Making some pseudorandom data fast

## Introduction For a particular experiment at work a few years ago, I found myself needing to make about 10TiB of hard to compress data. /dev/urandom is &ldquo;slow&rdquo; at 400ish MB/s on machines I have access to. I put that in quotes because that still seems fast to me, but 10TiB would take about 7 hours at that speed. Unfortunately I don&rsquo;t remember where I came across this trick, but…