It’s good to look at physical systems like this to understand how we’ve landed up with software systems which we take for granted. For example, when I was abou

It’s good to look at physical systems like this to understand how we’ve landed up with software systems which we take for granted. For example, when I was about 10 in the early 90s, I remember being taught how to use our school library which at that time had no computers. The books were sorted on the shelves by author’s surname, so finding them when you knew the author was easy, but what about when you only knew the book title? Well the solution to that was to look through little cards in a series of draws sorted by book title, when you found the card it had the author name and you could then easily find the book. These cards were called index cards. Software databases model this system. A clustered index is essentially equivalent to the books being on the shelves in a particular order, while a normal index is like the index cards. Email was essentially modelled off of real world postal systems. And when I read this article talking about standard box sizes, I think of cluster sizes on computer disk drives. Software is a lot less abstract than a lot of people may realise.