1March 2008
2Jan-Simon Moeller, dl9pf@gmx.de
3
4
5How to deal with bad memory e.g. reported by memtest86+ ?
6#########################################################
7
8There are three possibilities I know of:
9
101) Reinsert/swap the memory modules
11
122) Buy new modules (best!) or try to exchange the memory
13   if you have spare-parts
14
153) Use BadRAM or memmap
16
17This Howto is about number 3) .
18
19
20BadRAM
21######
22BadRAM is the actively developed and available as kernel-patch
23here:  http://rick.vanrein.org/linux/badram/
24
25For more details see the BadRAM documentation.
26
27memmap
28######
29
30memmap is already in the kernel and usable as kernel-parameter at
31boot-time.  Its syntax is slightly strange and you may need to
32calculate the values by yourself!
33
34Syntax to exclude a memory area (see kernel-parameters.txt for details):
35memmap=<size>$<address>
36
37Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 and
38         some others. All had 0x1869xxxx in common, so I chose a pattern of
39         0x18690000,0xffff0000.
40
41With the numbers of the example above:
42memmap=64K$0x18690000
43 or
44memmap=0x10000$0x18690000
45
46