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I've seen many ECC log lines on machines before, my wifi routers have ECC memory and they have seen at least one fault each. It isn't a one in a million sort o

I've seen many ECC log lines on machines before, my wifi routers have ECC memory and they have seen at least one fault each. It isn't a one in a million sort of risk, it's just that most systems don't run with ECC, and maybe that bit flip just causes a crash or instability that's chalked up to software bugs. Especially as memory densities continue to skyrocket I would expect to see errors becoming extremely common place. It's some sort of variation of the Toupee Fallacy, you aren't aware of the frequency of bit errors because you have absolutely no way of knowing when they happen, and what "random" errors were caused by them.

colechristensen 4y ago
It’s not that errors don’t happen it’s that they are rare and the surface area of them affecting something important in an important way are incredibly rare. I don’t care about triggering an occasional bug or a bit flip in a video stream, these things are inconsequential. If a bit gets flipped in a photo it’ll be a very slightly different photo. A piece of text will be slightly different… if either had the luck to be in memory ready to write when hit, in dozens of gigabytes of memory. The most likely consequence of a bit flip is nothing at all happening because it hit unallocated memory. The next most likely consequence is nothing as it hit a piece of program memory that has no effect on operation and gets overwritten in moments. ECC zealots are really excited about preventing something that just doesn’t happen all that often: actual data corruption with permanent significant effects.
- RL_Quine 4y ago
  My point was that you don't know when corruption has had an effect, because you're eschewing a method of detecting it.
matheusmoreira 4y ago
> my wifi routers have ECC memory This is really weird. How come even routers have ECC memory while our actual computers don't? Why can't all memory just be ECC memory? I don't even see the point of non-ECC memory. Everything has error correction built-in: hard drives, SSDs, even optical media. Yet RAM doesn't?
- adrian_b 4y ago
  Using memory without ECC on the so-called "consumer" devices, in opposition with the "professional" devices, a.k.a. servers and workstations, has been caused by Intel, from 1994, when they have introduced the second generation of Pentium CPUs, to 1995, when they have introduced Pentium Pro. (The 1st generation of Pentium, the 60/66 MHz models, had been introduced in 1993, while the 2nd generation, the 90/100 MHz models, introduced in 1994, used a different socket and different motherboards.) Unlike with the previous Intel CPUs, Intel had the idea to introduce a market segmentation between Pentium and Pentium Pro (for the successors of Pentium Pro, Intel created the Xeon brand, a couple of years later). Therefore, Intel has retained the ability to detect and or correct memory errors only in the Pentium Pro chipsets (at that time the memory controllers were in the so called northbridge, a part of the chipset, and not in the CPU), while removing this feature from the Triton chipset intended for Pentium. While Intel has initiated this market segmentation policy, between "amateurs" and "professionals" (unlike IBM, which since the first IBM PC had always included memory error detection via parity), both the memory module vendors and the makers of other CPUs have been also happy to follow this policy, because it allows them to extract much more money from the knowledgeable users than the cost of adding ECC, while also having larger profit margins when selling to naive users, because the elimination of ECC/parity has never caused any price reduction. When this feature was removed, all the new motherboards and modules without parity/ECC had the same prices as the previous models with error detection (for many years, the memory errors were detected via parity, but then the memory controllers were improved, so that when using the same number of extra bits, i.e. the same memory modules and motherboards as for parity, single errors could be corrected, not only detected).
- RL_Quine 4y ago
  I specifically bought hardware (APU2) for my wifi routers that has ECC, it's just not something that's commonly on hardware you could buy off the shelf. Like the other comment said, it's a stupid product differentiation thing that Intel did. This hardware for the point, uses a very old AMD Geode processor.
  - yeauldfellows 4y ago
    I'm also looking at building a router with ecc ram. Do you have any hardware recommendations?

colechristensen 4y ago

It’s not that errors don’t happen it’s that they are rare and the surface area of them affecting something important in an important way are incredibly rare. I don’t care about triggering an occasional bug or a bit flip in a video stream, these things are inconsequential. If a bit gets flipped in a photo it’ll be a very slightly different photo. A piece of text will be slightly different… if either had the luck to be in memory ready to write when hit, in dozens of gigabytes of memory. The most likely consequence of a bit flip is nothing at all happening because it hit unallocated memory. The next most likely consequence is nothing as it hit a piece of program memory that has no effect on operation and gets overwritten in moments. ECC zealots are really excited about preventing something that just doesn’t happen all that often: actual data corruption with permanent significant effects.

RL_Quine 4y ago
My point was that you don't know when corruption has had an effect, because you're eschewing a method of detecting it.

matheusmoreira 4y ago

> my wifi routers have ECC memory This is really weird. How come even routers have ECC memory while our actual computers don't? Why can't all memory just be ECC memory? I don't even see the point of non-ECC memory. Everything has error correction built-in: hard drives, SSDs, even optical media. Yet RAM doesn't?

adrian_b 4y ago
Using memory without ECC on the so-called "consumer" devices, in opposition with the "professional" devices, a.k.a. servers and workstations, has been caused by Intel, from 1994, when they have introduced the second generation of Pentium CPUs, to 1995, when they have introduced Pentium Pro. (The 1st generation of Pentium, the 60/66 MHz models, had been introduced in 1993, while the 2nd generation, the 90/100 MHz models, introduced in 1994, used a different socket and different motherboards.) Unlike with the previous Intel CPUs, Intel had the idea to introduce a market segmentation between Pentium and Pentium Pro (for the successors of Pentium Pro, Intel created the Xeon brand, a couple of years later). Therefore, Intel has retained the ability to detect and or correct memory errors only in the Pentium Pro chipsets (at that time the memory controllers were in the so called northbridge, a part of the chipset, and not in the CPU), while removing this feature from the Triton chipset intended for Pentium. While Intel has initiated this market segmentation policy, between "amateurs" and "professionals" (unlike IBM, which since the first IBM PC had always included memory error detection via parity), both the memory module vendors and the makers of other CPUs have been also happy to follow this policy, because it allows them to extract much more money from the knowledgeable users than the cost of adding ECC, while also having larger profit margins when selling to naive users, because the elimination of ECC/parity has never caused any price reduction. When this feature was removed, all the new motherboards and modules without parity/ECC had the same prices as the previous models with error detection (for many years, the memory errors were detected via parity, but then the memory controllers were improved, so that when using the same number of extra bits, i.e. the same memory modules and motherboards as for parity, single errors could be corrected, not only detected).
RL_Quine 4y ago
I specifically bought hardware (APU2) for my wifi routers that has ECC, it's just not something that's commonly on hardware you could buy off the shelf. Like the other comment said, it's a stupid product differentiation thing that Intel did. This hardware for the point, uses a very old AMD Geode processor.
- yeauldfellows 4y ago
  I'm also looking at building a router with ecc ram. Do you have any hardware recommendations?