Quite a premise: "Giant monolithic source-code repositories are one of the fundamental pillars of the back end infrastructure in large and fast-paced software companies."
facebook, google, airbnb, quora, many more all use monorepo
obviously there are many others who do not use monorepo (amazon comes to mind) but it's reasonable to claim that they are actually widely used and fundamental when used
Does anybody know how these companies development environments look like? I know about Piper at Google but how do the rest manage? Does every single engineer have the entire monorepo in their machines?
At facebook, a virtual filesystem (https://github.com/facebookexperimental/eden) + change monitor (https://facebook.github.io/watchman/) = source control operations run in O(files I have modified) instead of O(size of repository) time