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Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?


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Old 08-15-2009, 06:06 PM   #1
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Bad RAM or PAE?

I have a remote server that is reporting 8GB of RAM when it should have 12GB. I did recompile the kernel with the realtime kernel. I'm pretty sure I added PAE support. Could this be bad RAM or would a non-PAE kernel report 8GB from 12GB?
Old 08-15-2009, 06:23 PM   #2
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If it's a 32bit machine, the options for memory include something like <4GB, 4GB, or 64GB; the first two options would/should not even report 8GB, so chances are good that you've got the 64GB model selected. If this is the case however, it *should* report all 12GB.

If the machine is 64bit, then this is irrelevant; there are no such PAE memory options.

According to Wikipedia however, the amount of usable/available memory when using PAE for a 32bit machine is also subject to the CPU in use on the machine. Not every CPU necessarily supports 100% the PAE extended addressing.

As for RT-ness of the kernel, I cannot comment one way or the other; I have absolutely no experience on that front, so I don't know if it affects memory addressing or not (but I'd think not..).

Old 08-15-2009, 06:25 PM   #3
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If you are seeing 8 Gig (on a 32-bit system), PAE is active.
Old 08-15-2009, 06:43 PM   #4
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Great, now I need to get someone to troubleshoot some RAM at my colo

Thanks all.


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