[saberience]

You could answer that example problem just by being someone who reads Hackernews a bunch, since the "replace spark cluster with random unix tools" article appears here regularly. IMO, that doesn't really define being a principal engineer, it's basic.

[foobarian]

Principal engineer: arrives at company, notices expensive Spark cluster, replaces with one server running shell scripts

Double digit-strong data science team: speechless

[nilkn]

I don't even agree that this is a defining quality of a principal engineer. This is part of our standards for a senior developer, and it's something we coach people on from the get-go.