memory reported less than installed

[NoOp]

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.
</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