memory reported less than installed

[Johnny Rosenberg]

2008/8/11 NoOp <glgxg at sbcglobal.net>

> On 08/11/2008 11:10 AM, Rashkae wrote:
> > Joep L. Blom wrote:
> >> Rashkae schreef:
> >>> Bill Walton wrote:
> >>>
> >>>> uname -a returns
> >>>>
> >>>> Linux ubuntu-desktop 2.6.24-19-generic #1 SMP Fri Jul 11 21:01:46 UTC
> 2008
> >>>> x86_64 GNU/Linux
> >>>>
> >>> Welp, I'm out of ideas.. you have approx 300MB vanishing into the
> ether,
> >>> and I know not why.
> >>>
> >> The 1 Gb mentioned by the vendor is based on 1 kb = 1000 byte while the
> >> OS 1 kb= 1024 byte. This sells more Gb.
> >> Joep
> >>
> >>
> >
> > This applies to Hard drives,, as far as I know, all memory makers report
> > memory modules in 'Binary Metric"
> >
>
> These might be of interest:
> http://physics.nist.gov/cuu/Units/binary.html
> http://kerneltrap.org/node/340
> [Linux: Megabytes (MB) or Mebibytes (MiB)? - note the date]
> http://tldp.org/LDP/tlk/mm/memory.html
> [old but useful]
> http://kerneltrap.org/node/2450
> [Feature: High Memory In The Linux Kernel]
>
> <
> http://www.informit.com/content/images/0131453483/downloads/gorman_book.pdf
> >
> [Understanding the Linux Virtual Memory Manager  By Mel Gorman]
>
>
> Also note that System Monitor 2.20.1 (Gutsy) uses MB whereas System
> Monitor 2.22.3 (Hardy) uses MiB.
> Ubuntu's changelog doesn't show details:
> https://launchpad.net/ubuntu/+source/gnome-system-monitor
> but Debian's does:
> <
> http://packages.debian.org/changelogs/pool/main/g/gnome-system-monitor/gnome-system-monitor_2.22.3-1/changelog
> >
>
> Regarding memory manufacturer's, this is interesting:
> http://www.edgetechcorp.com/support/technical-glossary.asp
> <quote>
> MEGABIT
> Amount of memory equal to 1,048,576 bytes of data.(abbreviated MB)
>
> Megabyte
> A megabyte is composed of 1024 kilobytes or 1,048,576 bytes. Megabyte is
> commonly abbreviated using 'M' or 'Mb'. NOTE: In many cases, an megabyte
> is incorrectly stated as being 1 million bytes.


No, that's not incorrect.
1 MB=1000000 bytes
1 MiB=1048576 bytes
This is called IEEE
1541<http://freedos-32.sourceforge.net/showdoc.php?page=standards#ieee1541>
.
It would be so much easier if everybody followed it. Some programs seems to
support it, such as GParted and a few more that I've seen.
I also find it weird that Megabytes sometimes is abbreviated Mb. In that
case, how do they abbreviate Megabits?
I was watching the Olympic games the other day and saw that they abbreviated
kilograms KG! Very strange. K does not mean kilo and G does not mean grams.
K means Kelvin and G means Giga. Kilograms=kg.
By the way, "kilo" comes from the Greek "khiloi" and means"thousand" in
English. NOT 1024. Read more about that
here<http://www.jamesshuggins.com/h/tek1/prefixes.htm>,
if you like. I find it interesting, but that's me.
And oh, 10 GB=9.31 GiB so I don't think that prefix confusion is the reason
for the OP's problem.
J.R.


>
> </quote>
>
> Yet:
> http://physics.nist.gov/cuu/Units/binary.html
> Examples and comparisons with SI prefixes
> one kibibit      1 Kibit = 2^10 bit = 1024 bit
> one kilobit      1 kbit = 10^3 bit = 1000 bit
> one mebibyte     1 MiB = 2^20 B = 1 048 576 B
> one megabyte     1 MB = 10^6 B = 1 000 000 B
> one gibibyte     1 GiB = 2^30 B = 1 073 741 824 B
> one gigabyte     1 GB = 10^9 B = 1 000 000 000 B
> http://physics.nist.gov/cuu/Units/bibliography.html
>
>
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