|
|
| Author |
Message |
| 25 new of 122 responses total. |
ball
|
|
response 71 of 122:
| 
Dec 21 21:36 UTC 2006 |
S.I. says one k is 1,000.
|
maus
|
|
response 72 of 122:
|
Dec 21 23:07 UTC 2006 |
The problem is that both pow(10,3) and pow(2,10) are correct, depending
on the context. System Internacional uses it to represent the former,
while computers (which 'think' in base-2 rather than base-10) use it to
refer to the latter. As an approximation, they are close, but the
difference does matter.
|
cross
|
|
response 73 of 122:
|
Dec 21 23:10 UTC 2006 |
That's the great thing about standards: there are so many to choose from.
Why is one kilobyte considered to be 2^10 = 1024 bytes? Why do disk vendors
give capacities of hard drives measured in 1k = 1000 bytes, when the
operating system views things as power of two block sizes? Which is more
standard than the other?
I'll grant that the 1,000 bits == 1 kilobit definition is standard, but it
is not universal.
|
ball
|
|
response 74 of 122:
|
Dec 21 23:17 UTC 2006 |
10^3 is k, per SI. 2^10 is K, per longstanding convention.
|
ball
|
|
response 75 of 122:
|
Dec 21 23:18 UTC 2006 |
Disk vendors don't specify disk capacity in K or k. They
use Gbytes or Mbytes and adhere to the S.I. definitions of
those.
|
cross
|
|
response 76 of 122:
|
Dec 21 23:22 UTC 2006 |
Regarding #74; I don't ever remember seeing that, but maybe I wasn't looking
in the right places.
Regarding #75; Actually, if you want to pick nits, they do: the G or M or K
just refers to 9, 6, or 3 as an exponent for 10. So, technically, Gbytes are
in the same equivalence class modulo 10. But my point was that disk vendors
rate their products in terms of powers of ten, not powers of two. Saying
KB was just convenient, as the kilobyte is essentially the first `real' unit
in common usage after the byte (that is, few people talk in terms of decibytes
or centibytes).
|
maus
|
|
response 77 of 122:
|
Dec 21 23:48 UTC 2006 |
resp:76
Picking more nits, decibyte is 1/10th of a byte. Dekabyte is 10 bytes.
Of course, with word-lengths in powers of 2 (32 or 64), dekabyte is sort
of an awkward amount of data.
|
cross
|
|
response 78 of 122:
|
Dec 21 23:54 UTC 2006 |
My bad.
|
ball
|
|
response 79 of 122:
|
Dec 22 00:22 UTC 2006 |
Re #73: k != K
|
cross
|
|
response 80 of 122:
|
Dec 22 00:29 UTC 2006 |
Like I said, that's the first I've heard of that. Got a citation?
|
ball
|
|
response 81 of 122:
|
Dec 22 00:36 UTC 2006 |
K != k just as M != m (M is 1,000,000 and m is 0.001).
|
cross
|
|
response 82 of 122:
|
Dec 22 00:37 UTC 2006 |
Ah, I see what you mean now. I thought you meant K = 2^n while k = 10^n or
something. Yes, you are right.
|
ball
|
|
response 83 of 122:
|
Dec 22 00:38 UTC 2006 |
Apparently the International Electrotechnical Commission
(whoever they are) want us to use "Ki" in place of K for
1,024. Computer people have been using K for 1,024 for a
very long time though.
|
ball
|
|
response 84 of 122:
|
Dec 22 00:39 UTC 2006 |
Re #81: 1K = 1,024 1k = 1,000.
|
ball
|
|
response 85 of 122:
|
Dec 22 00:39 UTC 2006 |
Erm, that was Re #82 ;-)
|
cross
|
|
response 86 of 122:
|
Dec 22 00:41 UTC 2006 |
Regarding #84; You know, I've never heard that before. Like I said, do you
have a citation?
|
ball
|
|
response 87 of 122:
|
Dec 22 00:43 UTC 2006 |
I'll have a rummage for one.
|
cross
|
|
response 88 of 122:
|
Dec 22 00:44 UTC 2006 |
This is interesting:
http://en.wikipedia.org/wiki/Kibibit
They seem to use ``Kib'' or ``Kibit'' (with a capital K) instead of ``Kbit''
or ``Kb.'' They do acknowledge that ``kilobit'' can be either 2^10 or 10^3
depending on context.
|
cross
|
|
response 89 of 122:
|
Dec 22 00:48 UTC 2006 |
This is also interesting:
http://en.wikipedia.org/wiki/Binary_prefix
Note that they say that in the SI system, `K' (capitalized) stands for Kelvin,
as a unit of temperature, and `k' (lowercase) only stands for `kilo.' They
say that outside of SI, K and k are mostly interchangable, and can refer to
either 2^10 or 10^3, as I had originally said. To wit:
'The one-letter abbreviations are identical to SI prefixes, except for "K",
which is used interchangeably with "k" (in SI, "K" stands for the kelvin, and
only "k" stands for 1,000).'
However, they do say that as of 2005, the binary meanings are deprecated.
|
ball
|
|
response 90 of 122:
|
Dec 22 00:53 UTC 2006 |
k (as a multiplier prefix) should only ever be used to mean
1,000. Everywhere I've ever worked or studies, K has been
capitalised to differentiate it from k. Telecomms people
talk in terms of kbits/sec, and mean 1,000 bits. Computer
people talk in Kbytes and mean 1,024. It's not rocket
science ;-)
|
ball
|
|
response 91 of 122:
|
Dec 22 00:58 UTC 2006 |
Here's an example of K from a PDP-11 manual...
http://pdos.csail.mit.edu/6.828/2005/pdp11/pdp11-40-000009.html
|
ball
|
|
response 92 of 122:
|
Dec 22 01:12 UTC 2006 |
Here's a KIM-1 manual from 1976...
http://users.telenet.be/kim1-6502/6502/usrman.html
|
mcnally
|
|
response 93 of 122:
|
Dec 22 01:12 UTC 2006 |
re #90: You're right that "it's not rocket science", but
it's not universally or consistently applied, either, which
means making assumptions based on the use of "k" or "K" is
dangerous if you need better than approximate numbers.
|
ball
|
|
response 94 of 122:
|
Dec 22 01:16 UTC 2006 |
It's been consistently applied in my experience, but it's
true that a few people don't use it correctly.
|
ball
|
|
response 95 of 122:
|
Dec 22 01:21 UTC 2006 |
Take a random sample of computer manuals, text books (I hope
they're right!) or EPROM / SRAM data sheets. K = 1,024 is a
long-standing convention.
|