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Groups > comp.sys.mac.hardware.misc > #179

Re: Memory lock failed

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On 08/20/2011 07:56 PM, David Empson wrote:
> philo<philo@invalid.not>  wrote:
>
>> On 08/19/2011 03:10 PM, Francois wrote:
>>> I had recently memory problems on my Mac Pro (early 2008), and I had to
>>> replace some 4GB DIMM's to recover my original 24 GB RAM. This Ram
>>> consists now of 4 slots with 2GB ( risers A&  B) and 4 with 4GB ( also
>>> half on A , half on B). The makers are Crucial (2x4 GB) and "elixir" for
>>> the rest. Of course I ran memtest ( in single user mode ) after each
>>> memory change ( there were several). Now ,every time, memtest log said :
>>> "Attempted memory lock... ERROR Memory lock failed - reason unknown
>>> WARNING : Testing with unlocked memory may be slower and less reliable"
>>>
>>> The 3 test sequence was every time successful, and the computer behaves
>>> normally.
>>> Anyway I'm baffled : why is my memory not "lockable" ?
>>> Has this something to see with the placement of the memory sticks on the
>>> risers ?
>>> Thanks for any hint, although that doesn't prevent me to sleep.
>>
>>
>>
>> More than likely you are booting to single mode using the 32bit kernel
>> which cannot address more than 4 gigs of ram.
>
> Not exactly. The 32-bit kernel on Mac OS X cannot directly address more
> than 4 GB at a time, but through the use of PAE it is able to manage up
> to 32 GB of RAM, and selectively access all of it.
>
> You can have 64-bit applications running on Mac OS X with 32-bit kernel,
> and in those conditions the 64-bit applications can directly address
> more than 4 GB of RAM.
>
> The "lock" mechanism used by memtest is very likely to be related to the
> 4 GB directly addressable limit of the 32-bit kernel but I'm not
> familiar enough with that level of detail to explain further.
>


Not a function of being a mac...
it's the same for any 32 bit os  vs 64 bit

very few folks use PAE...
at any rate, I am sure the OP does not have PAE enabled
nor do I know if his h/w supports it or not

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Thread

Memory lock failed Francois <xanrov@numericable.fr> - 2011-08-19 22:10 +0200
  Re: Memory lock failed philo <philo@invalid.not> - 2011-08-20 07:45 -0500
    Re: Memory lock failed Francois <danzas@9online.fr> - 2011-08-20 17:08 +0200
      Re: Memory lock failed philo <philo@invalid.not> - 2011-08-20 16:11 -0500
    Re: Memory lock failed Howard Brazee <howard@brazee.net> - 2011-08-20 18:06 -0600
      Re: Memory lock failed Tom Stiller <tom_stiller@yahoo.com> - 2011-08-20 21:04 -0400
        Re: Memory lock failed Howard Brazee <howard@brazee.net> - 2011-08-21 16:10 -0600
          Re: Memory lock failed Tom Stiller <tom_stiller@yahoo.com> - 2011-08-21 19:04 -0400
    Re: Memory lock failed dempson@actrix.gen.nz (David Empson) - 2011-08-21 12:56 +1200
      Re: Memory lock failed philo <philo@invalid.not> - 2011-08-20 21:37 -0500
        Re: Memory lock failed dempson@actrix.gen.nz (David Empson) - 2011-08-21 17:17 +1200
          Re: Memory lock failed nmassello@yahoo.com (Neill Massello) - 2011-08-21 02:32 -0600
            Re: Memory lock failed dempson@actrix.gen.nz (David Empson) - 2011-08-22 00:38 +1200
              Re: Memory lock failed Tom Stiller <tom_stiller@yahoo.com> - 2011-08-21 09:18 -0400
                Re: Memory lock failed dempson@actrix.gen.nz (David Empson) - 2011-08-22 01:34 +1200
          Re: Memory lock failed philo <philo@invalid.not> - 2011-08-21 07:15 -0500
            Re: Memory lock failed dempson@actrix.gen.nz (David Empson) - 2011-08-22 01:04 +1200
              Re: Memory lock failed philo <philo@invalid.not> - 2011-08-21 08:27 -0500
  Re: Memory lock failed Jolly Roger <jollyroger@pobox.com> - 2011-08-20 15:13 +0000
    Re: Memory lock failed Francois <danzas@9online.fr> - 2011-08-21 10:14 +0200

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