Re: Use of Swap Space
On 02/01/2009 02:49 PM, Lee Glidewell wrote:
On Saturday 31 January 2009 21:01:14 David Fox wrote:
It isn't that RAM has a FAT - those things only are present on
filesystems. It is more likely that free's interpretation doesn't
include kernel memory. Also, 4gb may be 4*1024*1024 not 4*1000*1000,
although that is more likely to be a concern with hard disk capacity.
No, the issue is that manufactures advertise in *1000, while computers use
Hard drive manufacturers, not RAM manufacturers.
My beard's grey enough to remember when drive manufacturers measured
drive capacity in binary KB, not decimal.
bytes in *1024. The recent convention that's come into place to represent this
is between Kilo/Mega/Giga-bytes (*1000) and Kibi/Mebi/Gibi-bytes (*1024).
So a stick of memory advertised as 4 Gigabytes is going to present itself to
your computer as 3.84 Gibibytes, roughly.
If that were true, I'd have 8 * 10^9 bytes of RAM, and this
demonstrates that error:
$ calc 8 \* 10\*\*9 / 1024
7812500
$ cat /proc/meminfo | grep MemTot
MemTotal: 8177796 kB
$ calc 8177796 \* 1024
8374063104
$ calc 2\*\*30 \* 8
8589934592
The only issue is that I'm "missing" 215871488 bytes (52703 of 4KB
pages).
http://xkcd.com/394/
But seriously: KB was always the standard way of writing kilobyte.
Kb was/is kilobit (now, Mb and Gb are relevant), used my memory
manufactures to indicate the capacity of individual *chips* (not the
SIMMs on which they are mounted).
--
Ron Johnson, Jr.
Jefferson LA USA
"I am not surprised, for we live long and are celebrated poopers."
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