How does reading/writing files work?

Question

Python

I was wondering how reading/writing (to) files works. Usually I opened small files weighing a few KB, but then I became interested in how application logs work. They create files that report on their work. My application also needed logs, but I thought: "How does this work? Because my file can reach a size of several hundred MB, or several GB. Wouldn't this be some kind of load?". I've seen people ask what's best to use for reading multi-GB files, but I haven't seen anyone ask anything about writing. What is the difference between these modes? How do they work? Will there be additional load due to file weight?

Answer 1

It is possible and necessary to read the file partially. And in order to write to a file, it is not necessary to read it all or even read it.
PS This is why I insist on not getting into programming without at least basic computer knowledge

Answer 2

Add, as a rule, to the end. Logs can really grow into hundreds of GB without a drop in performance.