The old typesetters had the letters arranged as 'etaoin shrdlu' because these letters were the most commonly used letters in the language.
Not quite. The Linotype keyboards are set up different from typewriters. The typesetters would occasionaly make a mistake and would run finger across the keys and up would pop 'etaoin shrdlu' in the cast column of type - the typesetters eye was trained to spot the phrase and they could locate the error easily and remove it. The Linotype - invented by Mergenthaler - is from the days of "hot type" and isn't seen too much anymore.The print was clearer and pages looked better (said the old hot type & press reporter with a sigh.) I know The Lowell SUN and (I think) The New York Times still have hot type presses.
http://mmd.foxtail.com/Archives/Digests/199712/1997.12.07.16.html Don't yell at me I tried Makeashorterlink but it didn't give me one although it said it had been created. I dunno'
Anyways - this link is a forum and has displayes an entry re Linotype machines. They guy writing the entry has one in his garage! Or you can Dogpile "Merganthaler+Linotype" and get entries - one of which has a photo of a Linotype
Have fun.