That is more than I am asking for, thank you very much for replying in details!!

Yes. It was a bit wordy. What I am trying to get accross is that there are two aspects to system structure. The physical aspect in terms of how you organize your progams/components/source files whatever in the file system and, therefore, within the project itself (as you can see in the second screen dump I posted). This is reflecting their particular role in the system. Which logical layer they serve and operate in. This feeds into the maintainability of teh system. There is no technical reason as to why all of the system files in that system couldn't have all been in one folder. Just one folder. The system would still work. But it would be far more difficult to find what you are looking for when it comes to maintaining the system. So that's the physical organization which, as I say, has no impact on performance. Then there is the logical layering that I have covered earlier. I have attached a screen dump of how that system is organized in the file system. It's the same as you saw in the earlier project screen of course.

 

something (from the pre-history . . . about ~ https://www.dosbox.com/ )

(~ABOUT►)

https://flic.kr/p/2ioBzEu
(+MORE INTENSE)

 

something (from the pre-history . . . about ~ https://www.dosbox.com/ )
View attachment 198198
(+MORE INTENSE)
View attachment 198199

Nice meaningful file names I see. This is from a time when all you had was 8 bytes. Thank God those days are far behind us. I had a dabble with Pascal decades ago but couldn't really find much use for it.