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系统启动时检测内存状况的软件C代码

Enhancements in v3.1 (11/Mar/2004)

   Added processor detection for newer AMD processors.

   Added new "Bit Fade" extended test.

   Fixed a complile time bug with gcc version 3.x.

   E7500 memory controller ECC support

   Added support for 16bit ECC syndromes

   Option to keep the serial port baud rate of the boot loader


Enhancements in v3.0 (22/May/2002) Provided by Eric Biederman

   Testing of more than 2gb of memory is at last fixed (tested with 6Gb)

   The infrastructure is to poll ecc error reporting chipset regisets,
   and the support has been done for some chipsets.

   Uses dynamic relocation information records to make itself PIC
   instead of requiring 2 copies of memtest86 in the binary.

   The serial console code does not do redundant writes to the serial port
   Very little slow down at 9600 baud.

   You can press ^l or just l to get a screen refresh, when you are
   connecting and unconnecting a serial cable.

   Netbooting is working again

   LinuxBIOS support (To get the memory size)

   Many bugfixes and code cleanup.

Enhancements in v2.9 (29/Feb/2002)

   The memory sizing code has been completely rewritten.  By default
   Memtest86 gets a memory map from the BIOS that is now used to find 
   available memory. A new online configuration option provides three
   choices for how memory will be sized, including the old "probe" method.
   The default mode generally will not test all of memory, but should be more
   stable. See the "Memory Sizing" section for details.

   Testing of more than 2gb of memory should now work.  A number of bugs
   were found and corrected that prevented testing above 2gb.  Testing
   with more than 2gb has been limited and there could be problems with a
   full 4gb of memory.

   Memory is divided into segments for testing.  This allow for frequent
   progress updates and responsiveness to interactive commands.  The
   memory segment size has been increased from 8 to 32mb.  This should
   improve testing effectivness but progress reports will be less frequent.

   Minor bug fixes.

Enhancements in v2.8 (18/Oct/2001)
   Eric Biederman reworked the build process making it far simpler and also
   to produce a network bootable ELF image.

   Re-wrote the memory and cache speed detection code.  Previously the
   reported numbers were inaccurate for intel CPU's and completely wrong
   for Athlon/Duron CPU's.

   By default the serial console is disabled since this was slowing
   down testing.

   Added CPU detection for Pentium 4.

   
Enhancements in v2.7 (12/Jul/2001)
   Expanded workaround for errors caused by BIOS USB keyboard support to
   include test #5.

   Re-worked L1 / L2 cache detection code to provide clearer reporting.

   Fixed an obvious bug in the computation of cache and memory speeds.

   Changed on-line menu to stay in the menu between option selections.

   Fixed bugs in the test restart and redraw code.

   Adjusted code size to fix compilation problems with RedHat 7.1.

   Misc updates to the documentation.

Enhancements in v2.6 (25/May/2001)
   Added workaround for errors caused by BIOS USB keyboard support.

   Fixed problems with reporting of 1 GHZ + processor speeds.

   Fixed Duron cache detection.

   Added screen buffer so that menus will work correctly from a serial
   console.

   The Memtest86 image is now built in ELF format.

Enhancements in v2.5 (14/Dec/00)
   Enhanced CPU and cache detection to correctly identify Duron CPU
   and K6-III 1MB cache.

   Added code to report cache-able memory size.

   Added limited support for parity memory.

   Support was added to allow use of on-line commands from a serial
   port.

   Dropped option for changing refresh rates.  This was not useful
   and did not work on newer motherboards.

   Improved fatal exception reporting to include a register and stack
   dump.

   The pass number is now displayed in the error report.

   Fixed a bug that crashed the test when selecting one of the extended
   tests.

Enhancements in v2.4
   The error report format was reworked for better clarity and now
   includes a decimal address in megabytes.

   A new memory move test was added (from Robert Redelmeier's CPU-Burn)

   The test sequence and iterations were modified.

   Fixed scrolling problems with the BadRAM patterns.


Enhancements in v2.3
   A progress meter was added to replace the spinner and dots.

   Measurement and reporting of memory and cache performance  
   was added.

   Support for creating BadRAM patterns was added.

   All of the test routines were rewritten in assembler to
   improve both test performance and speed.

   The screen layout was reworked to hopefully be more readable.

   An error summary option was added to the online commands.


Enhancements in v2.2
   Added two new address tests

   Added an on-line command for setting test address range

   Optimized test code for faster execution (-O3, -funroll-loops and
	-fomit-frame-pointer)

   Added and elapsed time counter.

   Adjusted menu options for better consistency


Enhancements in v2.1
   Fixed a bug in the CPU detection that caused the test to
   hang or crash with some 486 and Cryrix CPU's

   Added CPU detection for Cyrix CPU's

   Extended and improved CPU detection for Intel and AMD CPU's

   Added a compile time option (BIOS_MEMSZ) for obtaining the last
   memory address from the BIOS.  This should fix problems with memory
   sizing on certain motherboards.  This option is not enabled by default.
   It may be enabled be default in a future release.

Enhancements in v2.0
   Added new Modulo-20 test algorithm.

   Added a 32 bit shifting pattern to the moving inversions algorithm.

   Created test sections to specify algorithm, pattern and caching.

   Improved test progress indicators.

   Created  popup menus for configuration.

   Added menu for test selection.

   Added CPU and cache identification.

   Added a "bail out" feature to quit the current test when it does not
   fit the test selection parameters.

   Re-arranged the screen layout and colors.

   Created local include files for I/O and serial interface definitions
   rather than using the sometimes incompatible system include files. 

   Broke up the "C" source code into four separate source modules.

Enhancements in v1.5
   Some additional changes were made to fix obscure memory sizing
   problems.

   The 4 bit wide data pattern was increased to 8 bits since 8 bit
   wide memory chips are becoming more common.

   A new test algorithm was added to improve detection of data
   pattern sensitive errors. 


Enhancements in v1.4
   Changes to the memory sizing code to avoid problems with some
   motherboards where memtest would find more memory than actually
   exists.

   Added support for a console serial port. (thanks to Doug Sisk)

   On-line commands are now available for configuring Memtest86 on
   the fly (see On-line Commands).
	

Enhancements in v1.3
   Scrolling of memory errors is now provided.  Previously, only one screen
   of error information was displayed.

   Memtest86 can now be booted from any disk via lilo.

   Testing of up to 4gb of memory has been fixed is now enabled by default.
   This capability was clearly broken in v1.2a and should work correctly
   now but has not been fully tested (4gb PC's are a bit rare).

   The maximum memory size supported by the motherboard is now being
   calculated correctly.  In previous versions there were cases where not
   all of memory would be tested and the maximum memory size supported
   was incorrect.

   For some types of failures the good and bad values were reported to be
   same with an Xor value of 0.  This has been fixed by retaining the data
   read from memory and not re-reading the bad data in the error reporting
   routine.

   APM (advanced power management) is now disabled by Memtest86.  This
   keeps the screen from blanking while the test is running.

   Problems with enabling & disabling cache on some motherboards have been
   corrected.


17) Donations
=============
With considerable reluctance I am resorting to a low key solicitation for
donations.  It never has been my intent to profit from this program and I am
pleased that Memtest86 has been helpful.  However, the time required to
support this program has grown significantly.  I also have the modest
cost of hosting this web-site that I would like to recover.  So if you find
Memtest86 useful and you feel inclined to make a small PayPal donation please
do so.  Use "[e-mail]" for the recipient.


18) Acknowledgments
===================
Memtest86 was developed by Chris Brady with the resources and assistance
listed below:

- The initial versions of the source files bootsect.S, setup.S, head.S and
  build.c are from the Linux 1.2.1 kernel and have been heavily modified.

- Doug Sisk provided code to support a console connected via a serial port.

- Code to create BadRAM patterns was provided by Rick van Rein.

- Tests 5 and 8 are based on Robert Redelmeier's burnBX test.

- Screen buffer code was provided by Jani Averbach.

- Eric Biederman provided all of the feature content for version 3.0
  plus many bugfixes and significant code cleanup.

- Major enhancements to hardware detection and reporting in version 3.2
  provided by Samuel Demeulemeester (from Memtest86+ v1.11).