Some years back, I got myself a copy of Andrew Hodges "Alan Turing - The Enigma", a biography and IMO generally a good read, but also with some gems regarding v

Some years back, I got myself a copy of Andrew Hodges "Alan Turing - The Enigma", a biography and IMO generally a good read, but also with some gems regarding very early computing history in it. Specifically, after WWII, Turing worked on the ACE 1 (later reduced to Pilot ACE) project to build an electronic computer, which didn't really progress due to management and bureaucracy overhead. He eventually went to Manchester, once they got their Manchester Mark 1 off the ground, which they tried to commercialize as "Ferranti Mark 1" (https://en.wikipedia.org/wiki/Ferranti_Mark_1 https://en.wikipedia.org/wiki/Ferranti_Mark_1). While employed for the University, Turing IIRC continued to work as an external consultant for whatever became of G.C. & C.S. on the side. According to the book, he convinced them to buy such a machine (presumably for crypt-analysis?) and, on the Manchester side of things, insisted on some modifications to be made, including a "horizontal adder", so it could count the number of bits set in a word with a single instruction, i.e. a popcount instruction. This would pre-date the IBM Stretch mentioned in the article.