[ChuckMcM]

Kind of like buying a gun for self protection and then having an intruder get hold of it and kill you with it. In a talk I gave to some Swiss banks about security a looooong time ago I talked briefly about security measures as vulnerabilities which are analogous to data protection bits being the source of data corruption errors. You have to evaluate whether the system as a whole with is more or less (or the same!) level of secure with the code you've added for security.

[sitkack]

I hadn't really thought about ECC bits getting errors and thus corrupting the thing they were supposed to protect.

Do you know if hardware uses http://en.wikipedia.org/wiki/Reed-Muller_Code for the ECC bits?

[userbinator]

At least which schemes like Reed-Solomon, the "ECC bits" conceptually are not a separate piece of data that is computed and then added to the data to be protected, despite that being how it is usually implemented. The algorithm really "expands" the data, so the redundancy is spread out across all the bits. Thus any bit errors anywhere in the whole encoded "codeword" can be corrected, up to the limits of the code.

[ChuckMcM]

I believe they use Reed-Solomon encoding but as it is up to the memory controller to implement it can change. The memory just provides the extra bits for the software to use. In our fictional gun ownership example it would be like the owner hiding multiple guns around the house so that if one was compromised by an intruder they could still defend themselves. :-)