Safety cut rope axe man In the first nuclear reactor, constructed by Enrico Fermi in 1942 under the bleachers of the University of Chicago football stadium, the control rods were held up by a manila rope. A man with an axe was told to cut the rope if the reactor got out of hand. This "safety cut rope axe man" is supposedly the origin of the term SCRAM for an emergency shutdown procedure. Brian Hayes, Infrastructure: A Guide to the Industrial Landscape wordsacronymsenergy
Two kinds of usability An Article by Ryan Singer world.hey.com I divide usability problems into two kinds: Perceptual: "They couldn't figure out what to do next", "they couldn't find the feature", "they didn't know they could click that button..." etc. Domain-specific: "We need a way to jump back here because in their workflow this happens..." In general, usability testing only catches type 1 perceptual problems. Because in those tests you take people out of the real world and assign them tasks. Usability testing doesn't catch domain-specific problems because they only come up in real life use. uxethnography