Thu 26 Jun 2008 12:28:37 PM UTC, original submission:
Wget displays or refers to quantities using power-of-two units (e.g. 1024, 1048576, etc.) but incorrectly applies prefixes that are defined as power-of-ten units (e.g. the prefix 'k' is 1000, 'M' i 1000000, etc.).
I've just found the next one:
Length: 19,189,400 (18M)
It'ld have to be marked as:
19MB (as 19 * 10^9 B)
10MiB (as 18 * 2^20 B)
Further explanation can be found at IEC[0], BIPM[1], wikipedia[2], and the US National Institute of Science and Technology[3]. There is software that correctly apply powers-of-ten and powers-of-two units to the corresponding quantities including 'linux' and 'coreutils', along with many application packages[4].
This bug report asks that the software be modified such that quantities and unit prefixes are in agreement as per the standards. This is done by changing either (or both) the quantity calculations or the unit prefixes such that they correspond correctly according to the relevant standards.
For example, if a quantity of 8178892 bytes is displayed as "7.8 MB", this is incorrectly showing a power-of-two quantity with a
power-of-ten unit. This can be resolved either by displaying the quantity as "7.8 MiB" (power-of-two quantity and unit) or as "8.18 MB" (power-of-ten quantity and unit). The degree of precision and rounding follows normal rules; what is addressed here is that the quantity and unit agree.
Similarly, if the software interprets input in power-of-two units, the program prompts and documentation should specify the correct unit for this. E.g. input which will be interpreted in units of 1024 bytes should be prompted for as "kibibytes" or "KiB", and the documentation should not refer to some other unit for the input.
[0] http://www.iec.ch/zone/si/si_bytes.htm
[1] http://www.bipm.fr/en/si/prefixes.html
[2] http://en.wikipedia.org/wiki/Binary_prefix
[3] http://physics.nist.gov/cuu/Units/prefixes.html
[4] http://en.wikipedia.org/wiki/Binary_prefix#Adoption
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