Forum: english.stackexchange.com
Tags: <abbreviations>
Title: Kilo as 1 024, Mega as 1 048 576
Question: Under SI, the  kilo  prefix refers to 1,000 and mega refers to 1,000,000. In strict computer terms,  kilo  refers to 1,024 (2 10 ),  mega  refers to 1,048,576 (2 20 ) and  giga  is 1,073,741,824 (2 30 ).   The original question was how widely known outside this domain is this distinction?  Going by the answers provided, I should be using binary prefixes in order to remove the ambiguity in my documentation.

Answers:
sents: text: Not so many.
text: Most people within the computer domain aren't even aware of all the details.
text: The slightly larger kilo unit actually have gotten it's own unit, or actually a set of units.
text: 1024 bytes is one kibibyte , 1024 kibibyte is one mebibyte, and so on.
text: Even within the computer domain, both types of units are used.
text: Disk storage manufacturers for example uses 1000 as kilo to measure disk sizes, while operating systems uses 1024 as kilo to measure disk usage.
text: That means that a 2.0 terabyte disk only has room for 1.82 terabyte data.
text: (Also, as some of the space is used to keep track of the data on the disk, the actual amount that you can store on the disk is even less.)
text: Even disk manufacturers aren't consistent, and both units has even been mixed to measure the size of a single type of disk.
text: The (once) so well known 1.44 megabyte 3.25" floppy disk is actually neither 1.44 megabyte nor 1.44 mebibyte.
text: It's actually 1.44 * 1000 * 1024 bytes, or 1.44 kilo-kibi-byte...
answer_details: author: english.stackexchange.com/users/3365/Guffa
score: 13
sents: text: Not many.
text: At least that’s presumed — by the people who then invented Kibi and Mebi and Gibi .
text: Yup, there’s sort-of
text: (I don’t deign to honor them as)
text: SI prefixes: kB is kilobytes, that is, 1000 bytes (some used “KB” to signify 2 10 bytes, but that’s really nonstandard).
text: While kiB, kibibytes, is 1024 bytes.
text: Likewise for MB -> MiB (Mebibytes) and GB -> Gibibytes.
text: The bi here stands for binary, so the long longform could be Kilobinarybytes .
text: It’s all weird anyway.
text: I guess one could presume that even fewer people “outside the domain” are aware of those new binary prefixes than were aware of the old power-of-two one, if you consider that even people inside said domain are unaware of those new prefixes.
answer_details: author: english.stackexchange.com/users/2701/Jürgen A. Erhard
score: 7
sents: text: The answer is not many.
text: That's why there is an increasing move to refer to use "kibi", "mebi" and so on as prefixes for these powers of two.
text: Wikipedia has an article about it: http://en.wikipedia.org/wiki/Binary_prefix
answer_details: author: english.stackexchange.com/users/2469/Eric
score: 5
sents: text: Umm, not very many?
text: The computer definitions aren't much use outside computer stuff, so I'd say that the vast majority of non-computer people are ignorant of the distinction (or don't care enough to remember it).
text: But really, I could guess at numbers all day.
text: How on Earth would we know the answer to this?
answer_details: author: english.stackexchange.com/users/2707/bikeboy389
score: 4
sents: text: Regardless of how many people know or don't know about it, if you're writing a specification or technical publication, my suggestion is to use the binary prefixes ( kibi, mebi ), that way there is no room for ambiguity.
answer_details: author: english.stackexchange.com/users/3433/Stephen Furlani
score: 4
sents: text: Actually, kilo- , mega- , etc.
text: are ambiguous , because some think they ought to be based on powers of 2 in a computing context and powers of 10 otherwise, some disagree, and both sides just go ahead and use what they prefer.
text: To solve this, the prefixes kibi- (2 10 ), mebi- (2 20 ), gibi- (2 30 ), and tebi- (2 40 ) have been introduced; these I find are rarely used in whole form, but there's increasingly common use of their abbreviations KiB, MiB, GiB, and TiB.
text: I for one always say "K", "meg", "gig", and "terabyte".
text: The Wikipedia entry on binary prefixes sums up the issues nicely.
answer_details: author: english.stackexchange.com/users/1506/Jon Purdy
score: 3

Summary of the answers:
It's generally considered that not many people are aware of this distinction and that even many people within the computer domain are not aware of all the details. 
Not many people are aware of various SI computer units of measurement. Even disc manufacturers stick to standard 1000 as a kilo and so are inconsistent.Therefore it is presumed that even fewer people “outside the domain” are aware of those new binary prefixes than were aware of the old power-of-two one, if you consider that even people  inside  said domain are unaware of those new prefixes. However, it is important to use these prefixes if writing a technical publication.
It's generally considered that not many people are aware of this distinction and that even many people within the computer domain are not aware of all the details. 
Not many people outside the domain would be aware of this distinction. Most people within the computer domain are not even aware this. Both types of units are used in the computer domain and even disk manufacturers are inconsistent.
It is widely believed that not many people would be aware of this. One could presume that even fewer people “outside the domain” are aware of those new binary prefixes than were aware of the old power-of-two one, if you consider that even people  inside  said domain are unaware of those new prefixes.
The answer is that not many people outside of this domain are aware of this distinction and it's possible that not many people within the domain are aware of it either. In any case, using binary prefixes in technical documentation is probably advisable.