physical RAM restriction in Fedora 12 (32 bit and 64 bit)

[Kevin J. Cummings]

On 12/17/2009 12:51 PM, Mark Ryden wrote:
> Hello,
>   AFAIK, in windows 7, **32 bit**, there is a limit of 3GB physical
> RAM which can be recognized by the operating system.
> This means that if you have 4GB of RAM, only 3 will be used.

This is usually a BIOS limitation.

> My question is:
> 1) In Fedora 12 32 bit default installation , does the kernel knows
> more than 3 GB of RAM ? what is the limit ?

The same.  It uses what the BIOS tell it is available, unless you run a
PAE kernel.  The Physical Address Extensions allow you to address the
full amount of your RAM.

> 2) In Fedora 12 64 bit default installation , does the kernel knows
> more than 3 GB of RAM ? what is the limit ?

64-bit does not have the artificial limitation (the actual limit is
*much* higher than you can currently put in a machine today) that 32-bit
does.  You should see the same with Windows too.

> Rgs,
> Mark

-- 
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us
Registered Linux User #1232 (http://counter.li.org)