Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

ECC matters

realworldtech.com

Post reply on HN
Print view View original

21–30 of 567 posts

Re: ECC matters

#21

Post by hugey010 »

kensai wrote: post #2

“ECC availability matters a lot - exactly because Intel has been instrumental in killing the whole ECC industry with it's horribly bad market segmentation.” Its. There, I finally corrected Linus Torvalds in something. :))

He uses "do do" instead of "to do" which is a more obvious typo. Linus usually comes across as borderline arrogant, and deservedly so, but not necessarily perfect in his writing. I think it's an effective strategy to communicate his priorities and wrangle smart but easily intimidated folk "do do" what he believes is right!

Re: ECC matters

#22

Post by simias »

londons_explore wrote: post #11

I simply care that my computer executes code perfectly. Let's settle on "one instance of unintended behaviour per hundred years" for that metric. If it needs ECC memory to do that, then fit it with ECC memory. If there are other ways to achieve that (for example deeper dram cells to be more robust to cosmic rays) that's fine too. Just meet the reliability spec - I don't care how.

Then you'll have to pay a huge primer for that privilege. I can assure you that your standard computer components are not rated for century-scale use.

That's why I've always been on the fence with this ECC thing. For servers it's vital because you need stability and security.

For desktops I think that for a long time it was fine without ECC. If I have to chose between having, say, 30% more RAM or avoid a potential crash once a year, I'll probably take the additional RAM.

The problem is that now these problem can be exploited by malicious code instead of just merely happening because of cosmic rays. That's the main argument in favour of ECC IMO, the rest is just a tradeoff to consider.

Re: ECC matters

#23

Post by raverbashing »

simias wrote: post #13
raverbashing wrote: post #4

Earlier quoted context omitted.

Yeah I'm always annoyed with this kind of mistake. Especially as non-native speakers should know better than the native ones (which usually don't give a f.). Now the point about internally doing ECC is an interesting one, could be a way out of this mess. And apparently ECC is more available in AMD land

For a 2nd language speaker making these homophonic mistakes is actually a sign of fluency. It means that you just transcribe a mental flow of words instead of consciously constructing the language. The first time I wrote "your" instead of "you're" in English I thought it was quite a milestone!

> For a 2nd language speaker making these homophonic mistakes is actually a sign of fluency.

I kinda disagree because while the homophony works in (spoken) English in written it stands as a sore thumb. So yeah you will make it if you only heard it but doesn't know the written form.

(And in their native language it's probably two unrelated words, so that might intensify the feeling of wrongness)

Re: ECC matters

#24

Post by raverbashing »

tssva wrote: post #12
raverbashing wrote: post #4

Earlier quoted context omitted.

Yeah I'm always annoyed with this kind of mistake. Especially as non-native speakers should know better than the native ones (which usually don't give a f.). Now the point about internally doing ECC is an interesting one, could be a way out of this mess. And apparently ECC is more available in AMD land

The really annoying thing is that auto correct on mobile device keyboards will often want to incorrectly change "its" to "it's" or vice versa.

Yes, auto-corrects compound the problem.

Re: ECC matters

#25

Post by dijit »

sys_64738 wrote: post #14

ECC memory is predominantly used in servers where failure absolutely must be identified and logged. The desktop market to a lesser extent due to lack of mission critical tasks being run from there.

There are situations though, where you’re working on a document and the documents “save” format is a memory dump. Corruption for things of that type (Adobe RAW for example) would remove data.

It might present itself as a 1pixel colour difference, but it could be more damaging (incorrect finances, in accounting software for example). Software trusts memory; but memory can lie.

That’s dangerous.

Re: ECC matters

#26

Post by simias »

IgorPartola wrote: post #18
eloy wrote: post #5

Earlier quoted context omitted.

He does explain it: > We have decades of odd random kernel oopses that could never be explained and were likely due to bad memory. And if it causes a kernel oops, I can guarantee that there are several orders of magnitude more cases where it just caused a bit-flip that just never ended up being so critical. It might be false, but I think it's a reasonable assumption.

To someone on HN who isn’t familiar with what ECC does that explains nothing about how ECC works and how it could have prevented these situations. Or how often they really happen.

The problem is that, if you don't have ECC to detect the errors, it's very hard to know what exactly caused a random, non-reproducible crash. Especially in kernel mode where there's little memory protection and basically any driver could be writing anywhere at any time.

I can understand Linus's frustration from that point of view: without ECC RAM when you get some super weird crash report where some pointer got corrupted for no apparent reason you can't be sure if it's was just a random bitflip or if it's actually hiding a bigger problem.

Re: ECC matters

#27

Post by dboreham »

You don't need to look at kernel crashes to speculate about bus and memory errors -- just check the logs on a few systems that do have ecc. Pretty soon you'll see correctable errors being reported.

Re: ECC matters

#28

Post by bitcharmer »

phh wrote: post #20

I don't know if ECC is that important, but reliability of RAM (or any storage) feels pretty crazy to me. 128GB being refreshed every second for a month error requires that the per-bit refresh process has a reliability of 99.9999999999999999% to be flawless. Considering we are dealing with quantum effects (which are inherently probabilistic), I wouldn't trust myself to design anything like that. Now back to ECC, I'll…

A system on Earth, at sea level, with 4 GB of RAM has a 96% percent chance of having a bit error in three days without ECC RAM. With ECC RAM, that goes down to 1.67e-10 or about one chance in six billions.

So I'd say ECC is not only important but insanely impactful. There's a reason why many organizations don't even want to hear about getting rigs with non-ECC memory.

Re: ECC matters

#29

Post by ekianjo »

simias wrote: post #9

I used to be pretty skeptical of ECC for consumer-grade hardware, mainly because I felt that I'd always prefer cheaper/more RAM over ECC RAM even if it meant that I'd get a couple of crash every year due to rogue bitflips. For servers it's a different story, but for a desktop I'm fine dealing with some instability for better performance. But these days with the RAM density being so high and bitflipping attacks being…

> no good reason not to switch to ECC everywhere.

Not all CPUs support ECC however.

Re: ECC matters

#30

Post by 1996 »

Linus is absolutely right.

I am trying to get a laptop with dual NVMe (for ZFS) and ECC RAM. I can't get that, at all - even without the other fancy things I would like such as a 4k OLED with pen/touchscreen.

In 2020, even the Dell XPS stopped shipping OLED (goodbye dear 7390!)

I will gladly give my money to anyone who sells AMD laptop with ECC. Hopefully, it will show there's demand for "high end yet non bulky laptops"

Post reply on HN