Yottabytes Are a Lotta Bytes

By STEPHEN BECK
Now that kilo-, mega- and even gigabytes of computer memory look like small beer, and computer clock speeds even in nanoseconds begin to feel pokey, it1s time to learn the next set of exponential prefixes destined to enter the modern vocabulary. Brace yourself for the coming world of computers with yottabyte memories and zeptosecond clock speeds (and Government deficits measured in petabucks).

Really Big Numbers

PREFIXPOWER
of 10		 UNITSNUMBER
kilo-3thousands1,000
mega-6millions1,000,000
giga-9billions1,000,000,000
tera-12trillions1,000,000,000,000
peta-15quadrillions1,000,000,000,000,000
exa-18quintillions1,000,000,000,000,000,000
zetta-21sextillions1,000,000,000,000,000,000,000
yotta-24septillions1,000,000,000,000,000,000,000,000

How long would it take someone to download a one- yottabyte file using a 28.8 baud modem? 11 trillion years.

Really Small Numbers

PREFIXPOWER
of 10		 UNITSNUMBER
milli-­3one thousandth.001
micro-­6one millionth.000001
nano-­9one billionth.000000001
pico-­12one trillionth.000000000001
femto-­15one quadrillionth.000000000000001
atto-­18one quintillionth.000000000000000001
zepto-­21one sextillionth.000000000000000000001
yocto-­24one septillionth.000000000000000000000001

Source: National Institute of Standards and Technology

Illustration: Randy Jones for The New York Times

Copyright 1996 The New York Times Company