[dmatlack]

As OP said, you would not be able to google the specific B-Tree question because if you don't know about B-Trees you wouldn't know that you need to google it.

There's a difference between things you know you don't know (and therefore can google), and things you don't know you don't know (and therefore will not google).

[marknutter]

"I can see you're a bright individual and you have a great track record for writing and shipping good software, which is clear from your github account and your previous employers' endorsements. I have no doubt you'll be able to come up to speed on <insert obscure discipline> which is something we use a lot around here. We're looking for people who can learn quickly. Welcome aboard!"