data to compute with that's got
> anywhere near 22 significant digits of accuracy -- 48 bits is
> about the most people in scientific computing ever use.

Just you wait... someday marketing people will probably invent the
world memory facility and start assigning a few hundred
Terabytes for everyone on this planet to use for his/her data 
storage -- store once, use everywhere ;-)

Let's assume we have 12e9 people on this planet by that time, then
we'll need 12e9*100e12 = 1.2e24 bytes of central storage... or
roughly 2^80 bytes per civilization.

Of course, they will want to run Python in order to manage
that data and so will all those Palm uses hooking up to the
facility... ;-)

-- 
Marc-Andre Lemburg
CEO eGenix.com Software GmbH
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