system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are the programmers in big companies like Apple, Microsoft or Google able to all stay on the same page with such large projects?

For instance how are they able to maintain such large code bases and ultimately achieve their goal of finishing super large projects like OS releases and such?
gpt
Split it in many pieces that are as independent as possible (and if you do it wrong, you can screw up massively in this step before any line of code is written). There is no way to know everything in detail in a modern operating system, or any other large software project. It is not necessary - most lines of code are for some specific function, and independent of other functions. If you program some user interface in a random system tool, you do not have to know how the operating system handles its files, for example. Even if you have to access files, you do not have to know how those are handled: the code for file handling gives you functions like "list all files in this folder" which you can call - and you don't care about the code that actually produces this list.