5 ms·

I interpreted the comment a bit more generously that you did. You're absolutely corrent that it's possible, and I'll go as far as to say even desireable, to wr

I interpreted the comment a bit more generously that you did. You're absolutely corrent that it's possible, and I'll go as far as to say even desireable, to write provable correct code. However, I've never seen a demonstration of probably correct hardware. I interpreted the comment as reminder that even binary is, ultimately, a leaky abstraction. I used to work in a facility where they'd test systems for radiation hardness. Get the system running, then shoot a proton beam travelling a significant fraction of the speed of light directly at the processor. It doesn't matter if the code was proven correct Dijkstra, it will eventually manifest bugs under these conditions.

lmm 11y ago
I don't think anyone proves their hardware from basic physics[1], but hardware comes with specs and tolerances. If your software needs to operate in a high-radiation environment, you buy appropriate hardware and potentially take other countermeasures (e.g. multiple processors executing in sync). [1] practically we resort to empirical testing to confirm that hardware conforms to its spec. But as your sibling says, that's no excuse not to do better in the places where we can.
- nickpsecurity 11y ago
  EAL7 data diodes with octocouplers and EMSEC do. Oh, snap, you didnt see that coming! :P
sfk 11y ago
Perhaps don't put your system in the path of a proton beam? I've had a large test suite that consistently used 8GB running for three years without ECC RAM. Any bit flip would have been caught by the test suite. My conclusion is that bit flips are entirely exaggerated (probably by the hardware industry for obvious reasons).
- effie 11y ago
  Do you have the suite published? The frequency of errors depends on how much memory and in which conditions it is being used. Datacenters, supercomputers, even personal workstations used for scientific calculations benefit from error correction. Check this out: http://techcrunch.com/2009/11/02/new-study-proves-that-ecc-memory-may-well-be-worth-the-extra-cost/ http://techcrunch.com/2009/11/02/new-study-proves-that-ecc-m...
  - deleted 11y ago
    [deleted]
- sfk 11y ago
  Downvoted again by mindless mainstream. Have another go, perhaps you'll reach -10.
  - sfk 11y ago
    Usually comments that complain about downvotes are downvoted. Have another go, perhaps you'll reach -20. If you persist, you will be eminently qualified as a Wikipedia admin.
  - sfk 11y ago
    Wow, after 7 days someone has bothered to downvote this. Here, you have another chance.

lmm 11y ago

I don't think anyone proves their hardware from basic physics[1], but hardware comes with specs and tolerances. If your software needs to operate in a high-radiation environment, you buy appropriate hardware and potentially take other countermeasures (e.g. multiple processors executing in sync). [1] practically we resort to empirical testing to confirm that hardware conforms to its spec. But as your sibling says, that's no excuse not to do better in the places where we can.

nickpsecurity 11y ago
EAL7 data diodes with octocouplers and EMSEC do. Oh, snap, you didnt see that coming! :P

sfk 11y ago

Perhaps don't put your system in the path of a proton beam? I've had a large test suite that consistently used 8GB running for three years without ECC RAM. Any bit flip would have been caught by the test suite. My conclusion is that bit flips are entirely exaggerated (probably by the hardware industry for obvious reasons).

effie 11y ago
Do you have the suite published? The frequency of errors depends on how much memory and in which conditions it is being used. Datacenters, supercomputers, even personal workstations used for scientific calculations benefit from error correction. Check this out: http://techcrunch.com/2009/11/02/new-study-proves-that-ecc-memory-may-well-be-worth-the-extra-cost/ http://techcrunch.com/2009/11/02/new-study-proves-that-ecc-m...
- deleted 11y ago
  [deleted]
sfk 11y ago
Downvoted again by mindless mainstream. Have another go, perhaps you'll reach -10.
- sfk 11y ago
  Usually comments that complain about downvotes are downvoted. Have another go, perhaps you'll reach -20. If you persist, you will be eminently qualified as a Wikipedia admin.
- sfk 11y ago
  Wow, after 7 days someone has bothered to downvote this. Here, you have another chance.