> I'm not concerned If someone happens to know some esoteric trick that they could Google search (Unless of course you're applying for a position at a company that manufactures very low level devices like microcontrollers or embedded systems and questions like this are _actually relevant_).

Erasure correction is a very useful trick for data-engineers. I don't think this is a microcontroller trick, as much as a data-resliliency trick.

The XOR-trick is how you implement RAID5 most efficiently. A proper discussion / interview would probably describe the XOR trick, and then see if the engineer is smart enough to understand the difference between erasure and errors.

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With a blog post describing the XOR trick ahead of us: now I ask you (the audience): what is the difference between an erasure and an error? Why can this XOR-trick protect against an erasure, but NOT an error? And how does this relate to RAID5's known failure cases?

But at that point, I'm interviewing for someone who has passed a data communications class.