[next] [prev] [up] Date: Mon, 19 Dec 94 10:00:04 -0500
~~~ [prev] [up] From: Allan C Wechsler <Wechsler@world.std.com >
~~~ [prev] [up] Subject: How Big is Big?
Date: Sun, 18 Dec 1994 15:56:10 -0500
From: der Mouse <mouse@collatz.mcrcim.mcgill.edu>

[Physicists] are planning soon to start sending petabytes (10^15)
over the Internet. 10^15 is getting interesting close to the size of
Rubik's cube (never mind that I thought that the proper term for
10^15 bytes was terabytes.)

I thought it was

kilo	10^3
mega	10^6
giga	10^9
tera	10^12
peta	10^15
exa	10^18

Also note that the Cube database storage size requires the highest
prefix we have. Time to get SI to think up some more, I guess :-)

(Warning to Cube-Lovers: this is off the topic, but it's a digression
I can never resist. Alan is going to come over to my house and soap
my windows for this, I just know it.)

They _have_ thought up some more -- this was in Science News about 18
months ago. But the ones they thought up are absolutely awful, and I
want to take this opportunity to advertise my own suggestions.

First note the following relationships, which I believe are entirely
the result of coincidence:

te(t)ra     1000^4	
pe(n)ta     1000^5
(h)exa      1000^6

In each case, the prefix for 1000^n looks like the neo-greek prefix
for n, with the second-to-last consonant deleted. I merely propose
that we continue this scheme:

he(p)ta     1000^7
o(c)to      1000^8
(en)nea     1000^9

I admit to a fudge with n=9, but I like neabytes better than
eneabytes, and the prefix E was already taken by n=6. I wanted to
keep up the unique sequence of prefixes: K, M, G, T, P, E, H, O, N.

For those who care, megameters are good for measuring small planets,
gigameters for big planets and stars, and terameters for solar
systems. A petameter is about a tenth of a light year, and so it's
good for measuring near interstellar distances; exameters are good for
the 100-ly range, galaxies should be measured with hetameters, and
intergalactic distances with otometers. Current theory says the
universe is considerably smaller than one neameter.

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