I was located in the Bay Area so my screening interview was also onsite. It was a one hour interview with the a senior executive at PernixData. The question first involved coding up a problem and then went on to more of a design problem. I think I did fairly well at this as I did receive an invite for onsite. There were two sets of onsite interviews - 3 hours each. Each interview focused on different aspects. Kernel space knowledge, synchronization, storage system design, complexity of algorithms, programming questions. Each involved writing code on the whiteboard.

CTO reached out to me via LinkedIn. Standard Silicon Valley style interview process. Talked to 5 engineers and the CTO. Every engineer had either a coding or design test in different areas. Be sure to understand important data structures like tries, b-trees and hash tables. Operating system, kernel and distributed systems background has to be solid as a lot of questions evolve around concurrency, memory management and cache coherency. Coding is done in plain C or pseudo code for kernel positions. Some algorithms asked are recursive but nothing to be scared of.