[olug] Allocating 3GB of memory for the JVM?

Luke -Jr luke at dashjr.org
Tue Feb 12 13:25:13 UTC 2008

On Tuesday 12 February 2008, Rob Townley wrote:
> Following Sean Kelly's link.   With Physical Address Extensions, a 32 bit
> OS can address 36 bits / 64GigaBytes of RAM.  x86-32 with PAE.
> http://en.wikipedia.org/wiki/Physical_Address_Extension
> Which reminds one of memory addressing in DOS - ugly. There is a
> performance hit because it has to map the ram above 4GB differently.    
> However, since PAE has been in CPUs for more than a decade, it should not
> be too bad. Search through /proc/cpuinfo for pae to see if your CPU
> supports it.  I had a problem with VMware not seeming to support it.  Since
> pae/highmem=64gb was compiled into the Ubuntu server cd, the vmware guest
> would not boot. Apparently, some mobile pentiums don't support it by
> default either.

Even with PAE, I'm pretty sure processes are limited to 3 GB RAM still.

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