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For a brief period, the Windows kernel tried to deal with gamma rays

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Re: For a brief period, the Windows kernel tried to deal with gamma rays

#41

Post by bgirard »

amichal wrote: post #35
detaro wrote: post #31

Earlier quoted context omitted.

I think the article gives good reasons to believe they are not typos, why do you think otherwise?

While i like the sibling comment's network errors answer better then mine I didn't see any reasoning other then a unfounded statement[1] in the article or on a quick skim for "typo" in the referenced whitepaper: [1] "These requests were not typos or other manually entered URLs"

Here's a better quote: "There are many frequently resolved domains that few people type or know."

There's a lot more details in the article.

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#42

Post by eli »

amichal wrote: post #35
detaro wrote: post #31

Earlier quoted context omitted.

I think the article gives good reasons to believe they are not typos, why do you think otherwise?

While i like the sibling comment's network errors answer better then mine I didn't see any reasoning other then a unfounded statement[1] in the article or on a quick skim for "typo" in the referenced whitepaper: [1] "These requests were not typos or other manually entered URLs"

"All of these requests used only four domains in the HTTP Host header, as shown in Table 4. Three out of four domains contain more than one bit error, ruling out a simple mistype of fbbdn.net for fbcdn.net. "

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#43

Post by sannee »

andikleen3 wrote: post #34
spullara wrote: post #19

If you don't believe in bit flips, try this! http://dinaburg.org/bitsquatting.html I did that for a bit on cloudfront.net and got dozens of them in a short amount of time.

I maintain a tool that reports errors on Linux systems with ECC memory, and also a website describing the tool ( http://mcelog.org ). I wrote about patterns in the access logs correlated to time some time ago in my blog: http://halobates.de/blog/p/181

> I wonder if it’s possible to detect solar flares in these logs. Need to find a good data source for them. Are there any other events generating lots of radiation that may affect servers?

Cosmic ray showers [1] potentially. My prediction is that there should be "clusters" of bit errors every few minutes or so (given sufficient amount of servers...).

I was talking to a sysadmin at a local company running a few thousand servers about getting their ECC error logs in order to look for these, but scraping them apparently wasn't trivially managable for them.

[1] - https://en.wikipedia.org/wiki/Air_shower_(physics)

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#44

Post by tjoff »

asveikau wrote: post #40
worldlinx wrote: post #18

Earlier quoted context omitted.

Unless you know what you are doing, you might want to delete that. Probably goes against the NDA you've signed, no?

It's pretty obvious that when people at Microsoft say "processor vendor" it's a euphemism for "Intel". Not as true anymore now that they support arm but... Still kinda true.

You do know that the 64 bit version of Windows XP was made for AMD processors before intel had any.

We also had Transmeta. I bet all of them have some kinks just as different models from the same vendor have different bugs etc. that require special handling.

Meltdown/Spectre is just a recent and very visible artifact that would demonstrate this.

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#45

Post by rubenbe »

Bit flips are real. I used to see them on my (admittedly low end) webserver. Eg. There were occasional errors like "myOfunction not found". A quick glance on a ASCII table shows that the original function name "my_function" is indeed one bitflip away (0x4F vs 0x5F)

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#46

Post by planteen »

21 wrote: post #27
nategri wrote: post #15

A pedantic point (good thing I'm on HN), but I wonder if they didn't actually mean muons and not gamma rays?

Apparently 95% of "bit flipping cosmic rays" are neutrons: > At the Earth's surface approximately 95% of the particles capable of causing soft errors are energetic neutrons with the remainder composed of protons and pions. https://en.wikipedia.org/wiki/Soft_error#Cosmic_rays_creatin...

Sounds about right. I've been a part of a radiation test giving a SoC gamma exposure for total irradiating dose measurement. I didn't see a single upset the whole test.

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#47

Post by notacoward »

blattimwind wrote: post #10
notacoward wrote: post #4

To answer the question in the OP: yes, the processor cache might be more susceptible than RAM, if the RAM is ECC. I've heard many stories about bit-flips causing serious problems at higher-elevation sites. Apparently a major installation at either NCAR or UCAR was delayed by a month fighting such problems. While I haven't actually confirmed any of these stories first hand, I've heard enough to believe that a little p…

Internal data buses and caches are typically ECC'd. In fact, DRAM and the memory bus are most likely the only non-ECC parts in desktop computers.

It would definitely be interesting to know more of the context around this code in Windows - when it existed, and which processor models would enable it. I'm pretty sure some of the x86-compatible processors made by several vendors over a couple of decades weren't ECC all the way through.

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#48

Post by mattnewton »

tjoff wrote: post #29
spullara wrote: post #19

If you don't believe in bit flips, try this! http://dinaburg.org/bitsquatting.html I did that for a bit on cloudfront.net and got dozens of them in a short amount of time.

Bit flips in network surely is many orders of magnitude worse than in cache/memory bit flips? And I doubt it has to do with gamma rays. Those with poor or long distance DSL do see a big increase in errors. And while hopefully getting rarer now home routers could easily overheat and introduce errors as soon as they saw more than usual traffic. We recently had issues with the power supply for our router and it also cau…

The end of gp’s Article points to some work by a verisign engineer that put the network probability very low. So my interpretation was these but flips were happening on device before the network stack was dispatched at a url.

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#49

Post by datenwolf »

Invalidating the caches is kind of a cringe inducing approach on this (actual) problem. Especially in HPC radiation related single event upsets have become a real problem. If you do the math, all the silicon area devoted to memory (DRAM, caches, registers) adds up, and what you've got is essentially particle detector.

Compared to the effective volume of a purpose designed one (ATLAS, CMS, Super Kaminokade, etc.) rather small, but a particle detector nevertheless.

A couple of months / years ago, there was an article (also linked here on HN, IIRC) that did a few back of the envelope calculations regarding expected event rates. IIRC it was something on the order of 1 event per day per 10^12 transistors. (EDIT: not the one I thought of but blows the same horn: http://energysfe.ufsc.br/slides/Paolo-Rech-260917.pdf )

Also radiation hardened software has been researched (and still is). Essentially the idea is to not only have redundant, error correcting memory, but also redundant, error correcting computation. NASA has some publications on that. e.g. https://ti.arc.nasa.gov/m/pub-archive/1075h/1075%20(Mehlitz)...

Re: For a brief period, the Windows kernel tried to deal with gamma rays

#50

Post by asveikau »

tjoff wrote: post #44
asveikau wrote: post #40

Earlier quoted context omitted.

It's pretty obvious that when people at Microsoft say "processor vendor" it's a euphemism for "Intel". Not as true anymore now that they support arm but... Still kinda true.

You do know that the 64 bit version of Windows XP was made for AMD processors before intel had any. We also had Transmeta. I bet all of them have some kinks just as different models from the same vendor have different bugs etc. that require special handling. Meltdown/Spectre is just a recent and very visible artifact that would demonstrate this.

Yeah I know. But I think at MS they work closely with Intel and think of other vendors as not as important.

I did work there too, and to be clear, did not witness anything like this. Just a personal opinion/hunch.

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