Bill
Fri Mar 28 00:52:04 PDT 2008
Bill Blanton wrote:
> "Bill in Co." <not_really_here@earthlink.net> wrote in message
> news:%23YRvxZHkIHA.1744@TK2MSFTNGP05.phx.gbl...
>> Bill Blanton wrote:
>>> "Bill in Co." <not_really_here@earthlink.net> wrote in message
>>> news:Ojjo1e9jIHA.5280@TK2MSFTNGP02.phx.gbl...
>>>> When your right click on a drive in windows explorer, and get these
>>>> different reported sizes, what is the story?
>>>>
>>>> Example, for a 20 GB partition - rounded to 3 significant digits below:
>>>> (choose whichever I guess; the two listings below are seen next to each
>>>> other in windows explorer):
>>>>
>>>> 12. 4GB 11.5 GB used spaee (tot capacity adds up to 19.9
>>>> GB)
>>>> 7.56 GB 7.04 GB free space (tot capacity adds up to 18.6
>>>> GB)
>>>>
>>>> and as yet a third variation reported in BING:
>>>>
>>>> 11.9 GB used, 7.22 GB free (total = 19.1 GB)
>>>>
>>>> Anyone have a good explanation for the differences? I assume part
>>>> of it
>>>> might have to due with the defenition of the HD sizes, e.g.: 1 GB or
>>>> 1.024
>>>> GB, for "1 GB size" - not sure?
>>>
>>> Sorta,,, and your rounding of the bytes to GB shows why it's not the
>>> same
>>> thing.
>>>
>>>> Take this last example;
>>>>
>>>>
>>>> or for a 40 GB example:
>>>>
>>>> 20.36 GB 18.9 GB used space
>>>
>>> It wasn't 20.36GB was it? It was 20,36n,nnn,nnn bytes. So, divide that
>>> number by 1024^3 (or 2^30) and you'd get roughly 18.9GB
>>>
>>>> 19.64 GB 18.2 GB free space
>>>
>>> Divide 19,64n,nnn,nnn by 1024^3, and you get roughly 18.2
>>>
>>>> capacity:
>>>> 40.00 GB 37.2 GB
>>>
>>> So, bytewise
>>>
>>> + 20,36n,nnn,nnn
>>> + 19,64n,nnn,nnn
>>> = 40,nnn,nnn,nnn
>>>
>>> but 40,nnn,nnn,nnn bytes is not 40GB (in binary terms).
>>
>> Thanks Bill. I'll have to digest this a bit more. But there is still a
>> point of confusion for me here. Giga just means 10 to the 9th, so I
>> used
>> that as shorthand, but maybe that is incorrect or misleading to do for
>> binary expressions? Well, let's see... So if the disk capacity shows
>> as 40,000,nnn,nnn bytes, it is not "correct"
>> to express it as 40 X 10^9 bytes, or 40 E +09 bytes? (even though that
>> is
>> the actual "number"?)
>
> 10^9. That's not in-correct. That's how HD manufacturers define their
> drives.
Yeah, unfortunately, unlike the rest of the computer stuff.
> And kilobits/sec, kilowatts, et al are de3fined by powers of 10.
>
> However, Windows (more correctly IMO) defines storage space in powers of
> 2.
> 40GB = 40 * 2^30 = 42,949,672,960. (and since it isn't a power of 10 you
> can't just move the decimal point to get to the next quantifier)
But I could rewrite the number above as: 42.949672960 E+09, and it would be
correct. Or as: 42.949672960 X 10^9. But that's different than 40E
+09
> Since computers are mostly binary (n^2) beasts, (CPU, memory)
> it was common in the early days to define a kilo-byte as 1024 bytes, and
> not 1000 bytes (and so was "close enough"). I think it may have taken off
> from there.
I think so too, but sometimes it still confuses me. I hate the fact that
the HD manufacturers went the other way (inconsistent with the std computer
binary approach). And I believe this was *soley* done to inflate their
numbers as an advertising gimmick. So they could sell a 40 GB drive and
people thought they got 40 GB of actual storage, but they don't.
> There was/is a movement under way to insert an "i' to denote binary ^2
> to avoid the confusion. I.e KiB, Mib, GiB, TiB. It was supported by the
> IEC
> and IEEE, but I don't think it ever really took off.
Maybe that would have helped.
There are some things the IEEE did that certainly did not help, I feel.
(e.g:: I dislike conductance being expressed in the new units of Siemens,
much preferring the good ole "mhos"; and changing to "mA" (e.g) for
milliamps in lieu of mA (this, to "honor the guys"), and using "Hz" in lieu
of the more logical "cps" (for anybody old enough to remember :-)
> Here, I found this. (see "quantifiers")
>
http://www.ccil.org/jargon/jargon_32.html#TAG1443
Thanks again.