Catching disk latency in the act
By bmc on Dec 31, 2008
This may seem silly, but it's not farfetched: Brendan actually made this discovery while exploring drive latency that he had seen in a lab machine due to a missing screw on a drive bracket. (!) Brendan has more details on the discovery, demonstrating how he used the Fishworks analytics to understand and visualize it.
If this has piqued your curiosity about the nature of disk mechanics, I encourage you to read Jon Elerath's excellent ACM Queue article, Hard disk drives: the good, the bad and the ugly! As Jon notes, noise is a known cause of what is called a non-repeatable runout (NRRO) -- though it's unclear if Brendan's shouting is exactly the kind of noise-induced NRRO that Jon had in mind...