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On 9/29/98 Dianna Massey [dmassey -at- CELERITY -dot- COM] wrote (in part):
>In general, metric units are never capitalized
>unless they are derived from proper names.
>This is not entirely accurate -- prefixes for units above "k" generally
>capitalized. The term "megabit" is most properly abbreviated
>as "Mb" not "mb."
As Matt Ion has pointed out in a separate response on this thread,
the use of "M" vs. "m" is not a matter of "most properly", it's a matter
of correct vs. incorrect. One prefix represents a factor of one million
times while the other represents a factor of one thousandth, a
difference of 9 orders of magnitude.
Capitalization of "M" for mega is therefore not a matter of style; it's
actually a necessity. I think the usage of capitalized prefixes for SI
prefixes larger than mega (G=giga, T=tera, etc.) stemmed from a
desire to make the prefixes look more consistent rather than leave
mega as the only multiplier that used a capital letter.
But what I really wanted to comment on was the use of megabits as
the example for use of the mega prefix. One fact that we all need to
remember is that when referring to binary-based entities (bits, bytes,
etc.) the "kilo" and "mega" prefixes represent a different multiplier
than in the decimal-based scientific world. In the pervasive world of
computers, "kilo" represents a multiplier of 2^10=1024 rather than
10^3=1000, and "mega' represents a multiplier of 2^20=1,048,576
rather than 10^6=1,000,000.
Fred Ridder ( f -dot- ridder -at- dialogic -dot- com )
Senior Technical Writer