Leader of Birmingham.pm [pm.org] and a CPAN author [cpan.org]. Co-organised YAPC::Europe in 2006 and the 2009 QA Hackathon, responsible for the YAPC Conference Surveys [yapc-surveys.org] and the QA Hackathon [qa-hackathon.org] websites. Also the current caretaker for the CPAN Testers websites and data stores.
If you really want to find out more, buy me a Guinness
Why are servers (and other rack mounted equipmnent) measured in U and why is 1U 1.75 inches? Obviously there has to be some sort of standardised measure, but why 1.75 inches? Why not 2 inches or 5cm or 1 hand? And why are racks 19 inches wide? Why not 20inches?
I remember hearing a similar question of why railway tracks (the gauge) are the size they are. I've heard the answer on several occasions, but can't remember at the moment. But I've never thought about rack sizes before. Anyone know why, or have any links to explain them?