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[Gams]

Hi guys, Im in the process of building a new computer and have been looking forward to getting back into DF as my last laptop could barely sustain a fort past a year or two. Iv run a memory diagnostic tool memtest86 and keep getting errors on test 13, and have been reading about the causes of these errors and thought they might be something of particular interest to DF players.

Memtest86 V6 was released on the 13th of feb this year, the biggest inclusion in v6 is test 13 a 'row hammer' test. This test was added in response to a study released last year by Yoongu Kim; Flipping Bits in Memory Without Accessing Them: An Experimental Study of DRAM Disturbance Errors.

https://www.ece.cmu.edu/~safari/pubs/kim-isca14.pdf
http://users.ece.cmu.edu/~omutlu/pub/dram-row-hammer_kim_talk_isca14.pdf

In short due to the compact design of modern ram rapid accessing of memory rows can cause disturbance errors where cells in adjacent memory rows are flipped.

For the most part this error will not be a factor as the rapid accessing of memory needed to readily causes such errors is not something that most people will experience in day to day usage. However the reason I am posting here is that the system requirements page on the DF wiki states "Dwarf Fortress works the RAM every single frame for every single creature, every single item, every single piece of liquid, the temperature of every tile". I suspect that the way DF uses memory could cause these errors contributing to the death of forts. I am not a expert in this and have only the suspicions based on what i have read, and there is every chance that I am completely wrong.

http://www.passmark.com/forum/showthread.php?5077-How-to-relate-to-errors-in-Hammer-Test-13
-a related post from the passmark forum, the people who make memtest86 for anyone still interested at this point.

Thank you for your time and if anyone knows more I am eager to hear other peoples opinions about this.

[Dirst]

I wouldn't worry about DF accidentally flipping bits with the rowhammer vulnerability because that requires a sustained series of memory operations that is the largest size possible to be bundled together in a single memory refresh cycle, while preventing the computer from loading this frequently-accessed memory into a cache.  DF doesn't write to RAM that much, but more importantly it doesn't disable caching.