Import translated manuals from JM CVS Repository.

[linuxjm/jm.git] / manual / LDP_man-pages / draft / man7 / units.7

'\" t
.\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Japanese Version Copyright (c) 2002 NAKANO Takeo all rights reserved.
.\" Translated Wed 2 Jan 2002 by NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\"
.TH UNITS 7 2001-12-22 "Linux" "Linux Programmer's Manual"
.\"O .SH NAME
.\"O units, kilo, kibi, mega, mebi, giga, gibi \- decimal and binary prefixes
.SH ̾Á°
units, kilo, kibi, mega, mebi, giga, gibi \- 10 ¿Ê¤ª¤è¤Ó 2 ¿Ê¤ÎÀÜƬ¸ì
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O .SS Decimal prefixes
.SS 10 ¿Ê¤ÎÀÜƬ¸ì
.\"O The SI system of units uses prefixes that indicate powers of ten.
.\"O A kilometer is 1000 meter, and a megawatt is 1000000 watt.
.\"O Below the standard prefixes.
SI ñ°Ì·Ï¤Ç¤Ï 10 ¤ÎÎß¾è¤ò¼¨¤¹ÀÜƬ¸ì¤òÍѤ¤¤ë¡£
¥­¥í¥á¡¼¥È¥ë¤Ï 1000 ¥á¡¼¥È¥ë¡¢¥á¥¬¥ï¥Ã¥È¤Ï 1000000 ¥ï¥Ã¥È¤Ç¤¢¤ë¡£
¼¡¤Ëɸ½àŪ¤ÊÀÜƬ¸ì¤ò¼¨¤¹¡£
.RS
.TS
l l l.
.\"O Prefix     Name    Value
ÀÜƬ¸ì  ̾Á°    ÃÍ
.\"O y  yocto   10^-24 = 0.000000000000000000000001
.\"O z  zepto   10^-21 = 0.000000000000000000001
.\"O a  atto    10^-18 = 0.000000000000000001
.\"O f  femto   10^-15 = 0.000000000000001
.\"O p  pico    10^-12 = 0.000000000001
.\"O n  nano    10^-9  = 0.000000001
.\"O u  micro   10^-6  = 0.000001
.\"O m  milli   10^-3  = 0.001
.\"O c  centi   10^-2  = 0.01
.\"O d  deci    10^-1  = 0.1
.\"O da deka    10^ 1  = 10
.\"O h  hecto   10^ 2  = 100
.\"O k  kilo    10^ 3  = 1000
.\"O M  mega    10^ 6  = 1000000
.\"O G  giga    10^ 9  = 1000000000
.\"O T  tera    10^12  = 1000000000000
.\"O P  peta    10^15  = 1000000000000000
.\"O E  exa     10^18  = 1000000000000000000
.\"O Z  zetta   10^21  = 1000000000000000000000
.\"O Y  yotta   10^24  = 1000000000000000000000000
y       ¥è¥¯¥È(yocto)   10^-24 = 0.000000000000000000000001
z       ¥¼¥×¥È(zepto)   10^-21 = 0.000000000000000000001
a       ¥¢¥È(atto)      10^-18 = 0.000000000000000001
f       ¥Õ¥§¥à¥È(femto) 10^-15 = 0.000000000000001
p       ¥Ô¥³(pico)      10^-12 = 0.000000000001
n       ¥Ê¥Î(nano)      10^-9  = 0.000000001
u       ¥Þ¥¤¥¯¥í(micro) 10^-6  = 0.000001
m       ¥ß¥ê(milli)     10^-3  = 0.001
c       ¥»¥ó¥Á(centi)   10^-2  = 0.01
d       ¥Ç¥·(deci)      10^-1  = 0.1
da      ¥Ç¥«(deka)      10^ 1  = 10
h       ¥Ø¥¯¥È(hecto)   10^ 2  = 100
k       ¥­¥í(kilo)      10^ 3  = 1000
M       ¥á¥¬(mega)      10^ 6  = 1000000
G       ¥®¥¬(giga)      10^ 9  = 1000000000
T       ¥Æ¥é(tera)      10^12  = 1000000000000
P       ¥Ú¥¿(peta)      10^15  = 1000000000000000
E       ¥¨¥¯¥µ(exa)     10^18  = 1000000000000000000
Z       ¥¼¥¿(zetta)     10^21  = 1000000000000000000000
Y       ¥è¥¿(yotta)     10^24  = 1000000000000000000000000
.TE
.RE
.\"O
.sp
.\"O The symbol for micro is the Greek letter mu, often written u
.\"O in an ASCII context where this Greek letter is not available.
.\"O See also
¥Þ¥¤¥¯¥í¤Îµ­¹æ¤Ï¥®¥ê¥·¥ãʸ»ú¤Î¦Ì¤Ç¤¢¤ë¤¬¡¢
ASCII ¤Ç¥Æ¥­¥¹¥È¤¬µ­½Ò¤µ¤ì¤Æ¤¤¤Æ¡¢¥®¥ê¥·¥ãʸ»ú¤¬»È¤¨¤Ê¤¤¾ì¹ç¤Ï
u ¤È½ñ¤«¤ì¤ë¤³¤È¤¬Â¿¤¤¡£
.sp
.RS
http://physics.nist.gov/cuu/Units/prefixes.html
.RE
.sp
¤â»²¹Í¤Ë¤·¤Æ¤Û¤·¤¤¡£
.\"O .SS Binary prefixes
.SS 2 ¿Ê¤ÎÀÜƬ¸ì
.\"O The binary prefixes resemble the decimal ones,
.\"O but have an additional \(aqi\(aq
.\"O (and "Ki" starts with a capital \(aqK\(aq).
.\"O The names are formed by taking the
.\"O first syllable of the names of the decimal prefix with roughly the same
.\"O size, followed by "bi" for "binary".
2 ¿Ê¤ÎÀÜƬ¸ì¤Ï 10 ¿Ê¤ÎÀÜƬ¸ì¤È»÷¤Æ¤¤¤ë¤¬¡¢¸å¤í¤Ë \(aqi\(aq ¤¬ÉÕ¤¯
(¤Þ¤¿ "Ki" ¤Ë¤Ä¤¤¤Æ¤ÏÂçʸ»ú¤Î \(aqK\(aq) ¤Ç»Ï¤Þ¤ë)¡£
̾Á°¤Ï¡¢¤À¤¤¤¿¤¤Æ±¤¸¤¯¤é¤¤¤Î 10 ¿ÊÀÜƬ¸ì¤ÎºÇ½é¤Î²»Àá¤Ë¡¢
2 ¿Ê¿ô¤Ç¤¢¤ë¤³¤È¤ò°ÕÌ£¤¹¤ë "bi" ¤ò­¤·¤¿¤â¤Î¤Ë¤Ê¤ë¡£
.RS
.TS
l l l.
.\"O Prefix     Name    Value
ÀÜƬ¸ì  ̾Á°    ÃÍ
.\"O Ki kibi    2^10 = 1024
.\"O Mi mebi    2^20 = 1048576
.\"O Gi gibi    2^30 = 1073741824
.\"O Ti tebi    2^40 = 1099511627776
.\"O Pi pebi    2^50 = 1125899906842624
.\"O Ei exbi    2^60 = 1152921504606846976
Ki      ¥­¥Ó(kibi)      2^10 = 1024
Mi      ¥á¥Ó(mebi)      2^20 = 1048576
Gi      ¥®¥Ó(gibi)      2^30 = 1073741824
Ti      ¥Æ¥Ó(tebi)      2^40 = 1099511627776
Pi      ¥Ú¥Ó(pebi)      2^50 = 1125899906842624
Ei      ¥¨¥¯¥·¥Ó(exbi)  2^60 = 1152921504606846976
.TE
.RE
.\"O
.\"O See also
.sp
.RS
http://physics.nist.gov/cuu/Units/binary.html
.RE
.sp
¤â»²¹Í¤Ë¤·¤Æ¤Û¤·¤¤¡£
.\"O .SS Discussion
.SS ¹Í»¡
.\"O Before these binary prefixes were introduced, it was fairly
.\"O common to use k=1000 and K=1024, just like b=bit, B=byte.
.\"O Unfortunately, the M is capital already, and cannot be
.\"O capitalized to indicate binary-ness.
¤³¤ì¤é¤Î 2 ¿Ê¤ÎÀÜƬ¸ì¤¬Æ³Æþ¤µ¤ì¤ëÁ°¤Ï¡¢
k=1000 ¤È K=1024 ¤Î¤è¤¦¤Ë»È¤¦¤Î¤¬³ä¤ËÎɤ¯ÃΤé¤ì¤¿½¬´·¤À¤Ã¤¿
(b=¥Ó¥Ã¥È¡¢B=¥Ð¥¤¥È ¤Î´Ø·¸¤Ë»÷¤Æ¤¤¤ë)¡£
»ÄÇ°¤Ê¤¬¤é M ¤ÏºÇ½é¤«¤éÂçʸ»ú¤Ê¤Î¤Ç¡¢
2 ¿Ê¤Ç¤¢¤ë¤³¤È¤ò¼¨¤¹¤¿¤á¤Ë¤µ¤é¤ËÂçʸ»ú¤Ë¤¹¤ë¤³¤È¤Ï¤Ç¤­¤Ê¤«¤Ã¤¿¡£

.\"O At first that didn't matter too much, since memory modules
.\"O and disks came in sizes that were powers of two, so everyone
.\"O knew that in such contexts "kilobyte" and "megabyte" meant
.\"O 1024 and 1048576 bytes, respectively.
.\"O What originally was a
.\"O sloppy use of the prefixes "kilo" and "mega" started to become
.\"O regarded as the "real true meaning" when computers were involved.
.\"O But then disk technology changed, and disk sizes became arbitrary numbers.
.\"O After a period of uncertainty all disk manufacturers settled on the
.\"O standard, namely k=1000, M=1000k, G=1000M.
Åö½é¤Ï¤³¤Î¤³¤È¤Ï¤¢¤Þ¤êÂ礭¤ÊÌäÂê¤Ç¤Ï¤Ê¤«¤Ã¤¿¡£
¤Ê¤¼¤Ê¤é¥á¥â¥ê¥â¥¸¥å¡¼¥ë¤ä¥Ç¥£¥¹¥¯¤Ï 2 ¤ÎÎß¾è¤Ë¤Ê¤ë¤â¤Î¤À¤Ã¤¿¤Î¤Ç¡¢
³§¤½¤Î¤è¤¦¤Ê¤È¤³¤í¤Ç¤Ï¡Ö¥­¥í¥Ð¥¤¥È¡×¤ò 1024 ¥Ð¥¤¥È¡¢
¡Ö¥á¥¬¥Ð¥¤¥È¡×¤ò 1048576 ¥Ð¥¤¥È¤Ç¤¢¤ë¤È¤ß¤Ê¤·¤Æ¤¤¤¿¤«¤é¤Ç¤¢¤ë¡£
ºÇ½é¤ÏÀÜƬ¸ì¤Î¡Ö¥­¥í¡×¤È¤«¡Ö¥á¥¬¡×¤òÛ£Ëæ¤Ë±çÍѤ·¤Æ¤¤¤¿¤Î¤À¤¬¡¢
¤½¤Î¤¦¤Á¥³¥ó¥Ô¥å¡¼¥¿¤Ë´ØÏ¢¤¹¤ëÏÃÂê¤Ç¤Ï¡¢¤³¤Á¤é¤¬¡Ö¼ÂºÝ¤Î°ÕÌ£¡×¤Ë¤Ê¤Ã¤Æ¤¤¤Ã¤¿¡£
¤·¤«¤·¤½¤Î¸å¥Ç¥£¥¹¥¯¤Î¥Æ¥¯¥Î¥í¥¸¡¼¤¬Âå¤ï¤ê¡¢
¥Ç¥£¥¹¥¯¥µ¥¤¥º¤ÏǤ°Õ¤Î¿ôÃͤò¤È¤ë¤è¤¦¤Ë¤Ê¤Ã¤¿¡£
¤É¤Ã¤Á¤Ä¤«¤º¤Î»þ´ü¤¬¤·¤Ð¤é¤¯Â³¤¤¤¿¤¢¤È¡¢
¥Ç¥£¥¹¥¯¤Î¥á¡¼¥«¡¼¤¹¤Ù¤Æ¤¬¡¢É¸½à¤ò»È¤¦¤³¤È¤Ë¹ç°Õ¤·¤¿¡£
¤¹¤Ê¤ï¤Á k=1000, M=1000k, G=1000M ¤Ç¤¢¤ë¡£

.\"O The situation was messy: in the 14k4 modems, k=1000; in the 1.44MB
.\"O .\" also common: 14.4k modem
.\"O diskettes, M=1024000; etc.
.\"O In 1998 the IEC approved the standard
.\"O that defines the binary prefixes given above, enabling people
.\"O to be precise and unambiguous.
¾õ¶·¤Ï¤Ò¤É¤¯¤Ê¤Ã¤¿¡£14.4k ¥â¥Ç¥à¤Ç¤Ï k=1000,
1.44MB ¥Õ¥í¥Ã¥Ô¡¼¤Ç¤Ï M=1024000 ¤Ë¤Ê¤Ã¤¿¡£
1998 ǯ¤Ë¡¢IEC ¤Ï¾åµ­¤Î¤è¤¦¤Ê 2 ¿ÊÍѤÎÀÜƬ¸ì¤ò¾µÇ§¤·¡¢
¤³¤ì¤Ë¤è¤Ã¤Æξ¼Ô¤ò¤Ï¤Ã¤­¤ê¶èÊ̤¹¤ë¤³¤È¤¬²Äǽ¤Ë¤Ê¤Ã¤¿¡£

.\"O Thus, today, MB = 1000000B and MiB = 1048576B.
¤·¤¿¤¬¤Ã¤Æº£Æü¤Ç¤Ï¡¢MB=1000000B ¤Ç¡¢MiB = 1048576B ¤Ê¤Î¤Ç¤¢¤ë¡£

.\"O In the free software world programs are slowly
.\"O being changed to conform.
.\"O When the Linux kernel boots and says
¥Õ¥ê¡¼¥½¥Õ¥È¥¦¥§¥¢¤ÎÀ¤³¦¤Ç¤â¡¢
¥×¥í¥°¥é¥à¤¿¤Á¤Ï¤æ¤Ã¤¯¤ê¤È¤³¤ì¤é¤Ë½àµò¤·¤Æ¤­¤Æ¤¤¤ë¡£
Linux ¥«¡¼¥Í¥ë¤Ï¡¢¥Ö¡¼¥È¤¹¤ë¤È¼¡¤Î¤è¤¦¤Ê¥á¥Ã¥»¡¼¥¸¤ò½Ð¤¹¡£
.\"O
.sp
.RS
.nf
hda: 120064896 sectors (61473 MB) w/2048KiB Cache
.fi
.RE
.\"O
.sp
.\"O the MB are megabytes and the KiB are kibibytes.
MB ¤Ï¥á¥¬¥Ð¥¤¥È¤Ç¡¢KiB ¤Ï¥­¥Ó¥Ð¥¤¥È¤Ç¤¢¤ë¡£