Memtest86+ on Intel Mac

As the name suggests, Memtest86+ is a very thorough memory testing program for x86 computers. With slight modification of a patch for the Grub bootloader, it will run on Intel Macs.

Here is a patch against memtest86+ 1.70, or a prebuilt .iso image. I've be interested to hear how it works on other Macs, especially those with large amounts of RAM.

Updated 9 July 2007 to skip the bottom ~1.2MB of memory to avoid spurious errors.

Caveats:

• Keyboards don't seem to work with Memtest86+ on Intel Macs. Supposedly booting via rEFIt might help, though it didn't work for me. I can't see any obvious way that Memtest86+ differs in its keyboard routines to say a Linux kernel, which works fine. Anyone got suggestions?
• While it seems to work fine on my machine, I provide absolutely no warranty that this software is safe to run (as per the GPL).
• This version has been modified to skip the first ~1.2MB of memory. Apple's Boot Camp BIOS emulation doesn't mark this memory as unusable, but it seems to be used for system purposes (the numlock LED will blink, and you'll get spurious errors). The -1 patch didn't skip that, the -2 patch does — this should make the newer version more useful.
• The memory speeds are wrong and vary each run. These are purely informational, so it doesn't matter.

Proof! It worked first time:

9 March 2007
Matt Johnston <matt at ucc.asn.au>

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