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

[Bill Davidsen]

Roberto Ragusa wrote:
> Kevin J. Cummings wrote:
>> On 12/17/2009 12:51 PM, Mark Ryden wrote:
> 
>>> 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.
> 
> And the PAE kernel will be installed by default.
> So the 32 bit Fedora could be considered without limit too.
> 
IIRC 36 bits, or 64GB, reasonable design for a number chosen decades ago. Still 
a reasonable size for anything but servers, most motherboards support 16-24GB 
max, and only half of that if you use affordable 2GB memory instead of 4GB.

The PAE kernel allows use of the NX bit, to prevent execution of non-program 
memory areas.

-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot