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I have just installed some new RAM (2x1GB, 667, sticks from 2x512MB, 533, sticks) into an old system (perfectly valid), and all was working fine, until now.

I have been having some issues when the computer (a debian box) would crash for no apparent reason, and due to its consistent behavior at certain file sizes being accessed after a time (usually about 1.6GB) it would crash.

I have just installed memtest86+ on the system, and after running it for just a few seconds (now been running all night), it is telling be that the memory at 615-616MB and 1637-1638MB are acting erroneously.

Now, instead of removing the new RAM and returning the old, or buying some new RAM all together, is it possible to instruct the memory component of debian to ignore these regions (I don't mind sacrificing a few MB's of RAM for the bonus of another GB or less) so my system can continue to operate normally?

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1 Answer 1

You can use the memmap kernel command line option. Here's the relevant bit of the documentation:

memmap=nn[KMG]$ss[KMG]

  [KNL,ACPI] Mark specific memory as reserved.
  Region of memory to be used, from ss to ss+nn.
  Example: Exclude memory from 0x18690000-0x1869ffff
          memmap=64K$0x18690000
          or
          memmap=0x10000$0x18690000

Full kernel boot parameters doc: https://www.kernel.org/doc/Documentation/kernel-parameters.txt

That said, it's probably a bad idea as buggy RAM sticks may get worse with time, so you may have other parts of memory that will need blacklisting

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Just been searching on google, but can't find where the kernel parameters are stored. The only reference I found was in /usr/src/linux, but upon checking, my system only has /usr/src, and after that, it's empty –  cgoddard Mar 10 '13 at 4:30
    
That's going to depend on the distro and on the boot loader you use. Arch Linux has a good guide. See this: wiki.archlinux.org/index.php/Kernel_parameters#GRUB for a method that involves one shot parameter passing with GRUB –  Frederik Deweerdt Mar 10 '13 at 4:44

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