[ale] Max RAM?

[JK]

Denny Chambers wrote:

> If I remember correctly the stock kernels with most distributions are 
> not compiled to support 64GB, you have to set a flag in the config file 
> and recompile the kernel to get the 64 GB memory usage. Is this still true?

Probably. The name of the option is CONFIG_HIGHMEM_64GB, I think,
but I don't have a kernel config to look at to confirm at the
moment.

-- JK

> Denny
> 
> JK wrote:
> 
>>Greg Freemyer wrote:
>>
>>  
>>
>>>All,
>>>
>>>I need to buy a server in the next several months that may need a lot of RAM.
>>>
>>>I thought x86 machines had a limit of 4GB, but then I see the HP
>>>ProLiant DL380 can have up to 32GB max.
>>>
>>>Does the CPU model effect it?  AMD? Intel? Xeon? Pentium 4?
>>>
>>>Can someone explain what the restrictions are, or point me at a good url.
>>>    
>>
>>Intel added a hack called "Physical Addressing Extensions" to
>>later Pentium models.  This hack allows the processor
>>to address up to 64GB of RAM via bank-switching, though
>>only 4GB is visible at any particular time.
>>
>>Here's a M$ page about PAE support for Windows:
>>
>>http://support.microsoft.com/kb/268363
>>
>>Linux also supports PAE (as of kernel 2.4 at least),
>>and can address all 64GB of physical RAM, if
>>it's present.  The virtual address space for any particular
>>process, however, is still limited to 3GB (Linux
>>reserves 1GB [normally] of virtual space for the kernel).
>>
>>-- JK
>>
>>_______________________________________________
>>Ale mailing list
>>Ale at ale.org
>>http://www.ale.org/mailman/listinfo/ale
>>
>>
>>  
> 
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://www.ale.org/mailman/listinfo/ale
> 
>