Hi Alex,
TL;DR: They are bit/byte unit prefixes kibi..., ... but abstract value suffix
symbols, which is how I think of them, and mainly how we use them. Perhaps we
should just call them all multiples or symbosl, as we only sometimes(/rarely?)
use them as unit prefixes (and seldom written out, only to explain the weird Xi
notation)? Feel free to change the titles and log messages as you see fit.
[BT;DT: Many discussions about units over the decades, including various
*industry* conventions about "accepted" units, values, and conversion factors,
invariant regardless of SI and CODATA.
ISO/BIPM etc. uses SI to mean decimal *metric* unit prefixes (and notes that SI
does not support non-physical units of information) and IEC to mean binary unit
prefixes for bits, bytes, and also allows Hertz so far. See refs from:
https://en.wikipedia.org/wiki/Binary_prefix#cite_note-bipm-book-91
Bureau International des Poids et Mesures. (2006). "§3.1 SI prefixes" (PDF). The
International System of Units (SI) (in French and English) (8th ed.). Paris:
STEDI Media. p. 127. ISBN 978-92-822-2213-3. Archived (PDF) from the original on
2006-08-13. Retrieved 2007-02-25. [Side note:] These SI prefixes refer strictly
to powers of 10. They should not be used to indicate powers of 2 (for example,
one kilobit represents 1000 bits and not 1024 bits). The IEC has adopted
prefixes for binary powers in the international standard IEC 60027-2: 2005,
third edition, Letter symbols to be used in electrical technology – Part 2:
Telecommunications and electronics. The names and symbols for the prefixes
corresponding to 2^10, 2^20, 2^30, 2^40, 2^50, and 2^60 are, respectively: kibi,
Ki; mebi, Mi; gibi, Gi; tebi, Ti; pebi, Pi; and exbi, Ei. Thus, for example, one
kibibyte would be written: 1 KiB = 210 B = 1024 B, where B denotes a byte.
Although these prefixes are *not part of the SI*, they should be used in the
field of information technology to avoid the incorrect usage of the SI prefixes.
BIPM SI Brochure 2022 edition (adding ronna/ronta, quetta/quecto, etc.) English
text only p.143 side note (the only uses of "bit" in the document; "byte" is not
used; "information" and "word" are used only in the literate senses):
https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf#page=29
"The SI prefixes refer
strictly to powers of 10.
They should not be used to
indicate powers of 2
(for example, one kilobit
represents 1000 bits and
not 1024 bits). The names
and symbols for prefixes to
be used with powers of 2
are recommended as
follows:
kibi Ki 2^10
mebi Mi 2^20
gibi Gi 2^30
tebi Ti 2^40
pebi Pi 2^50
exbi Ei 2^60
zebi Zi 2^70
yobi Yi 2^80"
...no
robi Ri 2^90
qubi Qi 2^100
yet! ;^> ]
On 2023-02-07 16:44, Alejandro Colomar wrote:
Hi Brian,
The subject is not correct, IMO. The SI also defines the Ki, Mi, ... prefixes for binary multipliers.
Also, they are prefixes, not suffixes.
Cheers,
Alex
On 2/7/23 21:11, Brian Inglis wrote:
---
man2/shmget.2 | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/man2/shmget.2 b/man2/shmget.2
index cdb2d3bee4b5..4bc18bedf3a9 100644
--- a/man2/shmget.2
+++ b/man2/shmget.2
@@ -354,7 +354,7 @@ for a discussion of why this default value (rather than
is used.
.IP
From Linux 2.2 up to Linux 3.15, the default value of
-this limit was 0x2000000 (32\ MB).
+this limit was 0x2000000 (32\ MiB).
.IP
Because it is not possible to map just part of a shared memory segment,
the amount of virtual memory places another limit on the maximum size of a
--
Take care. Thanks, Brian Inglis Calgary, Alberta, Canada
La perfection est atteinte Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut
-- Antoine de Saint-Exupéry
