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Two or Ten?

Does Kilo mean exactly 1,000 or does it mean 1,024? Do you think you know? Do you want to bet?

Well, whichever way you bet, you lose. You see, it depends.

The terms Kilo and Mega and Giga are defined in International Standard ISO 31 and are based on the International System of Units (SI). The standard defines quantities and units for various fields of science and technology. Although ISO 31 is well accepted around the world, it excludes units for information content. And no other comprehensive, formal, standard specification of units exists for information technology.

This is also true for the General Conference of Weights and Measures (abbreviated CGMP).

Despite this lack of standards, the terms have a common binary meaning that is different to their decimal equivalents (e.g., 1,024 instead of 1,000).

In 1996 Markus Kuhn proposed a standard to provide a corresponding set of prefixes for use in information technology (mirroring common usage). He revised it in 1999. (NB: see links below.) It wouldn't be radically different from the existing standard, but it would provide some clarity. However, there doesn't seem to be a groundswell of support.

My Site

How Much Data Is That?How Much Data Is That?:  Do you know how big a Megabyte is? A Gigabyte? A Terabyte? Perhaps this page will help.  (How_Big)


Across the Web

The Online Hacker Jargon FileThe Online Hacker Jargon File: This link is to the primary resource page for the file. It includes links, not only to the Jargon File itself, but also to downloadable versions, information on quotation, the book version ( The New Hacker's Dictionary ), jargon construction, hacker style, history, making suggestions, etc.  (www.catb.org/~esr/jargon)

The Peta PrincipleThe Peta Principle: This online article by Jim Binder of the San Diego Supercomputer Center was a source for some of the information in this article. (www.sdsc.edu/GatherScatter/gsq394/gsq3_f1.html)

QuantifiersQuantifiers: This entry from The Online Hacker Jargon File (the online equivalent to The New Hacker's Dictionary ) not only discusses Kilo and Mega and Giga and the confusions between powers of two and powers of ten (e.g., does Kilo mean 1,000 or 1,024), but even notes the proposal for groucho and harpo as prefixes.  (www.catb.org/~esr/jargon/html/entry/quantifiers.html)

Standardized Units for Use in Information Technology or What is a Megabyte?Standardized Units for Use in Information Technology or
What is a Megabyte?
: This proposal by Markus Kuhn (made in Dec 1996 and updated in July 1999) proposes a standard to end the confusion between whether Kilo means 1,000 or 1,024.  (ftp://ftp.informatik.uni-erlangen.de/pub/doc/ISO/information-units)

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This page created:
Fri, 25.Oct.2002

Last updated:
16:20, Sat, 10.May.2014

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1000, 1024, kilo, mega, giga, kilobyte, megabyte, gigabyte, qwerty . . . 1000, 1024, kilo, mega, giga, kilobyte, megabyte, gigabyte, qwerty