spc3r21c.pdf tupo kib != KiB

Pat LaVarre plavarre at lexarmedia.com
Sun Jan 23 05:43:58 PST 2005

* From the T10 Reflector (t10 at t10.org), posted by:
* "Pat LaVarre" <plavarre at lexarmedia.com>
> Sigh! Should we write to Webster and
> let them know that they've got it wrong?
> ...
> PS For your future reference,
> there's a minor gotcha in all this nomenclature:
>=A0=A0=A0=A0 1000 bytes =3D 1 kilobyte =3D 1 kB
>=A0=A0=A0=A0 1024 bytes =3D 1 kibibyte =3D 1 Kib
> Note the difference in capitalization of the initial letter.

News to me, yes, thank you.

This gotcha I see quoted in the examples of:
although in reverse:

one kibibit  1 Kibit =3D 2^10 bit =3D 1024 bit=20
one kilobit  1 kbit =3D 10^3 bit =3D 1000 bit

has a table of lower case and upper case SI prefixes.

There I'm reminded that M G T P E Z Y indeed are ten raised to a =
positive multiple of three, and m u n p f a z y are indeed ten raised =
to a negative multiple of three, but still a few lower case prefixes =
denote ten raised to a positive power, e.g.:

da =3D deka =3D 10^+1
h =3D hecto =3D 10^+2
k =3D kilo =3D 10^+3

Pat LaVarre

P.S. This further study reminded me:

a) The "1.44 MB" of a 3.5" floppy is 1,024,000 bytes, i.e. 1 kilokebi =
byte or 1 kebikilo byte, not 1 megabyte nor 1 mebibyte.

b) Ki Mi Gi Ti are two raised to a multiple of 10, K M G T are 10 =
raised to a multiple of three.  The number in common is the number 10 =
... all because log base 2 of 10^3 happens to be slightly more than =
9.96578 i.e. almost 10.
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