[kwlug-disc] 64 bit install

john at netdirect.ca john at netdirect.ca
Thu Sep 24 14:25:32 EDT 2009

kwlug-disc-bounces at kwlug.org wrote on 09/24/2009 01:33:48 PM:
> From: "Insurance Squared Inc." <gcooke at insurancesquared.com>
> To run 64 bit installs of linux, do I need 64 bit hardware?  I tried to 
> install on a Xeon machine and it objected that the hardware was only 32 
> bit.  (It's a 32 bit machine for the same reason I drive a Chrysler. 
> All I could afford at the time :) ).
> In the same vein, if I install a 32 bit install of say Mandriva on a 
> machine with 8 gigs of ram, would one expect that the kernel being 
> installed will address all 8 gigs?  i.e. do distro installs check for 
> that stuff automatically these days?

Like Rashkae said your kernel must support PAE.

Keep in mind that there are limitations when using PAE. Each process can 
only access 4GB of memory but it is transparent to the process. A 32 bit 
application can access more memory than the 4GB if it uses special 
extensions for accessing the memory. This isn't transparent.

So if you only have one memory hungry process on this server you may find 
that it won't use all the 8GB. If you have many memory hungry processes 
each can have their own 4GB space.

I'm not sure, but I think that the kernel can use any remaining memory for 
buffer and page cache so the 8GB won't go to waste if not used by an 

John Van Ostrand
Net Direct Inc.
564 Weber St. N. Unit 12
Waterloo, ON N2L 5C6
john at netdirect.ca
Ph: 866-883-1172
Linux Solutions / IBM Hardware
Fx: 519-883-8533

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