faq

系统启动时检测内存状况的软件C代码

  settings, correct them if they don't and run memtest again
  
  Ok, you have all the settings correctly set and you're still getting errors.
  Well of course a very likely cause are the memory modules and the logical
  course of action is to look into them further.

  If you are well stocked, have a few other machines at your disposal, or just
  want to spend the cash for some new modules the best way to test if the
  cause are your memory modules is just to replace them and test again. If you
  are less fortunate though there is still something you can do.

  If you have more then one module in your system, test them one by one, if
  one is consistently giving errors and another is consistently showing no
  errors it's a pretty good bet that the module giving the errors is simply
  defective. To exclude the possibility that a defective slot is throwing your
  results, use the same slot to test each different module.
  
  If each module by itself shows no errors, but when you place two or more
  modules into the machine at the same time you do get errors, you are most
  likely stuck with a compatibility issue and unfortunately there isn't a
  whole lot you can do about it. Be sure to check your computer/motherboard
  manual to see if the setup you are trying is allowed, some boards require
  special restrictions in the sizes of modules, the order of modules, the
  placement of double sided and single sides modules and more of such things.

  If you have only one module in your system, or all modules are giving
  errors, there are only very few options left. The only thing you can do
  really is to try the module(s) in another slot. Finally simply try out
  different orders of the memory modules, although your manual might not
  mention anything on the matter sometimes there simply exist timing or other
  issues which can be resolved by changing the order of your modules.  And of
  course test each slot by putting a single module into that slot and running
  memtest on it.

  In the end if you still have not been able to localize the problem you will
  have to find a replacement module to establish whether the problem lies in
  your modules. See if you can borrow a module from someone else.

  When you have replaced the memory by new memory and the errors still
  persist, first check if you can rule out any compatibility issues or timing
  issues. If you are sure the memory should work in the system the cause of
  the errors must obviously lie someplace else in the system.
  
  The only way to find out where, is by trial and error really. Simply start
  replacing and/or removing parts of your computer one by one, running memtest
  each time you changed anything, until the errors are resolved.

- I'm getting errors in test #x, what doest that mean?

  Interpreting memtest results is as scientific an endeavour as testing
  whether a person is a witch by the methods used in Monty Python's Holy
  Grail. In short, don't even start, it's not going to get you anywhere. Just
  interpret any error as you should any other and use the methods descibed in
  the previous question to determine the cause.

- I'm getting errors in test #5 and/or #8 and have read a lot about it.

  Yes there are just about enough discussions on the topic to fill a book, but
  it all boils down to the answer given above. The only thing that can be said
  is that many a times, when memory latencies are incorrectly set in the BIOS
  you will experience errors in test #5 and #8. (Though #8 does not exist
  anymore as of version 1.40 and might be reinstated as a different test in a
  later version.) This does however NOT mean that errors in these tests are
  always the cause of incorrect settings, your memory might just as well be
  defective.

- I'm getting errors in memtest on one machine, but not when I put the same
  memory in another, what does that mean?

  It can mean one of two things:
    - The machine that is giving the errors is defective. Errors don't just
      orginate from the memory module itself, but can also be caused by
      defects in the cpu, chipset, motherboard, PSU and even by timing issues
      introduced by any other component in the machine.
    - The machine giving the errors is imposing stricter timing than the other
      which the memory module simply can't cope with. If the module should
      work with the machine according to its specifications then it most
      likely is defective.

- Which memory is tested?

  As much as possible of the system memory is tested. Unfortunately memtest86+
  can usually not test all of the memory. The reason for this is that todays
  processors have become so complex that they require a small amount of memory
  to keep accounting data of the processor state. If memtest were to write
  over these areas the state of the processor becomes invalid and it's
  behaviour unpredictable. Alas it is also impossible to relocate these areas
  in the memory.

  This means that a small area of your memory can not be tested by memtest. If
  this part of the memory is defective you will know soon enough though as the
  processor, or parts of the processor simply won't work correctly if this
  part of your memory is defective. Do realise though that in very rare cases
  memtest will show no errors even though the module is defective, not because
  memtest can't detect the error, but because memtest can't test the area the
  error is located in.

- When I select BIOS-ALL I get many errors / my machine crashes.

  This is normal. With todays computers this option should never be selected.
  See the previous question about the reason for the errors.

- I want to use memtest on a multiboot CD, how do I do this?

  This is of course very dependent on which boot loader you use for your CD.
  Below is a description of how to set up a multiboot CD including memtest+
  with isolinux, if you have experience with any other bootloader(s) please
  consider writing a small description of using memtest with that bootloader
  for the FAQ.

  -isolinux
    
    For general instructions on how to make a bootable CD with isolinux see
    the syslinux website and the manual. What you need to do to get memtest
    working is as follows.

    Download the Pre-Compiled Bootable Binary, the .gz if you are working
    under linux, the .zip if you are working under windows. Unpack the file
    from the package and rename it to an 8.3 filename with an extension other
    than .bin, renaming to memtest. (without an extension) is a good choice.

    Put the file somewhere in your CD directory structure, for example in
    images/memtest and edit your config file to include the following:

    label memtest
        kernel /images/memtest

    If you want to boot memtest automatically insert or change a line at the
    top to:

    default memtest

    If you want to display a prompt from which you can start memtest add or
    change the lines at the top to: (Change the timeout to suit your needs)

    prompt 1
    timeout 200

- If memtest86+ shows no errors does that mean my memory is not defective?

  Of course no answers are definitive, no matter how good memtest86+ will
  eventually become there is always the possibility that a particular type of
  error will go unnoticed. As long as you are having no problems with the
  system it will be pretty safe to say that the modules are good. If you are
  having problems with the system however you will just have to check by trial
  and error, ie swapping the modules for new ones and/or testing with modules
  of a different brand/type.

- When I run install.bat it doesn't write anything to floppy.

  You most likely have unpacked the memtest+-1.xx.floppy.zip file into a
  folder with a long pathname and/or containing + and - signs. It seems
  rawrite doesn't like that. Just move the files you unpacked to a directory
  like c:\memtest and execure it from there.