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Re: why linux can't see my memory

If you have a memory hole, chances are there wouldn't be a BIOS option to help. It has to do with the way that memory-mapped i/o is handled with some families of chips and their associated motherboards.
For example, I have two older servers - fully loaded with 4Gig of RAM (as I said, older servers) - but no way, no how does the system see more than 3G. The other 1G is taken up by memory mapped i/o space. It's a hardware design issue, not a BIOS issue. (For reference: P4 640 processor, Supermicro P8SCT motherboard).
In addition to the reference I sent earlier, this sort of describes the issue: http://en.wikipedia.org/wiki/3_GB_barrier 
and this: http://www.dansdata.com/askdan00015.htm
If you do some googling, you'll also find an Intel design note that's the definitive description of the issue (I can't seem to find it right now)
Some BIOSs support "memory hole remapping," but others don't - and that assumes the underlying chipset and motherboard will support it. A lot don't.
Of course this might not be the problem you're seeing. What CPU, chipset, motherboard, and BIOS are you running? 

Long Wind wrote:

Thanks for your reply!
I have google and someone says changing BIOS option about memory hole

I search my BIOS, can't find such option,  no luck
On Sun, Jan 5, 2014 at 9:00 AM, Miles Fidelman <mfidelman@meetinghouse.net <mailto:mfidelman@meetinghouse.net>> wrote: 

    Zenaan Harkness wrote:

        On 1/5/14, Long Wind <longwind2009@gmail.com
        <mailto:longwind2009@gmail.com>> wrote:

            BIOS see all memory and Windows XP can run
            Yes, memory test OK after the memtest probe method

            I have a woody install CD
            I try to boot bf24, if fails (the default kernel also fail)

            I have no live CD, but I have plug a hard disk with wheezy
            I don't believe it make difference


    Are you running on an older motherboard?  It could be a memory
    hole problem.  See http://en.wikipedia.org/wiki/PCI_hole

    Miles Fidelman
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--
In theory, there is no difference between theory and practice.
In practice, there is.   .... Yogi Berra
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