Oops. In my final
paragraph, 4 700 000 should be 4 700 000 000 (or 4.7 times 10^9) and 1 048 576
should be either 1 073 741 824 ) or 2^30).
Bill Potts, CMS
Roseville,
CA
http://metric1.org [SI
Navigator]
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Bill Potts
Sent: Sunday, May 14, 2006 09:01
To: U.S. Metric Association
Subject: [USMA:36782] RE: SI in computer file sizesThose are kibibyte and mebibyte.Although consistent, in a sense, with SI, they are not SI. Rather, they are the object of an IEC (International Electrotechnical Commission) standard, written in 1998 (see http://physics.nist.gov/cuu/Units/binary.html).It's never acceptable (at least to the SI purist) to use KB; that should be kB. However, the capital K is used for the binary version (KiB).The choice of the binary or the standard prefix is dependent on the structure. As memory capacity is always a power of 2 (because of its structure), the binary prefix is always appropriate. As data communication speeds are always expressed decimally (except by those who don't know better), the binary prefix is never appropriate. Disk storage is a gray area. However, if you express its capacity as a decimal number, then the SI prefix applies. If you express it as a power of 2 (that power being 10, 20, 30, etc.), then the binary prefix applies.Getting the world to use binary prefixes (as opposed to using SI prefixes ambiguously) for things like memory size is, of course, another matter.Finally, with respect to the file you're downloading, if it's something like 4 700 000 bytes, 4.7 GB is correct. If it's about 4.7 times 1 048 576, then 4.7 GiB is correct.Bill Potts, CMS
Roseville, CA
http://metric1.org [SI Navigator]-----Original Message-----Recently I was downloading a Linux distribution off Bittorrent and happened to notice that in the software I use for it there was an option to use SI units meaning KiB for Kilobyte and MiB for Megabyte instead of KB and MB. What I don't get is why it's not acceptable to use the KB or MB. Wikipedia seems to indicate from this link http://en.wikipedia.org/wiki/Byte that either one is acceptable
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Mike Millet
Sent: Sunday, May 14, 2006 08:14
To: U.S. Metric Association
Subject: [USMA:36781] SI in computer file sizes
.
Just as a side note the file I'm downloading happens to be 4.7GiB :). It's going to take a while so I'll have plenty of time to stare at the number and ponder it.
Mike
--
"The boy is dangerous, they all sense it why can't you?"
